SlideShare a Scribd company logo
MBSM 713: BIOCHEMISTRY OF ANTI
MICROBIAL AGENTS
Lecture Three:
1.1.AntiviralsAntivirals
2.2.AntifungalsAntifungals
3.3.Antihelmitic drugsAntihelmitic drugs
Dr. G. Kattam Maiyoh
01/23/15
GKM/KISIIU/MBSM713
/BIOC.AMIC.AGENS.LEC03
1
01/23/15
GKM/KISIIU/MBSM713
/BIOC.AMIC.AGENS.LEC03
2
Understanding VirusesUnderstanding Viruses
They are different from other MicrobesThey are different from other Microbes
Viral replicationViral replication
• A virus cannot replicate on
its own
• It must attach to and enter
a host cell
• It then uses the host cell’s
energy to synthesize DNA,
RNA and protein.
01/23/15
GKM/KISIIU/MBSM713
/BIOC.AMIC.AGENS.LEC03
3
Understanding VirusesUnderstanding Viruses
Viruses are
difficult to kill
because they live
inside the cells
• Any drug that kills
a virus MAY also kill
cells
01/23/15
GKM/KISIIU/MBSM713
/BIOC.AMIC.AGENS.LEC03
4
Anti-viral drugsAnti-viral drugs
• Certain viruses
multiply in the
cytoplasm but
others do in the
nucleus
• Most multiplication
take place before
diagnosis is made
01/23/15
GKM/KISIIU/MBSM713
/BIOC.AMIC.AGENS.LEC03
6
Anti-Viral drugs
• Many antiviral drugs are Purine or
Pyrimidine analogs.
• Many antiviral drugs are Prodrugs. They
must be phosphorylated by viral or cellular
enzymes in order to become active.
• Most anti-viral agents inhibits active
replication so the viral growth resumes
after drug removal.
01/23/15
GKM/KISIIU/MBSM713
/BIOC.AMIC.AGENS.LEC03
7
Antivirals how they act
Key characteristics of antiviral drugs
Able to enter the cells infected with virus
Interfere with viral nucleic acid synthesis and/or
regulation
Some drugs interfere with ability of virus to bind to
cells
Some drugs stimulate the body’s immune system
Best responses to antiviral drugs are in patients with
competent immune systems
A healthy immune system works synergistically with
the drug to eliminate or suppress viral activity
01/23/15
GKM/KISIIU/MBSM713
/BIOC.AMIC.AGENS.LEC03
8
Antiviral Medications
Antiviral drugs
 Used to treat infections caused by
viruses other than HIV
Antiretroviral drugs
 Used to treat infections caused by HIV,
the virus that causes AIDS
01/23/15
GKM/KISIIU/MBSM713
/BIOC.AMIC.AGENS.LEC03
9
Antiviral Drugs: Nonretroviral
Mechanism of action
 Inhibit viral replication (Does not necessarily mean
viral DNA replication.)
Used to treat non-HIV viral infections
 Influenza viruses
 HSV (herpes simplex virus), VZV (vericella zoster virus)
 CMV (cytomegalovirus)
 Hepatitis A, B, C (HAV, HBV, NCV)
Adverse Effects
 Vary with each drug
 Healthy cells are often killed also, resulting in serious toxicities
01/23/15
GKM/KISIIU/MBSM713
/BIOC.AMIC.AGENS.LEC03
10
Anti-viral drugs
• Current anti-viral agents do not eliminate non-
replicating or latent virus
• Effective host immune response remains
essential for the recovery from the viral
infection
• Clinical efficacy depends on achieving
inhibitory conc. at the site of infection within
the infected cells
01/23/15
GKM/KISIIU/MBSM713
/BIOC.AMIC.AGENS.LEC03
11
Anti-viral drugsAnti-viral drugs
Stages of viral replication
• Cell entry – attachment
- penetration
• Uncoating
• Transcription of viral genome
• Translation
• Assembly of virion components
• Release
01/23/15
GKM/KISIIU/MBSM713
/BIOC.AMIC.AGENS.LEC03
12
01/23/15
GKM/KISIIU/MBSM713
/BIOC.AMIC.AGENS.LEC03
13
Anti-viral drugs
Anti-herpes virus agents
• Acyclovir / Valacyclovir
• Famciclovir / Penciclovir
• Ganciclovir / Cidofovir
• Foscarnet
• Trifluridine / Idoxuridine / Vidarabine
01/23/15
GKM/KISIIU/MBSM713
/BIOC.AMIC.AGENS.LEC03
14
• Valacyclovir is a prodrug of Acyclovir
with better bioavailability.
• Famciclovir is hydrolyzed to
Penciclovir and has greatest
bioavailability.
• Penciclovir is used only topically
whereas Famciclovir can be
administered orally.
01/23/15
GKM/KISIIU/MBSM713
/BIOC.AMIC.AGENS.LEC03
15
Features
PHARMACOLOGY OF
ACYCLOVIR AND
CONGENERS
• Acyclovir,
Valacyclovir,
Ganciclovir,
Famciclovir,
Penciclovir
• All are guanine
nucleoside analogs.
01/23/15
GKM/KISIIU/MBSM713
/BIOC.AMIC.AGENS.LEC03
16
Mechanism of action of Acyclovir and
congeners :
• All drugs are phosphorylated by a viral
thymidine-kinase, then metabolized by host
cell kinases to nucleotide analogs.
• The analog inhibits viral DNA-
polymerase
• Only actively replicating viruses are
inhibited
01/23/15
GKM/KISIIU/MBSM713
/BIOC.AMIC.AGENS.LEC03
17
• Acyclovir is thus
selectively activated
in cells infected with
herpes virus.
• Uninfected cells do
not phosphorylate
acyclovir.
01/23/15
GKM/KISIIU/MBSM713
/BIOC.AMIC.AGENS.LEC03
18
Mechanism of Action of Acyclovir
01/23/15
GKM/KISIIU/MBSM713
/BIOC.AMIC.AGENS.LEC03
19
Antiviral spectrum :
• Acyclovir: HSV-1, HSV-2, VZV, Shingles.
• Ganciclovir / Cidofovir : CMV
• Famciclovir : Herpes genitalis and shingles
• Foscarnet : HSV, VZV, CMV, HIV
• Penciclovir : Herpes labialis
01/23/15
GKM/KISIIU/MBSM713
/BIOC.AMIC.AGENS.LEC03
20
Pharmacokinetics of Acyclovir :
–Oral bioavailability ~ 20-30%
–Distribution in all body tissues including
CNS
–Renal excretion: > 80%
–Half lives: 2-5 hours
–Administration: Topical, Oral , IV
01/23/15
GKM/KISIIU/MBSM713
/BIOC.AMIC.AGENS.LEC03
21
Adverse effects of Acyclovir /
Ganciclovir
• Nausea, vomiting and diarrhea
• Nephrotoxicity - crystalluria,
haematuria, renal insufficiency
• Myelosuppression – Neutropenia and
thrombocytopenia – Ganciclovir
01/23/15
GKM/KISIIU/MBSM713
/BIOC.AMIC.AGENS.LEC03
22
Therapeutic uses :
Acyclovir is the drug of choice for:
• HSV Genital infections
• HSV encephalitis
• HSV infections in immunocompromised patient
Ganciclovir is the drug of choice for:
• CMV retinitis in immunocompromised patient
• Prevention of CMV disease in transplant patients
CMV = Cytomegalovirus is a serious eye infection
of the retina
01/23/15
GKM/KISIIU/MBSM713
/BIOC.AMIC.AGENS.LEC03
23
Cidofovir :
• It is approved for the treatment of CMV
retinitis in immunocompromised patients
• It is a nucleotide analog of cytosine – no
phosphorylation required.
• It inhibits viral DNA synthesis
• Available for IV, Intravitreal inj, topical
• Nephrotoxicity is a major disadvantage.
01/23/15
GKM/KISIIU/MBSM713
/BIOC.AMIC.AGENS.LEC03
24
PHARMACOLOGY OF FOSCARNET
• Foscarnet is an inorganic
pyrophosphate analog  
• It directly inhibits viral DNA and RNA
-polymerase and viral reverse
transcriptase (it does not require
phosphorylation for antiviral activity)
01/23/15
GKM/KISIIU/MBSM713
/BIOC.AMIC.AGENS.LEC03
28
Foscarnet
• HSV-1, HSV-2, VZV, CMV and
HIV.
• Oral bioavailability ~ 10-20%
• Distribution to all tissues
including CNS
• Administration: IV
01/23/15
GKM/KISIIU/MBSM713
/BIOC.AMIC.AGENS.LEC03
29
Adverse effects of Foscarnet
• Hypocalcemia and hypomagnesemia (due
to chelation of the drug with divalent
cations) are common.
• Neurotoxicity (headache, hallucinations,
seizures)
• Nephrotoxicity (acute tubular nephrosis,
interstitial nephritis)
01/23/15
GKM/KISIIU/MBSM713
/BIOC.AMIC.AGENS.LEC03
30
Therapeutic uses of Foscarnet
• It is an alternative drug for
• HSV infections (acyclovir resistant /
immunocompromised patient )
• CMV retinitis (ganciclovir resistant /
immunocompromised patient )
01/23/15
GKM/KISIIU/MBSM713
/BIOC.AMIC.AGENS.LEC03
31
Respiratory viral infections
Influenza –
• Amantadine / Rimantadine
• Oseltamivir / Zanamavir
RSV bronchiolitis –
• Ribavirin
01/23/15
GKM/KISIIU/MBSM713
/BIOC.AMIC.AGENS.LEC03
32
Amantadine and Rimantadine :
Influenza
• Prevention & Treatment of influenza A
• Inhibition of viral uncoating by
inhibiting the viral membrane protein
M2
• Amantadine has anti-parkinsonian
effects.
01/23/15
GKM/KISIIU/MBSM713
/BIOC.AMIC.AGENS.LEC03
33
Pharmacokinetics of Amantadine
• Oral bioavailability ~ 50-90%
• Amantadine cross extensively
BBB whereas Rimantadine
does not cross extensively .
• Administration: Oral
01/23/15
GKM/KISIIU/MBSM713
/BIOC.AMIC.AGENS.LEC03
34
Neuraminidase inhibitors : Influenza
Oseltamivir / Zanamavir
• Influenza contains an enzyme neuraminidase
which is essential for the replication of the virus.
• Neuraminidase inhibitors prevent the release
of new virions and their spread from cell to cell.
01/23/15
GKM/KISIIU/MBSM713
/BIOC.AMIC.AGENS.LEC03
35
Neuraminidase inhibitors : Influenza
Oseltamivir / Zanamavir
• These are effective against both types of
influenza A and B.
• Do not interfere with immune response to
influenza A vaccine.
• Can be used for both prophylaxis and acute
treatment.
Administration
• Oseltamivir is orally administered.
• Zanamavir is given intranasal.
01/23/15
GKM/KISIIU/MBSM713
/BIOC.AMIC.AGENS.LEC03
36
Viru
s
 
    Diseases
Drug(s) of
choice
Alternative
drugs
FLU
A
 
Influenza Amantadine
Rimantadine
RSV
Pneumonia,
bronchiolitis
Ribavirin
(aerosol)
 
HSV
 
Genital herpes Acyclovir Foscarnet
 
  Keratitis
Conjunctivitis
Trifluridine
Idoxuridine
Vidarabine
 
Encephalitis Acyclovir
 
  Neonatal HSV
infection
Acyclovir Vidarabine
  Herpes infections in
immuno-
compromised host
Acyclovir Foscarnet
01/23/15
GKM/KISIIU/MBSM713
/BIOC.AMIC.AGENS.LEC03
48
VZV
 
 
In normal host No therapy
 
In immunocompro-
mised host, or during
pregnancy
Acyclovir Foscarnet
CMV Retinitis Ganciclovir Foscarnet
HIV
AIDS
HIV antibody
positive with CD4
count < 500/mm3
Zidovudine ±
protease
inhibitors
Didanosine,
Stavudine
HBV
HCV
Hepatitis B, C Interferons
 
01/23/15
GKM/KISIIU/MBSM713
/BIOC.AMIC.AGENS.LEC03
49
Antiretroviral Drugs
HAART - Highly active
antiretroviral therapy
• Includes at least
three medications
–“cocktails”
• These medications
work in different
ways to reduce the
viral load
01/23/15
GKM/KISIIU/MBSM713
/BIOC.AMIC.AGENS.LEC03
50
Antiretroviral Drugs
• Reverse transcriptase inhibitors (RTIs)
– Block activity of the enzyme reverse transcriptase, preventing
production of new viral DNA
• Include:
– Nucleoside RTIs (NRTIs)
– Nonnucleoside RTIs (NNRTIs)
– Nucleotide RTIs (NTRTIs)
• Examples
abacavir (Ziagen) delavirdine (Rescriptor)
didanosine (Videx) lamivudine (Epivir)
stavudine (Zerit) tenofovir (Viread)
01/23/15
GKM/KISIIU/MBSM713
/BIOC.AMIC.AGENS.LEC03
51
Antiretroviral Drugs
• Protease inhibitors (PIs)
– Inhibit the protease a
retroviral enzyme,
preventing viral replication
– Examples:
amprenavir (Agenerase)
indinavir (Crixivan)
nelfinavir (Viracept)
ritonavir (Norvir)
saquinavir (Invirase)
01/23/15
GKM/KISIIU/MBSM713
/BIOC.AMIC.AGENS.LEC03
52
Antiretroviral DrugsAntiretroviral Drugs
• Fusion inhibitors
– Inhibit viral fusion,
preventing viral
replication
– Newest class of
antiretroviral drugs
– Example: enfuvirtide
(Fuzeon)
01/23/15
GKM/KISIIU/MBSM713
/BIOC.AMIC.AGENS.LEC03
53
Antiretroviral Drugs
• Combinations of multiple antiretroviral
medications are common
• Adverse effects vary with each drug
and may be severe−monitor for dose-
limiting toxicities
• Monitor for signs of opportunistic
diseases
01/23/15
GKM/KISIIU/MBSM713
/BIOC.AMIC.AGENS.LEC03
54
Antiretroviral Drugs:Antiretroviral Drugs:
Adverse EffectsAdverse Effects
 Numerous and varyNumerous and vary
with each drugwith each drug
Drug therapy may need
to be modified because
of adverse effects
Goal is to find the
regimen that will best
control the infection
with a tolerable
adverse effect profile
 Medication regimens change
during the course of the illnessduring the course of the illness
01/23/15
GKM/KISIIU/MBSM713
/BIOC.AMIC.AGENS.LEC03
55
Antiviral DrugsAntiviral Drugs
ANTIFUNGAL DRUGS
Systemic & Topical
Some are fungistatic,
while others are fungicidal
01/23/15 56
GKM/KISIIU/MBSM713
/BIOC.AMIC.AGENS.LEC03
Fungal Infection in Humans =
Mycosis
Fungal Infection in Humans =
Mycosis
• Major Types of Mycoses
– superficial
– cutaneous
– subcutaneous
– systemic
– opportunistic
• Symptoms vary from cosmetic to life
threatening
01/23/15 57
GKM/KISIIU/MBSM713
/BIOC.AMIC.AGENS.LEC03
Antifungal Agents
• Polyene antibiotic
• The polyene antibiotics bind with sterols in the fungal cell
membrane, principally ergosterol. This causes the cell's
contents to leak out and the cell dies. Animal cells contain
cholesterol instead of ergosterol and so they are much less
susceptible.
– Nystatin
– Amphotericin B (may be administered liposomally)
– Natamycin
– Rimocidin
– Filipin
– Pimaricin
01/23/15 58
GKM/KISIIU/MBSM713
/BIOC.AMIC.AGENS.LEC03
Antifungal Agents
Imidazole and triazole
• The imidazole and triazole groups of antifungal drugs
inhibit the enzyme cytochrome P450 14α-
demethylase. This enzyme converts lanosterol to
ergosterol, and is required in fungal cell membrane
synthesis. These drugs also block steroid synthesis in
humans.
• Imidazoles:
• Miconazole Bifonazole
• Ketoconazole Butoconazole
• Clotrimazole Econazole
• Mebendazole Fenticonazole
• Isoconazole Oxiconazole
• Sertaconazole Sulconazole
• Thiabendazole Tiaconazole01/23/15 60
GKM/KISIIU/MBSM713
/BIOC.AMIC.AGENS.LEC03
Antifungal Agents
• The triazoles are newer, and are less
toxic and more effective:
• Fluconazole
• Itraconazole
• Ravuconazole
• Posaconazole
• Voriconazole
01/23/15 61
GKM/KISIIU/MBSM713
/BIOC.AMIC.AGENS.LEC03
Antifungal Agents
Allylamines
• Allylamines inhibit the enzyme squalene
epoxidase, another enzyme required for
ergosterol synthesis:
– Terbinafine - marketed as Lamisil
– Amorolfine
– Naftifine
– Butenafine
01/23/15 62
GKM/KISIIU/MBSM713
/BIOC.AMIC.AGENS.LEC03
Antifungal Agents
Echinocandin
• Echinocandins inhibit the synthesis of
glucan in the cell wall, probably via the
enzyme 1,3-β glucan synthase:
– Anidulafungin
– Caspofungin
– Micafungin
01/23/15 63
GKM/KISIIU/MBSM713
/BIOC.AMIC.AGENS.LEC03
Antifungal Agents
• Others:
–Flucytosine is an antimetabolite.
–Griseofulvin binds to polymerized microtubules
and inhibits fungal mitosis; It is derived from
the mold Penicillium griseofulvum.
–Fluocinonide
–Salicylic Acid (topical)
–Tinactin or Tolnaftate
–Potassium Iodide
01/23/15 64
GKM/KISIIU/MBSM713
/BIOC.AMIC.AGENS.LEC03
ANTHELMINTIC DRUGS
01/23/15
GKM/KISIIU/MBSM713
/BIOC.AMIC.AGENS.LEC03
65
Helminth Infections
1-Tapeworms ( cestodes)
Beef tapeworm / fish tapeworm
2- Intestinal round worms ( nematodes)
Ascaris, pinworm ,whipworm,
strongyloides, ancylostoma (
hookworm ).
A skin infection is termed cutaneous larva
migrans
Mechanism of action
• May act by causing :
• 1- paralysis of the worm.
• 2- damaging the worm leading to partial digestion or
rejection by immune mechanisms.
• 3- interfere with the metabolism of the worm.
*Worms or larvae live in tissues of host
body like muscles , viscera , menninges ,
subcutaneous tissues.
• Adult filariae live in the lymphatics,
connective tissue or mesentery of host and
produce live embryos or microfilariae, which
goes to blood stream.
• They are ingested by mosquitoes or similar
insects, they develop to larvae this secondary
host and pass to mouth parts of insect and
re-injected to humans
Ascaris lumbricoids ( common round worm)
ANTHELMINTIC DRUGS
ALBENDAZOLE
• Broad spectrum oral anthelmintic
• Drug of choice for treatment of hydatid
disease (tapeworm) and cysticercosis (pork
tapeworm)
• It is also used for the treatment of ascariasis
,tricurasis and strongyloidiasis, pinworm,
hookworm
Mechanism Of Action
1. Inhibits microtubule synthesis by binding to β –
tubulin.
2. Inhibits mitochondrial reductase causing reduced
glucose transport. Intestinal parasites are immobilized
and die slowly.
• Larvicidal in hydatid ,cysticercosis , ascariasis and
hook worm infections.
• Ovicidal in ascariasis, hookworm ,trichuriasis
Pharmacokinetics
• Formulated as Benzimidazole
carbamate
• Administered orally , absorption
increased with a fatty meal
• Metabolized in the liver to the active
metabolite called albendazole sulfoxide
Pharmacokinetics
• Plasma half life is 8-12 hours
• sulfoxide is mostly protein bound
distributes well to tissues and enters
bile,CSF & hydatid cysts.
• Metabolites are excreted in urine
Clinical uses
• Used on empty stomach when used against
intraluminal parasites but with a fatty meal when
used against tissue parasites.
1. In ascariasis ,trichuriasis ,hookworm, pin worm
infections :
2. Hydatid diseases
Albendazole (con’)
3. Neurocysticercosis:
Used with corticosteroid to decrease the
inflammation caused by dying organism and
it also reduces the duration of course for 21
days
4. Other infections: Drug of choice in
cutaneous and visceral larva migrans ,
intestinal capillariasis, giardiasis & taeniasis.
Adverse Effects
• In short term(1-3 days): Mild epigastric pain,diarrhea,
nausea, headache & insomnia.
• In long term use : for hydatid cyst and cysticercosis :
abdominal pain, headache ,fever ,fatigue, alopecia ,
increased liver enzymes , pancytopenia. Blood counts and
liver enzymes should be followed.
• Not given during pregnancy, hypersensitive people to
benzimidazole drugs & children under 2 years .
PYRANTEL PAMOATE
• Broad spectrum
• Pharmacokinetics:
– Poorly absorbed from GIT
– Half of the drug is excreted unchanged in the feces.
• Mechanism of action:
– result in paralysis of worms. It is a neuromuscular
blocking agent
Efficacy
– Very effective against luminal organisms( mature or
immature forms).
– Not effective against migratory stages in the tissues or
against ova
Clinical uses
• Pin worm given orally with or without food.
• Ascariasis
• Hookworm
Pinworm male ,female
Adverse Effects
Infrequent mild transient GI disturbance
– Drowsiness , headache ,insomnia.
– Rash ,fever
Contraindications & Cautions
– Should be used with caution in liver
dysfunction.
– Pregnancy
– Children under 2 years of age
PIPERAZINE
• Only recommended for the treatment of ascariasis
• Cure rate 90% for 2 days treatment.
• Readily absorbed orally and excreted mostly unchanged
in urine
• Mechanism of action:
Causes paralysis of ascaris by blocking acetylcholine at
myoneural junction , the live worms expelled by normal
peristalsis.
• Treatment
• Treatment is continued for 3-4 days or repeated after
one week in case of heavy infections.
Adverse Effects
• GI disturbance
• Neurotoxicity ,allergic reactions .
• Contraindications
• Epilepsy or a history of epilepsy
• Impaired liver or kidney functions
• pregnancy
• Chronic neurologic disease
NICLOSAMIDE
• Second-line drug for treatment of most
tapeworm infections.
• Mechanism of action:
• Adult worm( not ova) is rapidly killed by
inhibition of oxidative phosphorylation .
• Pharmacokinetics:
• Poorly absorbed from gut & excreted in urine.
Clinical Uses
• Treatment of most forms of tapeworms.
• Not effective against cysticercosis or hydatic
disease.
• Given in the morning on empty stomach.
• Purgative is necessary to purge all dead
segments& prevent liberation of ova.
Adverse effects &
Contraindications
• Mild ,infrequent and transitory GI disturbance
• Alcohol consumption should be avoided
• Not indicated in children under 2 years of age
or in pregnancy.
DIETHYL CARBAMAZINE
• Drug of choice for the treatment of filariasis and
tropical eosinophilia.
• Pharmacokinetics:
• Rapidly absorbed from gut
• Half- life is 2-3 hours
• The drug should be given after meals
• It is excreted in urine as unchanged or metabolite.
• Dosage is reduced in urinary alkalosis and renal
impairment.
Mechanism Of Action
• Immobilizes microfilariae and alters their
surface structure ,displacing them from tissues
& making them susceptible to destruction by
host defense mechanism
• It has immunosuppressive effects
Adverse Effects
• Fever , malaise, papular rash, headache, GI
disturbance,cough. Chest,muscle,joint pain
• Leucocytosis
• Retinal hemorrhage
• Encephalopathy
• lymphangitis and lymphadenopathy.
• *It is not teratogenic
Contraindications & Cautions
• * Hypertension
• * Renal disease
* Patient with lymphangitis
IVERMECTIN
• Drug of choice for treatment of
strongyloidiasis
• Macrocyclic lactone ring
• Given only orally
• Rapidly absorbed
• Does not cross BBB.
• Half- life is 16 hrs
• Excretion is mainly in feces.
Mechanism Of Action
• Acts on the parasitte,
s glutamate-gated Cl-
channel receptors . Chloride influx increased ,
hyperpolarization occurs , resulting in
paralysis of the worm.
Or
• Paralyze nematodes by intensifying GABA-
mediated transmission of signals in peripheral
nerves.
Clinical uses
• Drug of choice for cutaneous larva migrans &
strongyloidiasis.
• Onchocerciasis
• It is also used for scabies , lice .
• Filariasis.
Adverse Effects
• Fatigue ,dizziness, GI disturbance
• Killing of microfilaria result in a Mazotti
reaction ( fever, headache, dizziness,
somnolence, hypotension , tachycardia,
peripheral edema……).
• Corneal opacities & other eye lesions.
Contraindications & Cautions
• Concomitant use with other drugs that
enhance GABA
e.g Barbiturates, bnzodiazepines, valproic acid.
• pregnancy
• Meningitis
• Children under 5 years of age.
BITHIONOL
• Drug of choice for the treatment of
fascioliasis ( sheep liver fluke)
• Pharmacokinetics:
• It is orally administered and excreted in urine.
Adverse Effects
• GI disturbance ( N., V., D., A.)
Dizziness, headache
Skin rashes , urticaria, Leucopenia
• Contraindications and precautions:
Hepatitis , leucopenia
Used with caution in children under 8 years of age.

More Related Content

PDF
Viral Pathogenesis.
PPT
sat. virus.ppt
PPTX
GENERAL PROPERTIES OF VIRUSES
DOC
Viruses. Methods of Indication & Identification. Diagnosis of Viral diseases
PPTX
Viral structure & properaties
PPT
General properties of viruses
PPT
01.02 biology of hiv
Viral Pathogenesis.
sat. virus.ppt
GENERAL PROPERTIES OF VIRUSES
Viruses. Methods of Indication & Identification. Diagnosis of Viral diseases
Viral structure & properaties
General properties of viruses
01.02 biology of hiv

What's hot (20)

PPT
Acinetobacter: Awakening of a sleeping demon
PDF
Virus morphology
PPTX
classification of virus :LHT,HOLMES,BALTIMORE,ICTV
PPT
Virus ppt
PPT
Classification, Morphology and Methods for the detection of Viruses
PPTX
Rabies virus
PPT
paramyxovirus.ppt
PPTX
Cultivation of viruses
PPTX
Viruses
PPTX
Viral replication
PPTX
Antibiotic resistance mechanism
PPTX
3. Virus lecture
PPTX
Retro virus
PPTX
Bacteriophage and replication
PPTX
Viral vaccines 2
PPTX
Virus structure and classification
PPTX
VIRUSES
PPTX
Mycoplasma
PPTX
Rhabdovirus lecture
PPTX
Acinetobacter: Awakening of a sleeping demon
Virus morphology
classification of virus :LHT,HOLMES,BALTIMORE,ICTV
Virus ppt
Classification, Morphology and Methods for the detection of Viruses
Rabies virus
paramyxovirus.ppt
Cultivation of viruses
Viruses
Viral replication
Antibiotic resistance mechanism
3. Virus lecture
Retro virus
Bacteriophage and replication
Viral vaccines 2
Virus structure and classification
VIRUSES
Mycoplasma
Rhabdovirus lecture
Ad

Viewers also liked (20)

PPT
Lecture 04.2014
PPT
Classes of antimicrobial agents
PPTX
Biosafety
PPT
Celebrating Kenya
PPT
Lecture 05.2014
PPT
Antibiotics Lecture 04
PPT
obesity diabetes and metabolic syndrome
PPT
Antibiotics Lecture 01
PPT
Molecular diagnostics
PPT
Msb 206. amino acid catab and fates of cs.2014
PPT
ANTIBIOTICS Lecture 05
PPTX
Mitosis Cell division and general genetics
PPT
Genetics PowerPoint
PPTX
Penicillin g production
PPT
Cells PowerPoint
PPT
Antibiotic History
PPT
Enzymes
PPT
Biochemistry PowerPoint
PPTX
Antibiotics & mechanisms of actions
Lecture 04.2014
Classes of antimicrobial agents
Biosafety
Celebrating Kenya
Lecture 05.2014
Antibiotics Lecture 04
obesity diabetes and metabolic syndrome
Antibiotics Lecture 01
Molecular diagnostics
Msb 206. amino acid catab and fates of cs.2014
ANTIBIOTICS Lecture 05
Mitosis Cell division and general genetics
Genetics PowerPoint
Penicillin g production
Cells PowerPoint
Antibiotic History
Enzymes
Biochemistry PowerPoint
Antibiotics & mechanisms of actions
Ad

Similar to Lecture 03.2014 (20)

PPT
4517 anti viral drugs1
PPT
3rd_antiviral_3.ppt
PPTX
AntiVirals Simpleslide presentation pharma
PPTX
Antiviral agents-1
PPTX
Antiviral Drugs & MOA Presentation .pptx
PPTX
Antiviral Drugs -1
PPTX
Antiviral drugs
PPTX
Antiviral agents
PPTX
Anti-viral Age bahhahyahhshsbhnts-961-.pptx
PPTX
Antiviral agents (2).pptx
PPTX
antiviral 1.pptxfkffjfjfjfjkfkffkffkfkfk
PPTX
Antiviral Drugs – Pharmacology III (B.Pharm)
PPTX
Anti Viral (1) (2).pptx
PPT
Antiviral drugs.ppt
PPTX
Antiviral drugs
PPTX
Antiviraldrugs
PPTX
Antiviral drugs
4517 anti viral drugs1
3rd_antiviral_3.ppt
AntiVirals Simpleslide presentation pharma
Antiviral agents-1
Antiviral Drugs & MOA Presentation .pptx
Antiviral Drugs -1
Antiviral drugs
Antiviral agents
Anti-viral Age bahhahyahhshsbhnts-961-.pptx
Antiviral agents (2).pptx
antiviral 1.pptxfkffjfjfjfjkfkffkffkfkfk
Antiviral Drugs – Pharmacology III (B.Pharm)
Anti Viral (1) (2).pptx
Antiviral drugs.ppt
Antiviral drugs
Antiviraldrugs
Antiviral drugs

More from Dr. Geoffrey K. K. Maiyoh (18)

PDF
Cancer in kenya
PPT
Lecture 01.2014
PPT
Mineralocorticoids & glucocorticoids
PPT
Dsb 106. intergration of metabolism.2014
PPT
Bpt 114. purine and pyrimidine metabolism
PPT
Msp 304. gsd,gout,a cuduria and lesh.2014
PPT
Cellular respiration (glycolysis, TCA and ETC)
PPT
Chemistry of Carbohydrates and Nucleic acids - An introduction
PPT
ANTIBIOTICS Lecture 06
PPT
Antibiotics Lecture 03
PPT
Gout,a cuduria les
PPT
Msb 203...cardio res sys.tg.pl.sl
PPT
Disorders of pyrimidine metabolism
PPT
Disorders of purine metabolism
PPT
Che 214 lecture 03
PPT
Che 214 lecture 02
PPT
Che 214 lecture 01
PPT
Che 214 lecture 04
Cancer in kenya
Lecture 01.2014
Mineralocorticoids & glucocorticoids
Dsb 106. intergration of metabolism.2014
Bpt 114. purine and pyrimidine metabolism
Msp 304. gsd,gout,a cuduria and lesh.2014
Cellular respiration (glycolysis, TCA and ETC)
Chemistry of Carbohydrates and Nucleic acids - An introduction
ANTIBIOTICS Lecture 06
Antibiotics Lecture 03
Gout,a cuduria les
Msb 203...cardio res sys.tg.pl.sl
Disorders of pyrimidine metabolism
Disorders of purine metabolism
Che 214 lecture 03
Che 214 lecture 02
Che 214 lecture 01
Che 214 lecture 04

Recently uploaded (20)

PPTX
Note on Abortion.pptx for the student note
DOCX
RUHS II MBBS Microbiology Paper-II with Answer Key | 6th August 2025 (New Sch...
PPTX
MANAGEMENT SNAKE BITE IN THE TROPICALS.pptx
PPT
MENTAL HEALTH - NOTES.ppt for nursing students
PDF
focused on the development and application of glycoHILIC, pepHILIC, and comm...
PPT
OPIOID ANALGESICS AND THEIR IMPLICATIONS
PPTX
anaemia in PGJKKKKKKKKKKKKKKKKHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHH...
PDF
Handout_ NURS 220 Topic 10-Abnormal Pregnancy.pdf
PPTX
DENTAL CARIES FOR DENTISTRY STUDENT.pptx
PPTX
Clinical approach and Radiotherapy principles.pptx
PPTX
History and examination of abdomen, & pelvis .pptx
PPTX
LUNG ABSCESS - respiratory medicine - ppt
PPTX
surgery guide for USMLE step 2-part 1.pptx
PPTX
Important Obstetric Emergency that must be recognised
PPTX
Respiratory drugs, drugs acting on the respi system
PPT
Breast Cancer management for medicsl student.ppt
PPT
genitourinary-cancers_1.ppt Nursing care of clients with GU cancer
PPTX
CEREBROVASCULAR DISORDER.POWERPOINT PRESENTATIONx
PPTX
CME 2 Acute Chest Pain preentation for education
PDF
Therapeutic Potential of Citrus Flavonoids in Metabolic Inflammation and Ins...
Note on Abortion.pptx for the student note
RUHS II MBBS Microbiology Paper-II with Answer Key | 6th August 2025 (New Sch...
MANAGEMENT SNAKE BITE IN THE TROPICALS.pptx
MENTAL HEALTH - NOTES.ppt for nursing students
focused on the development and application of glycoHILIC, pepHILIC, and comm...
OPIOID ANALGESICS AND THEIR IMPLICATIONS
anaemia in PGJKKKKKKKKKKKKKKKKHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHH...
Handout_ NURS 220 Topic 10-Abnormal Pregnancy.pdf
DENTAL CARIES FOR DENTISTRY STUDENT.pptx
Clinical approach and Radiotherapy principles.pptx
History and examination of abdomen, & pelvis .pptx
LUNG ABSCESS - respiratory medicine - ppt
surgery guide for USMLE step 2-part 1.pptx
Important Obstetric Emergency that must be recognised
Respiratory drugs, drugs acting on the respi system
Breast Cancer management for medicsl student.ppt
genitourinary-cancers_1.ppt Nursing care of clients with GU cancer
CEREBROVASCULAR DISORDER.POWERPOINT PRESENTATIONx
CME 2 Acute Chest Pain preentation for education
Therapeutic Potential of Citrus Flavonoids in Metabolic Inflammation and Ins...

Lecture 03.2014

  • 1. MBSM 713: BIOCHEMISTRY OF ANTI MICROBIAL AGENTS Lecture Three: 1.1.AntiviralsAntivirals 2.2.AntifungalsAntifungals 3.3.Antihelmitic drugsAntihelmitic drugs Dr. G. Kattam Maiyoh 01/23/15 GKM/KISIIU/MBSM713 /BIOC.AMIC.AGENS.LEC03 1
  • 3. Understanding VirusesUnderstanding Viruses They are different from other MicrobesThey are different from other Microbes Viral replicationViral replication • A virus cannot replicate on its own • It must attach to and enter a host cell • It then uses the host cell’s energy to synthesize DNA, RNA and protein. 01/23/15 GKM/KISIIU/MBSM713 /BIOC.AMIC.AGENS.LEC03 3
  • 4. Understanding VirusesUnderstanding Viruses Viruses are difficult to kill because they live inside the cells • Any drug that kills a virus MAY also kill cells 01/23/15 GKM/KISIIU/MBSM713 /BIOC.AMIC.AGENS.LEC03 4
  • 5. Anti-viral drugsAnti-viral drugs • Certain viruses multiply in the cytoplasm but others do in the nucleus • Most multiplication take place before diagnosis is made 01/23/15 GKM/KISIIU/MBSM713 /BIOC.AMIC.AGENS.LEC03 6
  • 6. Anti-Viral drugs • Many antiviral drugs are Purine or Pyrimidine analogs. • Many antiviral drugs are Prodrugs. They must be phosphorylated by viral or cellular enzymes in order to become active. • Most anti-viral agents inhibits active replication so the viral growth resumes after drug removal. 01/23/15 GKM/KISIIU/MBSM713 /BIOC.AMIC.AGENS.LEC03 7
  • 7. Antivirals how they act Key characteristics of antiviral drugs Able to enter the cells infected with virus Interfere with viral nucleic acid synthesis and/or regulation Some drugs interfere with ability of virus to bind to cells Some drugs stimulate the body’s immune system Best responses to antiviral drugs are in patients with competent immune systems A healthy immune system works synergistically with the drug to eliminate or suppress viral activity 01/23/15 GKM/KISIIU/MBSM713 /BIOC.AMIC.AGENS.LEC03 8
  • 8. Antiviral Medications Antiviral drugs  Used to treat infections caused by viruses other than HIV Antiretroviral drugs  Used to treat infections caused by HIV, the virus that causes AIDS 01/23/15 GKM/KISIIU/MBSM713 /BIOC.AMIC.AGENS.LEC03 9
  • 9. Antiviral Drugs: Nonretroviral Mechanism of action  Inhibit viral replication (Does not necessarily mean viral DNA replication.) Used to treat non-HIV viral infections  Influenza viruses  HSV (herpes simplex virus), VZV (vericella zoster virus)  CMV (cytomegalovirus)  Hepatitis A, B, C (HAV, HBV, NCV) Adverse Effects  Vary with each drug  Healthy cells are often killed also, resulting in serious toxicities 01/23/15 GKM/KISIIU/MBSM713 /BIOC.AMIC.AGENS.LEC03 10
  • 10. Anti-viral drugs • Current anti-viral agents do not eliminate non- replicating or latent virus • Effective host immune response remains essential for the recovery from the viral infection • Clinical efficacy depends on achieving inhibitory conc. at the site of infection within the infected cells 01/23/15 GKM/KISIIU/MBSM713 /BIOC.AMIC.AGENS.LEC03 11
  • 11. Anti-viral drugsAnti-viral drugs Stages of viral replication • Cell entry – attachment - penetration • Uncoating • Transcription of viral genome • Translation • Assembly of virion components • Release 01/23/15 GKM/KISIIU/MBSM713 /BIOC.AMIC.AGENS.LEC03 12
  • 13. Anti-viral drugs Anti-herpes virus agents • Acyclovir / Valacyclovir • Famciclovir / Penciclovir • Ganciclovir / Cidofovir • Foscarnet • Trifluridine / Idoxuridine / Vidarabine 01/23/15 GKM/KISIIU/MBSM713 /BIOC.AMIC.AGENS.LEC03 14
  • 14. • Valacyclovir is a prodrug of Acyclovir with better bioavailability. • Famciclovir is hydrolyzed to Penciclovir and has greatest bioavailability. • Penciclovir is used only topically whereas Famciclovir can be administered orally. 01/23/15 GKM/KISIIU/MBSM713 /BIOC.AMIC.AGENS.LEC03 15 Features
  • 15. PHARMACOLOGY OF ACYCLOVIR AND CONGENERS • Acyclovir, Valacyclovir, Ganciclovir, Famciclovir, Penciclovir • All are guanine nucleoside analogs. 01/23/15 GKM/KISIIU/MBSM713 /BIOC.AMIC.AGENS.LEC03 16
  • 16. Mechanism of action of Acyclovir and congeners : • All drugs are phosphorylated by a viral thymidine-kinase, then metabolized by host cell kinases to nucleotide analogs. • The analog inhibits viral DNA- polymerase • Only actively replicating viruses are inhibited 01/23/15 GKM/KISIIU/MBSM713 /BIOC.AMIC.AGENS.LEC03 17
  • 17. • Acyclovir is thus selectively activated in cells infected with herpes virus. • Uninfected cells do not phosphorylate acyclovir. 01/23/15 GKM/KISIIU/MBSM713 /BIOC.AMIC.AGENS.LEC03 18
  • 18. Mechanism of Action of Acyclovir 01/23/15 GKM/KISIIU/MBSM713 /BIOC.AMIC.AGENS.LEC03 19
  • 19. Antiviral spectrum : • Acyclovir: HSV-1, HSV-2, VZV, Shingles. • Ganciclovir / Cidofovir : CMV • Famciclovir : Herpes genitalis and shingles • Foscarnet : HSV, VZV, CMV, HIV • Penciclovir : Herpes labialis 01/23/15 GKM/KISIIU/MBSM713 /BIOC.AMIC.AGENS.LEC03 20
  • 20. Pharmacokinetics of Acyclovir : –Oral bioavailability ~ 20-30% –Distribution in all body tissues including CNS –Renal excretion: > 80% –Half lives: 2-5 hours –Administration: Topical, Oral , IV 01/23/15 GKM/KISIIU/MBSM713 /BIOC.AMIC.AGENS.LEC03 21
  • 21. Adverse effects of Acyclovir / Ganciclovir • Nausea, vomiting and diarrhea • Nephrotoxicity - crystalluria, haematuria, renal insufficiency • Myelosuppression – Neutropenia and thrombocytopenia – Ganciclovir 01/23/15 GKM/KISIIU/MBSM713 /BIOC.AMIC.AGENS.LEC03 22
  • 22. Therapeutic uses : Acyclovir is the drug of choice for: • HSV Genital infections • HSV encephalitis • HSV infections in immunocompromised patient Ganciclovir is the drug of choice for: • CMV retinitis in immunocompromised patient • Prevention of CMV disease in transplant patients CMV = Cytomegalovirus is a serious eye infection of the retina 01/23/15 GKM/KISIIU/MBSM713 /BIOC.AMIC.AGENS.LEC03 23
  • 23. Cidofovir : • It is approved for the treatment of CMV retinitis in immunocompromised patients • It is a nucleotide analog of cytosine – no phosphorylation required. • It inhibits viral DNA synthesis • Available for IV, Intravitreal inj, topical • Nephrotoxicity is a major disadvantage. 01/23/15 GKM/KISIIU/MBSM713 /BIOC.AMIC.AGENS.LEC03 24
  • 24. PHARMACOLOGY OF FOSCARNET • Foscarnet is an inorganic pyrophosphate analog   • It directly inhibits viral DNA and RNA -polymerase and viral reverse transcriptase (it does not require phosphorylation for antiviral activity) 01/23/15 GKM/KISIIU/MBSM713 /BIOC.AMIC.AGENS.LEC03 28
  • 25. Foscarnet • HSV-1, HSV-2, VZV, CMV and HIV. • Oral bioavailability ~ 10-20% • Distribution to all tissues including CNS • Administration: IV 01/23/15 GKM/KISIIU/MBSM713 /BIOC.AMIC.AGENS.LEC03 29
  • 26. Adverse effects of Foscarnet • Hypocalcemia and hypomagnesemia (due to chelation of the drug with divalent cations) are common. • Neurotoxicity (headache, hallucinations, seizures) • Nephrotoxicity (acute tubular nephrosis, interstitial nephritis) 01/23/15 GKM/KISIIU/MBSM713 /BIOC.AMIC.AGENS.LEC03 30
  • 27. Therapeutic uses of Foscarnet • It is an alternative drug for • HSV infections (acyclovir resistant / immunocompromised patient ) • CMV retinitis (ganciclovir resistant / immunocompromised patient ) 01/23/15 GKM/KISIIU/MBSM713 /BIOC.AMIC.AGENS.LEC03 31
  • 28. Respiratory viral infections Influenza – • Amantadine / Rimantadine • Oseltamivir / Zanamavir RSV bronchiolitis – • Ribavirin 01/23/15 GKM/KISIIU/MBSM713 /BIOC.AMIC.AGENS.LEC03 32
  • 29. Amantadine and Rimantadine : Influenza • Prevention & Treatment of influenza A • Inhibition of viral uncoating by inhibiting the viral membrane protein M2 • Amantadine has anti-parkinsonian effects. 01/23/15 GKM/KISIIU/MBSM713 /BIOC.AMIC.AGENS.LEC03 33
  • 30. Pharmacokinetics of Amantadine • Oral bioavailability ~ 50-90% • Amantadine cross extensively BBB whereas Rimantadine does not cross extensively . • Administration: Oral 01/23/15 GKM/KISIIU/MBSM713 /BIOC.AMIC.AGENS.LEC03 34
  • 31. Neuraminidase inhibitors : Influenza Oseltamivir / Zanamavir • Influenza contains an enzyme neuraminidase which is essential for the replication of the virus. • Neuraminidase inhibitors prevent the release of new virions and their spread from cell to cell. 01/23/15 GKM/KISIIU/MBSM713 /BIOC.AMIC.AGENS.LEC03 35
  • 32. Neuraminidase inhibitors : Influenza Oseltamivir / Zanamavir • These are effective against both types of influenza A and B. • Do not interfere with immune response to influenza A vaccine. • Can be used for both prophylaxis and acute treatment. Administration • Oseltamivir is orally administered. • Zanamavir is given intranasal. 01/23/15 GKM/KISIIU/MBSM713 /BIOC.AMIC.AGENS.LEC03 36
  • 33. Viru s       Diseases Drug(s) of choice Alternative drugs FLU A   Influenza Amantadine Rimantadine RSV Pneumonia, bronchiolitis Ribavirin (aerosol)   HSV   Genital herpes Acyclovir Foscarnet     Keratitis Conjunctivitis Trifluridine Idoxuridine Vidarabine   Encephalitis Acyclovir     Neonatal HSV infection Acyclovir Vidarabine   Herpes infections in immuno- compromised host Acyclovir Foscarnet 01/23/15 GKM/KISIIU/MBSM713 /BIOC.AMIC.AGENS.LEC03 48
  • 34. VZV     In normal host No therapy   In immunocompro- mised host, or during pregnancy Acyclovir Foscarnet CMV Retinitis Ganciclovir Foscarnet HIV AIDS HIV antibody positive with CD4 count < 500/mm3 Zidovudine ± protease inhibitors Didanosine, Stavudine HBV HCV Hepatitis B, C Interferons   01/23/15 GKM/KISIIU/MBSM713 /BIOC.AMIC.AGENS.LEC03 49
  • 35. Antiretroviral Drugs HAART - Highly active antiretroviral therapy • Includes at least three medications –“cocktails” • These medications work in different ways to reduce the viral load 01/23/15 GKM/KISIIU/MBSM713 /BIOC.AMIC.AGENS.LEC03 50
  • 36. Antiretroviral Drugs • Reverse transcriptase inhibitors (RTIs) – Block activity of the enzyme reverse transcriptase, preventing production of new viral DNA • Include: – Nucleoside RTIs (NRTIs) – Nonnucleoside RTIs (NNRTIs) – Nucleotide RTIs (NTRTIs) • Examples abacavir (Ziagen) delavirdine (Rescriptor) didanosine (Videx) lamivudine (Epivir) stavudine (Zerit) tenofovir (Viread) 01/23/15 GKM/KISIIU/MBSM713 /BIOC.AMIC.AGENS.LEC03 51
  • 37. Antiretroviral Drugs • Protease inhibitors (PIs) – Inhibit the protease a retroviral enzyme, preventing viral replication – Examples: amprenavir (Agenerase) indinavir (Crixivan) nelfinavir (Viracept) ritonavir (Norvir) saquinavir (Invirase) 01/23/15 GKM/KISIIU/MBSM713 /BIOC.AMIC.AGENS.LEC03 52
  • 38. Antiretroviral DrugsAntiretroviral Drugs • Fusion inhibitors – Inhibit viral fusion, preventing viral replication – Newest class of antiretroviral drugs – Example: enfuvirtide (Fuzeon) 01/23/15 GKM/KISIIU/MBSM713 /BIOC.AMIC.AGENS.LEC03 53
  • 39. Antiretroviral Drugs • Combinations of multiple antiretroviral medications are common • Adverse effects vary with each drug and may be severe−monitor for dose- limiting toxicities • Monitor for signs of opportunistic diseases 01/23/15 GKM/KISIIU/MBSM713 /BIOC.AMIC.AGENS.LEC03 54
  • 40. Antiretroviral Drugs:Antiretroviral Drugs: Adverse EffectsAdverse Effects  Numerous and varyNumerous and vary with each drugwith each drug Drug therapy may need to be modified because of adverse effects Goal is to find the regimen that will best control the infection with a tolerable adverse effect profile  Medication regimens change during the course of the illnessduring the course of the illness 01/23/15 GKM/KISIIU/MBSM713 /BIOC.AMIC.AGENS.LEC03 55 Antiviral DrugsAntiviral Drugs
  • 41. ANTIFUNGAL DRUGS Systemic & Topical Some are fungistatic, while others are fungicidal 01/23/15 56 GKM/KISIIU/MBSM713 /BIOC.AMIC.AGENS.LEC03
  • 42. Fungal Infection in Humans = Mycosis Fungal Infection in Humans = Mycosis • Major Types of Mycoses – superficial – cutaneous – subcutaneous – systemic – opportunistic • Symptoms vary from cosmetic to life threatening 01/23/15 57 GKM/KISIIU/MBSM713 /BIOC.AMIC.AGENS.LEC03
  • 43. Antifungal Agents • Polyene antibiotic • The polyene antibiotics bind with sterols in the fungal cell membrane, principally ergosterol. This causes the cell's contents to leak out and the cell dies. Animal cells contain cholesterol instead of ergosterol and so they are much less susceptible. – Nystatin – Amphotericin B (may be administered liposomally) – Natamycin – Rimocidin – Filipin – Pimaricin 01/23/15 58 GKM/KISIIU/MBSM713 /BIOC.AMIC.AGENS.LEC03
  • 44. Antifungal Agents Imidazole and triazole • The imidazole and triazole groups of antifungal drugs inhibit the enzyme cytochrome P450 14α- demethylase. This enzyme converts lanosterol to ergosterol, and is required in fungal cell membrane synthesis. These drugs also block steroid synthesis in humans. • Imidazoles: • Miconazole Bifonazole • Ketoconazole Butoconazole • Clotrimazole Econazole • Mebendazole Fenticonazole • Isoconazole Oxiconazole • Sertaconazole Sulconazole • Thiabendazole Tiaconazole01/23/15 60 GKM/KISIIU/MBSM713 /BIOC.AMIC.AGENS.LEC03
  • 45. Antifungal Agents • The triazoles are newer, and are less toxic and more effective: • Fluconazole • Itraconazole • Ravuconazole • Posaconazole • Voriconazole 01/23/15 61 GKM/KISIIU/MBSM713 /BIOC.AMIC.AGENS.LEC03
  • 46. Antifungal Agents Allylamines • Allylamines inhibit the enzyme squalene epoxidase, another enzyme required for ergosterol synthesis: – Terbinafine - marketed as Lamisil – Amorolfine – Naftifine – Butenafine 01/23/15 62 GKM/KISIIU/MBSM713 /BIOC.AMIC.AGENS.LEC03
  • 47. Antifungal Agents Echinocandin • Echinocandins inhibit the synthesis of glucan in the cell wall, probably via the enzyme 1,3-β glucan synthase: – Anidulafungin – Caspofungin – Micafungin 01/23/15 63 GKM/KISIIU/MBSM713 /BIOC.AMIC.AGENS.LEC03
  • 48. Antifungal Agents • Others: –Flucytosine is an antimetabolite. –Griseofulvin binds to polymerized microtubules and inhibits fungal mitosis; It is derived from the mold Penicillium griseofulvum. –Fluocinonide –Salicylic Acid (topical) –Tinactin or Tolnaftate –Potassium Iodide 01/23/15 64 GKM/KISIIU/MBSM713 /BIOC.AMIC.AGENS.LEC03
  • 50. Helminth Infections 1-Tapeworms ( cestodes) Beef tapeworm / fish tapeworm 2- Intestinal round worms ( nematodes) Ascaris, pinworm ,whipworm, strongyloides, ancylostoma ( hookworm ). A skin infection is termed cutaneous larva migrans
  • 51. Mechanism of action • May act by causing : • 1- paralysis of the worm. • 2- damaging the worm leading to partial digestion or rejection by immune mechanisms. • 3- interfere with the metabolism of the worm. *Worms or larvae live in tissues of host body like muscles , viscera , menninges , subcutaneous tissues.
  • 52. • Adult filariae live in the lymphatics, connective tissue or mesentery of host and produce live embryos or microfilariae, which goes to blood stream. • They are ingested by mosquitoes or similar insects, they develop to larvae this secondary host and pass to mouth parts of insect and re-injected to humans
  • 53. Ascaris lumbricoids ( common round worm)
  • 54. ANTHELMINTIC DRUGS ALBENDAZOLE • Broad spectrum oral anthelmintic • Drug of choice for treatment of hydatid disease (tapeworm) and cysticercosis (pork tapeworm) • It is also used for the treatment of ascariasis ,tricurasis and strongyloidiasis, pinworm, hookworm
  • 55. Mechanism Of Action 1. Inhibits microtubule synthesis by binding to β – tubulin. 2. Inhibits mitochondrial reductase causing reduced glucose transport. Intestinal parasites are immobilized and die slowly. • Larvicidal in hydatid ,cysticercosis , ascariasis and hook worm infections. • Ovicidal in ascariasis, hookworm ,trichuriasis
  • 56. Pharmacokinetics • Formulated as Benzimidazole carbamate • Administered orally , absorption increased with a fatty meal • Metabolized in the liver to the active metabolite called albendazole sulfoxide
  • 57. Pharmacokinetics • Plasma half life is 8-12 hours • sulfoxide is mostly protein bound distributes well to tissues and enters bile,CSF & hydatid cysts. • Metabolites are excreted in urine
  • 58. Clinical uses • Used on empty stomach when used against intraluminal parasites but with a fatty meal when used against tissue parasites. 1. In ascariasis ,trichuriasis ,hookworm, pin worm infections : 2. Hydatid diseases
  • 59. Albendazole (con’) 3. Neurocysticercosis: Used with corticosteroid to decrease the inflammation caused by dying organism and it also reduces the duration of course for 21 days 4. Other infections: Drug of choice in cutaneous and visceral larva migrans , intestinal capillariasis, giardiasis & taeniasis.
  • 60. Adverse Effects • In short term(1-3 days): Mild epigastric pain,diarrhea, nausea, headache & insomnia. • In long term use : for hydatid cyst and cysticercosis : abdominal pain, headache ,fever ,fatigue, alopecia , increased liver enzymes , pancytopenia. Blood counts and liver enzymes should be followed. • Not given during pregnancy, hypersensitive people to benzimidazole drugs & children under 2 years .
  • 61. PYRANTEL PAMOATE • Broad spectrum • Pharmacokinetics: – Poorly absorbed from GIT – Half of the drug is excreted unchanged in the feces. • Mechanism of action: – result in paralysis of worms. It is a neuromuscular blocking agent Efficacy – Very effective against luminal organisms( mature or immature forms). – Not effective against migratory stages in the tissues or against ova
  • 62. Clinical uses • Pin worm given orally with or without food. • Ascariasis • Hookworm Pinworm male ,female
  • 63. Adverse Effects Infrequent mild transient GI disturbance – Drowsiness , headache ,insomnia. – Rash ,fever Contraindications & Cautions – Should be used with caution in liver dysfunction. – Pregnancy – Children under 2 years of age
  • 64. PIPERAZINE • Only recommended for the treatment of ascariasis • Cure rate 90% for 2 days treatment. • Readily absorbed orally and excreted mostly unchanged in urine • Mechanism of action: Causes paralysis of ascaris by blocking acetylcholine at myoneural junction , the live worms expelled by normal peristalsis. • Treatment • Treatment is continued for 3-4 days or repeated after one week in case of heavy infections.
  • 65. Adverse Effects • GI disturbance • Neurotoxicity ,allergic reactions . • Contraindications • Epilepsy or a history of epilepsy • Impaired liver or kidney functions • pregnancy • Chronic neurologic disease
  • 66. NICLOSAMIDE • Second-line drug for treatment of most tapeworm infections. • Mechanism of action: • Adult worm( not ova) is rapidly killed by inhibition of oxidative phosphorylation . • Pharmacokinetics: • Poorly absorbed from gut & excreted in urine.
  • 67. Clinical Uses • Treatment of most forms of tapeworms. • Not effective against cysticercosis or hydatic disease. • Given in the morning on empty stomach. • Purgative is necessary to purge all dead segments& prevent liberation of ova.
  • 68. Adverse effects & Contraindications • Mild ,infrequent and transitory GI disturbance • Alcohol consumption should be avoided • Not indicated in children under 2 years of age or in pregnancy.
  • 69. DIETHYL CARBAMAZINE • Drug of choice for the treatment of filariasis and tropical eosinophilia. • Pharmacokinetics: • Rapidly absorbed from gut • Half- life is 2-3 hours • The drug should be given after meals • It is excreted in urine as unchanged or metabolite. • Dosage is reduced in urinary alkalosis and renal impairment.
  • 70. Mechanism Of Action • Immobilizes microfilariae and alters their surface structure ,displacing them from tissues & making them susceptible to destruction by host defense mechanism • It has immunosuppressive effects
  • 71. Adverse Effects • Fever , malaise, papular rash, headache, GI disturbance,cough. Chest,muscle,joint pain • Leucocytosis • Retinal hemorrhage • Encephalopathy • lymphangitis and lymphadenopathy. • *It is not teratogenic
  • 72. Contraindications & Cautions • * Hypertension • * Renal disease * Patient with lymphangitis
  • 73. IVERMECTIN • Drug of choice for treatment of strongyloidiasis • Macrocyclic lactone ring • Given only orally • Rapidly absorbed • Does not cross BBB. • Half- life is 16 hrs • Excretion is mainly in feces.
  • 74. Mechanism Of Action • Acts on the parasitte, s glutamate-gated Cl- channel receptors . Chloride influx increased , hyperpolarization occurs , resulting in paralysis of the worm. Or • Paralyze nematodes by intensifying GABA- mediated transmission of signals in peripheral nerves.
  • 75. Clinical uses • Drug of choice for cutaneous larva migrans & strongyloidiasis. • Onchocerciasis • It is also used for scabies , lice . • Filariasis.
  • 76. Adverse Effects • Fatigue ,dizziness, GI disturbance • Killing of microfilaria result in a Mazotti reaction ( fever, headache, dizziness, somnolence, hypotension , tachycardia, peripheral edema……). • Corneal opacities & other eye lesions.
  • 77. Contraindications & Cautions • Concomitant use with other drugs that enhance GABA e.g Barbiturates, bnzodiazepines, valproic acid. • pregnancy • Meningitis • Children under 5 years of age.
  • 78. BITHIONOL • Drug of choice for the treatment of fascioliasis ( sheep liver fluke) • Pharmacokinetics: • It is orally administered and excreted in urine.
  • 79. Adverse Effects • GI disturbance ( N., V., D., A.) Dizziness, headache Skin rashes , urticaria, Leucopenia • Contraindications and precautions: Hepatitis , leucopenia Used with caution in children under 8 years of age.

Editor's Notes

  • #15: Trifluridine
  • #25: Fomivirsen : CMV It is an antisense oligonucleotide against CMV m-RNA. It is limited to CMV retinitis who fail to other therapies.
  • #59: The antifungal agents that are used are listed in this particular slide. Amphotericin B and Liposomal Amphotericin B will be discussed as well as the azoles that are listed on this slide. Nystatin is also used primarily as a topical agent for different uses. Finally Flucytosine is used adjunctively in addition to some other agents for systemic fungal infection.
  • #61: The antifungal agents that are used are listed in this particular slide. Amphotericin B and Liposomal Amphotericin B will be discussed as well as the azoles that are listed on this slide. Nystatin is also used primarily as a topical agent for different uses. Finally Flucytosine is used adjunctively in addition to some other agents for systemic fungal infection.
  • #63: The antifungal agents that are used are listed in this particular slide. Amphotericin B and Liposomal Amphotericin B will be discussed as well as the azoles that are listed on this slide. Nystatin is also used primarily as a topical agent for different uses. Finally Flucytosine is used adjunctively in addition to some other agents for systemic fungal infection.
  • #64: The antifungal agents that are used are listed in this particular slide. Amphotericin B and Liposomal Amphotericin B will be discussed as well as the azoles that are listed on this slide. Nystatin is also used primarily as a topical agent for different uses. Finally Flucytosine is used adjunctively in addition to some other agents for systemic fungal infection.
  • #65: The antifungal agents that are used are listed in this particular slide. Amphotericin B and Liposomal Amphotericin B will be discussed as well as the azoles that are listed on this slide. Nystatin is also used primarily as a topical agent for different uses. Finally Flucytosine is used adjunctively in addition to some other agents for systemic fungal infection.