Management protocol for theophylline intoxication
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This document provides guidelines for managing intoxication from theophylline, a bronchodilator. Key points include: 1. Theophylline has a narrow therapeutic index and toxicity can occur even at low doses, presenting with nausea, vomiting, tachycardia, seizures and coma. 2. Initial treatment focuses on stabilizing vital signs and eliminating the drug through induction of vomiting, gastric lavage or activated charcoal. Hemodialysis may be needed for severe cases. 3. Patients with seizures, coma, cardiac issues or high initial blood levels require ICU admission for close monitoring and management of arrhythmias or acidosis. Serial blood levels guide further treatment.
Management protocol for theophylline intoxication
- 1. Management protocol for intoxication By Kerolus Ekram Gad Shehata • PGY-III IM resident, Ain Shams University • ECFMG certified
- 2. General Hints Frequency: Very common Mode: Accidental & Suicidal Preparations: Epicophylline, Aminophylline, Theo SR, Quibron SR…etc. “Anti-asthmatics” Presentation: Acute or acute on top of chronic toxicity. Characteristic shape of the tablet: rectangular, dividable.
- 4. Presentation • Generally: Any patient with severe intractable vomiting + Tachycardia in the PCC ER unit = Theophylline toxicity till proved otherwise. • GIT: nausea, severe up to intractable vomiting +/- upper GI bleeding, diarrhea and abdominal pain. • CVS: palpitation and hypotension • CNS: Tremors, agitation, restlessness, seizures and coma in late severe stages. • Respiratory: Tachypnea
- 5. Take Care!! • Theophylline has narrow TI. • Some preparations may form concretions in the stomach especially with the sustained release preparations. • Theophylline undergoes significant entero- hepatic circulation…MDAC • Toxicity can occur in low doses in patients taking theophylline chronically.
- 6. How to proceed? • Vitals are Vital. • Pulse: Tachycardic +/- irregularity • B.P.: Hypotension. • R.R.: Tachypneic. • N.B. once symptomatic = Admission • Stabilizing the patient’s condition is our first priority before inquiring about the detailed history. • Seizing patient should be treated promptly with BZP and we may use phenobarbital or Thiopental if needed.
- 7. How to proceed...Cont’d • GI elimination is of utmost importance. • Ipecac is not preferred as the patient may already have intractable vomiting. • We can just give plenty amount of water to induce vomiting unless it is contraindicated e.g. comatosed patient, severely shocked patient, history of upper GI bleeding. • Elimination should never be skipped even if the presentation is delayed esp. with SR tablets.
- 8. How to proceed...Cont’d • Gastric lavage can be done in uncooperative patients or in patients with DCL. • Activated charcoal is a cornerstone in our management plan and should be given in multiple doses as a GI dialysis. • In severe intractable vomiting: Metoclopramide up to Ondansetron. • N.B. Never to use phenothiazines as antiemetics as they decrease threshold of seizures. • Hypotension: Crystalloids, colloids or even vasopressors e.g. NEp.
- 9. Severe cases • N.B. Severely agitated patients, seizing patients or those with history of seizures, comatosed patients: That indicate severe toxicity and we can resort to hemodialysis immediately after initial stabilization of the patients even before admission. • N.B. Extremes of age, patients chronically treated with theophylline and those with other premorbid conditions are more susceptible to severe toxicity.
- 10. Investigations • Routine lab: Glucose, Na, K • Glucose: Hyperglycemia (usually well tolerated) • Potassium: HYPOkalemia due to many causes (catecholamine release, severe vomiting, respiratory alkalosis). So, it is actually PESUDOhypokalemia that shouldn’t be treated aggressively as it will be spontaneously corrected (redistribution process). • ABG: Metabolic acidosis (correlate with the severity of the condition) + Respiratory alkalosis.
- 11. Investigations…Cont’d • ECG on admission and repeated thereafter: Tachyarrhythmias are common (atrial and ventricular) • Continuous cardiac monitoring is needed in severely intoxicated patients and those with premorbid cardiac conditions. • Theophylline blood level: we should have a baseline value on admission and repeated later on to follow up case progression. • CPK: if you suspect rhabdomyolysis (repeatedly seizing patient)
- 12. What is next? • Serial follow up of the patient’s vital data, clinical progression and laboratory studies is of a great significance to determine if further therapeutic protocol is needed. • N.B. Severely intoxicated patients may present with severe agitation that can be easily mistaken by the inexperienced ER physicians as a psychic patients in the mean time that she needs immediate hemodialysis.
- 13. What is next? • Management strategies for theophylline intoxication include supportive care, administration of multiple- dose activated charcoal, and, in severe cases, hemodialysis. • N.B. The major life-threatening events of theophylline intoxication are seizures and cardiac arrhythmias. • Management of Metabolic acidosis: NaHCO3 + serial ABG monitoring. • For hyperthermia: Cold fomentations +/- BZP to calm the patient down
- 14. Indications of ICU ADMISSION 1. Unstable vital data despite initial ER management. 2. Severe agitation +/- Seizures. 3. History of convulsions. 4. Comatosed patients. 5. Severe metabolic acidosis. 6. Premorbid condition e.g. cardiac patients 7. ECG shows potentially dangerous arrhythmias e.g. multiple PVCs. 8. Initial blood level > 35 microgram/dl.
- 15. Special Notes • For atrial Tachyarrhythmias: we can use propranolol (unless there is bronchospasm), esmolol or verapamil. • For Ventricular arrhythmias : use lidocaine. • Phenytoin is ineffective in theophylline induced seizures and actually been shown to decrease the seizure threshold and lower the lethal dose (Enzyme inhibitor just like Macrolides) • Never use phenothiazines as antiemetics as they may induce seizures in these patients.