AA Pharma Imipramine Overdosage

Symptoms: High doses may cause temporary confusion, disturbed concentration, transient visual hallucinations, agitation, hyperactive reflexes, muscle rigidity, vomiting, or hyperpyrexia, in addition to anything listed under Adverse Reactions. Based on imipramine's known pharmacologic actions, overdosage may cause drowsiness, hypothermia, tachycardia and other arrhythmic abnormalities such as bundle branch block, ECG evidence of impaired conduction and congestive heart failure. Other manifestations may be dilated pupils, convulsions, severe hypotension, stupor and coma. All patients suspected of having taken an overdose should be admitted to a hospital as soon as possible.
Treatment: is symptomatic and supportive.
Empty the stomach as quickly as possible by emesis followed by gastric lavage. Following gastric lavage activated charcoal (30g) may be administered every four to six hours during the first 24 hours after ingestion.
Monitor cardiac function for any signs of dysrhythmia.
Maintain an open airway and adequate fluid intake; regulate body temperature.
Use standard medical measures to manage circulatory shock and metabolic acidosis. Cardiac arrhythmias may be treated with neostigmine, pyridostigmine, or propranolol. If signs of cardiac failure occur, consider the use of a short acting digitalis preparation. Close monitoring of cardiac function for not less than 5 days is advisable.
Anticonvulsants may be given to control seizures.
Dialysis is of no value because of low plasma concentrations of the drug.
Since overdosage is often deliberate, patients may attempt suicide by other means during the recovery phase. Deaths by deliberate or accidental overdosage have occurred with this class of drugs.
Pyridostigmine given i.v. can be used to reverse the symptoms of tricyclic antidepressant poisoning.
Give physostigmine 1 to 3 mg slow i.v. (over 2 minutes). If no clinical changes or cholinergic signs occur within 15 to 30 minutes, an additional 1 to 2 mg may be administered. Repeated doses of 1 to 2 mg i.v. every 30 minutes up to two hours.
Physostigmine is not innocuous and carries the risk of inducing seizures and cholinergic crisis. It should not be used routinely. If excessive sweating, nausea or vomiting occur, reduce dosage of physostigmine. Atropine in a dose of 50% of the amount of injected physostigmine should be kept on hand and administered if excessive cholinergic symptoms develop.