Tegretol Overdosage

Symptoms and signs: The presenting symptoms of overdosage usually involve the central nervous, cardiovascular and respiratory systems, and the adverse drug reactions mentioned under Adverse Reactions.
Central nervous system: CNS depression; disorientation, depressed level of consciousness, somnolence, agitation, hallucinations, coma; blurred vision, slurred speech, dysarthria, nystagmus, ataxia, dyskinesia; hyperreflexia followed by hyporeflexia; convulsions, psychomotor disturbances, myoclonus, hypothermia, mydriasis.
Respiratory tract: Respiratory depression, pulmonary oedema.
Cardiovascular system: Tachycardia, hypotension, occasionally hypertension, conduction disturbances with widening of QRS complex; syncope in association with cardiac arrest.
Gastrointestinal tract: Vomiting, delayed gastric emptying, reduced bowel motility.
Musculoskeletal system: Cases of rhabdomyolysis have been reported in association with carbamazepine toxicity.
Renal function: Urinary retention, oliguria or anuria; fluid retention, water intoxication due to an ADH-like effect of carbamazepine.
Laboratory findings: Hyponatraemia, (possible) metabolic acidosis, (possible) hyperglycaemia, elevated levels of muscle creatine phosphokinase.
Management: There is no specific antidote.
Management should initially be determined by the patient's clinical condition. The patient should be hospitalized. Determination of plasma concentrations to confirm carbamazepine intoxication and ascertain the size of the overdose.
Gastric evacuation, gastric lavage and administration of activated charcoal. Delayed gastric emptying may result in delayed absorption, leading to relapse during recovery from intoxication.
Supportive medical care in an intensive care unit, with cardiac monitoring and careful correction of electrolyte imbalance.
Special recommendations: Charcoal haemoperfusion has been recommended. Haemodialysis is an effective treatment modality in the management of carbamazepine overdose.
Relapse and aggravation of symptoms should be anticipated on the second and third days following overdosage due to delayed absorption.