Fluoxetine Overdose

10 OVERDOSAGE Olanzapine and fluoxetine capsules — During premarketing clinical studies of olanzapine and fluoxetine in combination, overdose of both fluoxetine and olanzapine were reported in 5 study subjects.

Four of the 5 subjects experienced loss of consciousness or coma .

No fatalities occurred.

Adverse reactions involving overdose of fluoxetine and olanzapine in combination, and olanzapine and fluoxetine capsules, have been reported.

An overdose of combination therapy is defined as confirmed or suspected ingestion of a dose of >20 mg olanzapine in combination with a dose of >80 mg fluoxetine.

Adverse reactions associated with these reports included somnolence (sedation), impaired consciousness (coma), impaired neurologic function (ataxia, confusion, convulsions, dysarthria), arrhythmias, lethargy, essential tremor, agitation, acute psychosis, hypotension, hypertension, and aggression.

Fatalities have been confounded by exposure to additional substances including alcohol, thioridazine, oxycodone, and propoxyphene.

Olanzapine — In postmarketing reports of overdose with olanzapine alone, symptoms have been reported in the majority of cases.

In symptomatic patients, symptoms with ≥10% incidence included agitation/aggressiveness, dysarthria, tachycardia, various extrapyramidal symptoms, and reduced level of consciousness ranging from sedation to coma.

Among less commonly reported symptoms were the following potentially medically serious reactions: aspiration, cardiopulmonary arrest, cardiac arrhythmias (such as supraventricular tachycardia as well as a patient that experienced sinus pause with spontaneous resumption of normal rhythm), delirium, possible neuroleptic malignant syndrome, respiratory depression/arrest, convulsion, hypertension, and hypotension.

Reports of fatality in association with overdose of olanzapine alone.

In 1 case of death, the amount of acutely ingested olanzapine was reported to be possibly as low as 450 mg of oral olanzapine; however, in another case, a patient was reported to survive an acute olanzapine ingestion of approximately 2 g of oral olanzapine.

Fluoxetine — The following have been reported with fluoxetine overdosage: Seizures, which may be delayed, and altered mental status including coma.

Cardiovascular toxicity, which may be delayed, including QRS and QTc interval prolongation, wide complex tachyarrhythmias, Torsade de Pointes, and cardiac arrest.

Hypertension most commonly seen, but rarely can see hypotension alone or with co-ingestants including alcohol.

Serotonin syndrome (patients with a multiple drug overdosage with other pro-serotonergic drugs may have a higher risk).

10.1 Management of Overdose For current information on the management of olanzapine and fluoxetine capsules (olanzapine and fluoxetine) overdose, consider contacting a Certified Poison Control Center (1-800-222-1222) or a medical toxicologist for additional overdosage management recommendations.

In managing overdose, consider the possibility of multiple drug involvement.

Establish and maintain an airway and ensure adequate ventilation.

Commence cardiovascular monitoring immediately and include continuous electrocardiographic monitoring to detect possible arrhythmias.

A specific precaution involves patients who are taking or have recently taken olanzapine and fluoxetine capsules and may have ingested excessive quantities of a TCA (tricyclic antidepressant).

In such cases, accumulation of the parent TCA and/or an active metabolite increases the possibility of serious sequelae and extends the time needed for close medical observation.

Due to the large volume of distribution of olanzapine and fluoxetine, forced diuresis, dialysis, hemoperfusion, and exchange transfusion are unlikely to be of benefit.

No specific antidote for either fluoxetine or olanzapine overdose is known.