Olanzapine Oral: Dosing and Safety

Therapeutic action

Atypical antipsychotic.

Indications

Acute and chronic psychosis and acute manic episode, in the event of intolerance or treatment failure with other antipsychotics.

For these indications, haloperidol is preferred when suitable.

Forms and strengths

• 2.5 mg, 5 mg, and 10 mg tablets.

Dose

• Adult: 10 mg once daily. Increase up to 15 mg daily if necessary, with a maximum of 20 mg daily.
• Reduce the dose by half in older patients, with a maximum of 10 mg daily.

Duration

Acute psychosis: at least 3 months.

Chronic psychosis: at least one year.

Manic episode: 8 weeks after remission of symptoms.

Discontinue treatment gradually over 4 weeks. If signs of relapse occur, increase the dose then decrease it more gradually.

Contra-indications, adverse effects, precautions

• Do not administer to patients with cardiac disorders, dementia such as Alzheimer's disease, Parkinson's disease, history of neuroleptic malignant syndrome, or closed-angle glaucoma.
• Administer with caution and carefully monitor use in older patients and patients with hypokalaemia, hypotension, prostate disorders, renal impairment, hepatic impairment, or history of seizures.
• May cause orthostatic hypotension, drowsiness, extrapyramidal symptoms, hyperprolactinaemia, weight gain, hyperlipidaemia, hyperglycaemia, anticholinergic effects, headache, insomnia, dizziness, sexual dysfunction, and rarely neuroleptic malignant syndrome requiring immediate discontinuation.
• In case of extrapyramidal symptoms, try reducing the dose of olanzapine or, if symptoms are severe, add biperiden or trihexyphenidyl.
• Avoid or monitor combination with central nervous system depressants, ciprofloxacin, carbamazepine, rifampicin, phenobarbital, phenytoin, ritonavir, antihypertensives, and drugs that prolong the QT interval.
• Avoid alcohol during treatment.
• Pregnancy: re-evaluate whether treatment is still necessary. If continued, use the lowest effective dose and observe the neonate if exposure occurred in the third trimester. If treatment starts during pregnancy, preferably use haloperidol.
• Breast-feeding: if absolutely necessary, do not exceed 10 mg daily.