Risperidone

Therapeutic action

• Atypical antipsychotic

Indications

• Acute and chronic psychosis and acute manic episode, in the event of intolerance or treatment failure with other antipsychotics (preferably use haloperidol for these indications)

Forms and strengths

• 1 mg and 2 mg tablets

Dosage

Acute or chronicpsychosis

• Adult: 1 mg 2 times daily. Gradually increase up to 3 mg 2 times daily if necessary(max. 10 mg daily).

Acute manic episode

• Adult: 2 mg once daily. Increase in increments of 1 mg per week if necessary (max. 6 mg daily).

Reduce the dose by half (initial dose and increments) in older patients and in patients with hepatic or renal impairment (max. 4 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 (heart failure, recent myocardial infarction, conduction disorders, bradycardia, etc.), dementia (e.g. Alzheimer's disease), Parkinson's disease and history of neuroleptic malignant syndrome.
• Administer with caution and carefully monitor use in older patients, patients with hypokalaemia, hypotension, renal or hepatic impairment, history of seizures.
• May cause: drowsiness (cautionwhen driving/operating machinery), insomnia,headache, extrapyramidal symptoms, agitation, anxiety, orthostatic hypotension, weight gain, hyperprolactinaemia, sexual dysfunction; neuroleptic malignant syndrome(unexplained hyperthermia with neuromuscular disorders), rare but requiring immediate treatment discontinuation.
• In case of extrapyramidal symptoms, try reducing the dose of risperidone or, if the extra pyramidal symptoms are severe, add biperiden or trihexyphenidyl.
• Avoid or monitor combination with:
  • central nervous system depressants (opioid analgesics, sedatives, H1 antihistamines, etc.); 
  • fluoxetine, paroxetine, sertraline, verapamil (increased plasma concentrations of risperidone); 
  • carbamazepine, rifampicin, phenobarbital, phenytoin (decreased plasma concentrations of risperidone);
  • antihypertensive drugs (risk of hypotension); drugs that prolong the QT interval (amiodarone, chloroquine, erythromycin, fluconazole, mefloquine, pentamidine, quinine, etc.).
• Avoid alcohol during treatment(increased risk of adverse effects).
• Pregnancy: re-evaluate whether the treatment is still necessary; if it is continued, use the lowest effective dose. Observe the neonate the first few days (risk of agitation, tremors,hypertonia/hypotonia, respiratory difficulties, sleeping disorders, etc.) if the mother was under treatmentin the 3rd trimester. If treatment starts during pregnancy, preferably use haloperidol.
• Breast-feeding: if absolutely necessary,do not exceed 6 mg daily.

Storage

– Below 25 °C