Risperdal (risperidone)

Use: Antipsychotic agent. Acute treatment and maintenance therapy in schizophrenia and related psychotic disorders: Adults: Therapy may be started on either a once-or-twice-daily schedule, generally with 1-2 mg/day. Adjust the dose gradually over several days to a target dose of 4-6 mg/day. If indicated, make further dosage adjustments (i.e. +/- 1 mg) at intervals of not less than 1 week. Safety of Risperdal not established neither above 16 mg total daily dose, administered twice daily nor beyond a single dose of 8 mg once daily.

Elderly schizophrenia patients: Adjust slowly from a 0.25 mg twice-daily starting dose to a maximum daily dosefo3 mg. To maintain remission, use the lowest effective dose and reassess patients periodically to determine the need for ongoing therapy.

Patients prone to hypotension: Consider a starting dose of 0.25-0.5 mg twice daily.

Impaired liver function: Initially, 0.25-0.5 mg twice daily, adjusted in 0.5 mg twice-daily increments to 1-2 mg twice daily.

Behavioural disturbances in severe dementia: Geriatrics: Start with 0.25 mg twice daily, increasing by 0.25 mg increments per day every 2-4 days until the optimal dose is reached. The optimal dose of 0.5 mg twice daily (maximum: 1 mg twice daily).

Precautions: Hepatic or renal disease, parkinsonian patients. Cardiovascular disease (orthostatic hypotension and tachycardia, especially during the initial dose titration period and the first few weeks of treatment). Neuroleptic malignant syndrome, tardive dyskinesia. CBA including stroke and TIA (elderly patients). Priapism. Hyperglycemia. Hyperprolactinemia. Antiemetic effect. History of seizures. Pregnancy. Lactation (breast-feeding is not recommended). Suicide. Disruption of body temperature regulation. Safety/efficacy in children < 18 years not established.

Side effects: Insomnia, agitation, extrapyramidal disorder, anxiety, headache, rhinitis, weight gain (mean 2-3 kg) during long-term therapy. Rarely, hypotension, syncope, cardiac arrhythmias, first degree AV-block, seizure, gynecomastia, galactorrhea, amenorrhea, menorrhagia, ejaculatory and erectile dysfunction.

Interactions: May enhance the effects of alcohol, centrally-acting drugs, hypotensive agents; may antagonize the effects of levodopa and dopamine agonists. Hepatic enzyme-inducing drugs (monitor). Concomitant administration of fluoxetine may increase the plasma concentrations of risperidone by 2- to 3-fold, while the concentration of the major active metabolite is increased by about 50%.

Patient tips: Caution regarding driving/operating machinery, gradual discontinuation of previous treatment on switching from other antipsychotics. Report immediately any signs/symptoms of CVS. Do not take oral solution with cola or tea. M-Tabs: Protect from moisture. Do not break or divide. Allow to dissolve on tongue and then swallow (with water, if desired).

Supplied: 0.25 mg, 0.5 mg, 1 mg, 2 mg, 3 mg, 4 mg tablets; 1 mg/mL oral solution, 30 mL bottles. Also available: 0.5 mg, 1 mg and 2 mg Risperdal M-Tabs (orally disintegrating tablets).