Risperidone

A to Z Drug Facts

 Action Has antipsychotic effect, apparently caused by dopamine and serotonin receptor blocking in CNS.

 Indications Management of psychotic disorders.

 Contraindications Standard considerations.

 Route/Dosage

Adults: PO 1 mg bid on first day, 2 mg bid on second day, and 3 mg bid on third day. Dosage adjustment thereafter should occur at intervals of at least 1 wk in increments of 1 mg bid. Maximum effect generally occurs in a range of 4 to 8 mg/day (max, 16 mg/day).

Renal or Hepatic Impairment

Elderly: PO 0.5 mg bid initially; increase in 0.5 mg increments bid thereafter.

 Interactions

Alcohol, CNS depressants: May cause additive CNS depressant effects. Antihypertensives: Risperidone may enhance hypotensive effects of some antihypertensives. Carbamazepine: May decrease risperidone plasma levels. Clozapine, paroxetine: May increase risperidone plasma levels. Levodopa: The effects of levodopa may be antagonized.

 Lab Test Interferences None well documented.

 Adverse Reactions

CARDIOVASCULAR: Orthostatic hypotension; tachycardia; palpitations; hypertension; cardiac arrhythmias; syncope; angina pectoris; lightheadedness; ECG changes. CNS: Tardive dyskinesia; extrapyramidal symptoms such as pseudoparkinsonism, akathisia, and dystonias; drowsiness; increased sleep duration; headache; insomnia; agitation; anxiety; aggressive reaction; dizziness; seizure. DERMATOLOGIC: Rash; dry skin; seborrhea; photosensitivity. EENT: Abnormal vision/accommodation; tinnitus; rhinitis; sinusitis; pharyngitis. GI: Constipation; nausea; dyspepsia; vomiting; abdominal pain; increased salivation; toothache; anorexia; reduced salivation. GU: Menorrhagia; orgasmic dysfunction; dry vagina; erectile dysfunction. HEMATOLOGIC: Epistaxis; purpura; anemia. HEPATIC: Hepatic failure; hepatitis. METABOLIC: Increased AST and ALT. RESPIRATORY: Coughing; upper respiratory tract infection; shortness of breath. OTHER: Arthralgia; back pain; chest pain; fever; polyuria or polydipsia; increased weight; elevated prolactin levels.

 Precautions

Pregnancy: Category C. Lactation: Undetermined; do not breastfeed. Children: Safety and efficacy not established. Elderly and debilitated patients: May have reduced ability to eliminate risperidone. At increased risk of tardive dyskinesia, especially elderly women. Cardiac effects: Appears to have proarrhythmic effects. Orthostatic hypotension may also occur. Change in drug therapy: When patient is switched from another antipsychotic to risperidone, it is recommended that the other antipsychotic be discontinued before starting risperidone therapy or to minimize period of overlap. Hepatic/Renal function impairment: Patients with hepatic/renal impairment may experience enhanced effect of risperidone because of reduced ability to eliminate risperidone. Dose adjustment may be required. Long-term use (more than 8 wk): Long-term use not well evaluated. Periodically re-evaluate usefulness. Neuroleptic malignant syndrome: Neuroleptic malignant syndrome has occurred with antipsychotics; is potentially fatal. Signs and symptoms are hyperpyrexia, muscle rigidity, altered mental status, irregular pulse, irregular BP, tachycardia, and diaphoresis. Tardive dyskinesia: A potentially irreversible syndrome of involuntary body and facial movements may occur.

 Administration/Storage

• May be given without regard to meals.
• Administer tablet with full glass of water.
• Mix oral solution dose with 3 to 4 oz water, coffee, orange juice, or low-fat milk. Not compatible with cola or tea.
• Dosage will be adjusted daily for first 3 days and then at weekly intervals as indicated.
• Store at room temperature, protected from light and moisture.

 Assessment/Interventions

• Obtain patient history, including drug history and any known allergies.
• Obtain baseline renal and LFT results.
• Obtain baseline BP and monitor postural BP at regular intervals, especially after dosages changes.
• Inform health care provider immediately if hyperpyrexia, muscle rigidity, altered mental status, irregular pulse and BP, tachycardia, and diaphoresis develop.
• Assess baseline neurologic status and observe during treatment for involuntary body and facial movements, drowsiness, headache, insomnia, agitation, anxiety, aggressive reaction, dizziness, or seizure activity.
• Monitor cardiac patients during initiation of drug for prolongation of QT interval; notify health care provider if this occurs.
• Notify health care provider if any of the following develops: tachycardia, chest pain, arrhythmias, hypertension, nausea, vomiting, abdominal pain, upper respiratory tract infection, cough, shortness of breath, epistaxis, purpura, rash, visual disturbances, arthralgias, or fever.
• Monitor patient for suicidal tendencies often associated with schizophrenia. Assess medication compliance.

 Patient/Family Education

• Tell patient to immediately report hyperpyrexia, muscle rigidity, altered mental status, irregular pulse, tachycardia, and diaphoresis to health care provider.
• Instruct patient to drink adequate liquids while taking drug.
• Advise patient that drug may cause photosensitivity and to use sunscreen or wear protective clothing until tolerance to the sun/UV light is determined.
• Instruct patient to avoid alcoholic beverages.
• Instruct patient to get up slowly from lying or sitting position and to avoid sudden position changes to prevent postural hypotension. Advise patient to report dizziness with position changes to health care provider. Caution patient to avoid hot tubs, hot showers, and baths.
• Advise patient taking antihypertensives to monitor BP at regular intervals.
• Instruct patient to notify health care provider of the following: drowsiness, insomnia, increased agitation or anxiety, seizures, excessive fatigue, involuntary body and facial movements, constipation, nausea, vomiting, polyuria, excessive thirst, cough, shortness of breath, upper respiratory infection, angina, palpitations, fever, rash, visual disturbances, sexual problems, vaginal dryness, menorrhagia, epistaxis, purpura, abdominal pain, change in color or consistency of stools, arthralgias.
• Instruct patient to take sips of water frequently or to suck on ice chips, sugarless hard candy, or chewing gum if dry mouth occurs.
• Advise patient that drug may cause drowsiness and to use caution while driving or performing other tasks requiring mental alertness.
• Advise patient about potential weight gain.

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Copyright © 2003 Facts and Comparisons
David S. Tatro
A to Z Drug Facts