RISPERIDONE

RISPERIDONE
(ris-per'i-done)
Risperdal, Risperdal M-TAB, Risperdal Consta
Classifications: psychotherapeutic, antipsychotic, atypical;
Therapeutic: antipsychotic, atypical

Prototype: Clozapine
Pregnancy Category: C

Availability

0.25 mg, 0.5 mg, 1 mg, 2 mg, 3 mg, 4 mg tablets; 0.5 mg, 1 mg, 2 mg, 3 mg, 4 mg quick-dissolving tablets; 1 mg/mL solution; 12.5 mg, 25 mg, 37.5 mg, 50 mg injection

Action

Interferes with binding of dopamine to D2-interlimbic region of the brain, serotonin (5-HT2) receptors, and alpha-adrenergic receptors in the occipital cortex. It has low to moderate affinity for the other serotonin (5-HT) receptors.

Therapeutic Effect

Effective in controlling symptoms of schizophrenia as well as other psychotic symptoms.

Uses

Treatment of schizophrenia; treatment of bipolar disorder; irritability associated with autism.

Unlabeled Uses

Management of patients with dementia-related psychotic symptoms. Adjunctive treatment of behavioral disturbances in patients with mental retardation.

Contraindications

Hypersensitivity to risperidone; elderly with dementia-related psychosis; QT prolongation, Reye's syndrome, brain tumor, severe CNS depression, head trauma; suicidal ideation, tardive dyskinesia; sunlight (UV) exposure, tanning beds; pregnancy (category C), lactation, children <15 y.

Cautious Use

Older adults; arrhythmias, hypotension, breast cancer, blood dyscrasia, cardiac disorders, cerebrovascular disease, hypotension, dehydration, diabetes mellitus, diabetic ketoacidosis, hyperglycemia, hypokalemia, hypomagnesemia, hyponatremia, MI, obesity, orthostatic hypotension, mild or moderate CNS depression, coma; GI obstruction, dysphagia; electrolyte imbalance, ethanol intoxication, heart failure, renal or hepatic dysfunction; seizure disorder, seizures, stroke, Parkinson's disease.

Route & Dosage

Schizophrenia
Adult/Adolescent (>13 y): PO 1–2 mg/d in 1 or 2 doses, then titrate up (max: 8 mg/d) IM 25 mg once q2wk (max: 50 mg)
Geriatric: PO Start 0.5 mg b.i.d. and increase by 0.5 mg b.i.d. daily to an initial target of 1.5 mg b.i.d. (max: 4 mg/d) IM 25 mg once q2wk (max: 25 mg)

Bipolar Disorder
Adult/Adolescent (>10 y): PO 2–3 mg once daily for up to 3 wk (max: 6 mg/d)
Geriatric: PO Start with 0.5 mg b.i.d. and increase by 0.5 mg b.i.d. daily to an initial target of 1.5 mg b.i.d. (max: 4 mg/d). May convert to once daily dosing after stabilized in b.i.d. 2–3 d.

Irritability Associated with Autism
Adolescent/Child (≥5 y, ≥20 kg): PO 0.5 mg q.d.; after 4 d, increase to 1 mg q.d.; can increase by 0.5 mg q2wk
Child (≥5 y, <20 kg): PO 0.25 mg q.d.; after 4 d, increase to 0.5 mg q.d.; can increase by 0.25 mg q2wk

Renal Impairment
Clcr <30 mL/min: start with 0.5 mg b.i.d., increase by 0.5 mg b.i.d. daily to an initial target of 1.5 mg b.i.d., may increase by 0.5 mg b.i.d. at weekly intervals (max: 6 mg/d); lower IM dose may be required

Hepatic Impairment
Start with dose of 0.5 mg b.i.d.

Administration

Oral
  • Note that quick-dissolving tablets dissolve rapidly when placed on tongue.
  • Do not exceed increases/decreases of 1 mg b.i.d. in normal populations or 0.5 mg b.i.d. in older adults or the debilitated during dosage adjustments.
  • Make further increases at 1-wk or longer intervals after the target dose of 3 mg b.i.d. in normal populations and 1.5 mg b.i.d. in older adults or the debilitated are reached.
  • Store at 15°–30° C (59°–86° F).
Intramuscular
  • Reconstitute the 25, 37.5, or 50 mg vial using the supplied 2 mL prefilled syringe. Shake vigorously for at least 10 sec to produce a uniform, thick, milky suspension. If 2 min or more pass before injection, shake vial again.
  • Give deep IM into the upper-outer quadrant of the gluteal muscle with the supplied needle; do not substitute. Follow the manufacturer's instructions for use of the SmartSite Needle-Free Vial Access Device and Needle-Pro device.
  • Store unopened vials at 2°–8° C (36°–46° F). Protect from light.

Adverse Effects (≥1%)

Body as a Whole: Orthostatic hypotension with initial doses, sweating, weakness, fatigue. CNS: Sedation, drowsiness, headache, transient blurred vision, insomnia, disinhibition, agitation, anxiety, increased dream activity, dizziness, catatonia, extrapyramidal symptoms (akathisia, dystonia, pseudoparkinsonism), especially with doses >10 mg/d, neuroleptic malignant syndrome (rare), increased risk of stroke in elderly. CV: Prolonged QTc interval, tachycardia. GI: Dry mouth, dyspepsia, nausea, vomiting, diarrhea, constipation, abdominal pain, elevated liver function tests (AST, ALT). Endocrine: Galactorrhea. Metabolic: Hyperglycemia, diabetes mellitus. Respiratory: Rhinitis, cough, dyspnea. Skin: Photosensitivity. Urogenital: Urinary retention, menorrhagia, decreased sexual desire, erectile dysfunction, sexual dysfunction male and female.

Diagnostic Test Interference

Liver function tests (AST, ALT) are elevated.

Interactions

Drug: Risperidone may enhance the effects of certain antihypertensive agents. May antagonize the antiparkinson effects of bromocriptine, cabergoline, levodopa, pergolide, pramipexole, ropinirole. Carbamazepine , phenytoin, phenobarbital, rifampin may decrease risperidone levels. Clozapine may increase risperidone levels.

Pharmacokinetics

Absorption: Rapidly; not affected by food. Onset: Therapeutic effect 1–2 wk. Peak: 1–2 h. Distribution: 0.7 L/kg; in animal studies, risperidone has been found in breast milk. Metabolism: Primarily in liver by cytochrome P450 with an active metabolite, 9-hydroxyrisperidone. Elimination: 70% in urine; 14% in feces. Half-Life: 20 h for slow metabolizers, 30 h for fast metabolizers.

Nursing Implications

Assessment & Drug Effects

  • Monitor diabetics for loss of glycemic control.
  • Reassess patients periodically and maintain on the lowest effective drug dose.
  • Monitor closely neurological status of older adults.
  • Monitor cardiovascular status closely; assess for orthostatic hypotension, especially during initial dosage titration.
  • Monitor closely those at risk for seizures.
  • Assess degree of cognitive and motor impairment, and assess for environmental hazards.
  • Lab tests: Monitor periodically blood glucose, serum electrolytes, liver function, and complete blood counts.

Patient & Family Education

  • Carefully monitor blood glucose levels if diabetic.
  • Do not engage in potentially hazardous activities until the response to drug is known.
  • Be aware of the risk of orthostatic hypotension.
  • Learn adverse effects and report to physician those that are bothersome.
  • Wear sunscreen and protective clothing to avoid photosensitivity.
  • Notify physician if you intend to or become pregnant.

Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; Canadian drug name; Prototype drug

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