Drug Guide
Aripiprazole
Classification
Therapeutic: Antipsychotic
Pharmacological: Partial dopamine agonist, dopamine D2/D3 receptor antagonist
FDA Approved Indications
- Schizophrenia in adults and adolescents
- Bipolar I disorder in adults and pediatric patients aged 10 and older
- Major depressive disorder (adjunctive)
- Irritability associated with autism spectrum disorder in children aged 6 and older
- Tourettes disorder (short-term use)
Mechanism of Action
Aripiprazole acts as a partial agonist at dopamine D2 and serotonin 5-HT1A receptors and as an antagonist at serotonin 5-HT2A receptors. This modulation stabilizes neurotransmitter activity related to psychosis and mood disorders.
Dosage and Administration
Adult: Dosage varies by condition. For schizophrenia, typically starting at 10-15 mg once daily, titrated as needed. For bipolar disorder, usual starting dose is 15 mg daily.
Pediatric: Schizophrenia: 10-30 mg once daily; Bipolar disorder: 10-30 mg once daily, based on the specific indication and age.
Geriatric: Usually starting at the lower end of the dosing range, with careful monitoring.
Renal Impairment: Use with caution; dose adjustments may be necessary.
Hepatic Impairment: Start at lower doses; monitor closely.
Pharmacokinetics
Absorption: Well absorbed orally, with peak plasma concentrations within 3-5 hours.
Distribution: Highly protein bound (~99%), volume of distribution approximately 12 L/kg.
Metabolism: Extensively metabolized in the liver via CYP2D6 and CYP3A4 enzymes.
Excretion: Primarily excreted in feces (about 60%) and urine (about 25%).
Half Life: Approximately 75 hours (range 47-136 hours).
Contraindications
- None specific, but use cautiously in patients with hypersensitivity.
Precautions
- Use with caution in elderly patients with dementia-related psychosis due to increased risk of mortality.
- Monitor for metabolic side effects, including weight gain, hyperglycemia, and dyslipidemia.
- Assess for suicidality, especially in pediatric and young adult patients.
Adverse Reactions - Common
- Akathisia (frequent)
- Weight gain (common)
- Insomnia (common)
- Nausea (common)
Adverse Reactions - Serious
- Extrapyramidal symptoms (uncommon)
- Neuroleptic malignant syndrome (rare)
- QT prolongation (rare)
- Seizures (rare)
Drug-Drug Interactions
- CYP3A4 inhibitors or inducers (e.g., ketoconazole, rifampin) may alter aripiprazole levels.
- Other CNS depressants may enhance sedative effects.
Drug-Food Interactions
- Avoid grapefruit juice as it may increase plasma concentrations.
Drug-Herb Interactions
- St. John’s Wort may reduce aripiprazole levels.
Nursing Implications
Assessment: Monitor mental status, mood, and behavior; check baseline weight, glucose, lipids. Watch for signs of movement disorders and metabolic changes.
Diagnoses:
- Risk for weight gain related to medication side effects.
- Risk for extrapyramidal symptoms.
Implementation: Administer with or without food. Educate about potential side effects, importance of adherence, and regular lab monitoring.
Evaluation: Assess effectiveness in managing symptoms; monitor for adverse reactions; evaluate metabolic parameters periodically.
Patient/Family Teaching
- Take medication exactly as prescribed.
- Report any concerning side effects such as movement changes or severe sedation.
- Maintain regular follow-up appointments for monitoring.
- Inform about potential metabolic side effects and lifestyle modifications needed.
Special Considerations
Black Box Warnings:
- Increased mortality in elderly patients with dementia-related psychosis.
- Suicidality risk in children, adolescents, and young adults.
Genetic Factors: CYP2D6 poor metabolizers may have higher plasma levels; consider dose adjustment.
Lab Test Interference: May affect blood glucose and lipid tests.
Overdose Management
Signs/Symptoms: Drowsiness, dizziness, agitation, tachycardia, vomiting, hallucinations, seizures.
Treatment: Supportive care, activated charcoal if ingestion is recent, and symptomatic treatment. No specific antidote.
Storage and Handling
Storage: Store at room temperature, 20-25°C (68-77°F). Keep container tightly closed.
Stability: Stable under recommended storage conditions for the duration of the labeled shelf life.