Nurses Compass
Drug Guide
Asenapine
Classification
Therapeutic: Antipsychotic
Pharmacological: Atypical (second-generation) antipsychotic
FDA Approved Indications
- Schizophrenia
- Bipolar I disorder (manic or mixed episodes, as monotherapy or adjunctive therapy)
Mechanism of Action
Asenapine exerts its antipsychotic effects primarily by antagonizing dopamine D2 and serotonin 5-HT2A receptors, along with activity at other serotonergic, adrenergic, and histaminergic receptors, contributing to its efficacy and side effect profile.
Dosage and Administration
Adult: Initially, 10 mg twice daily; dose may be titrated based on response and tolerability, up to 20 mg twice daily.
Pediatric: Not approved for pediatric use; safety and efficacy not established.
Geriatric: Use with caution; starting dose typically lower and titrate carefully due to increased sensitivity.
Renal Impairment: No specific dosage adjustment recommended; monitor closely.
Hepatic Impairment: Use with caution; consider starting at lower doses due to possible decreased metabolism.
Pharmacokinetics
Absorption: Rapidly absorbed orally, with peak plasma concentrations in approximately 0.5–1 hour.
Distribution: Widely distributed; plasma protein binding approximately 89%.
Metabolism: Extensively metabolized in the liver primarily via CYP1A2, with minor contributions from CYP2D6 and CYP3A4.
Excretion: Metabolites excreted mainly in urine and feces.
Half Life: Approximately 24 hours.
Contraindications
- Hypersensitivity to asenapine or excipients
Precautions
- History of QT prolongation or cardiovascular disease
- Seizure disorder
- Orthostatic hypotension
- Elderly patients with dementia-related psychosis (risk of death)
- Use with caution in hepatic impairment
Adverse Reactions - Common
- Akathisia (Common)
- Sedation (Common)
- Somnolence (Common)
- Dizziness (Common)
- Weight gain (Common)
Adverse Reactions - Serious
- QT prolongation (Serious)
- Neuroleptic malignant syndrome (Serious)
- Hyperglycemia/Diabetes Mellitus (Serious)
- Orthostatic hypotension (Serious)
- Seizures (Serious)
Drug-Drug Interactions
- CYP1A2 inhibitors (e.g., fluvoxamine) can increase asenapine levels
- CYP1A2 inducers (e.g., smoking) can decrease levels
- Other QT prolonging agents
Drug-Food Interactions
- Caffeine may reduce plasma concentrations
Drug-Herb Interactions
- St. John's Wort may decrease plasma levels
Nursing Implications
Assessment: Monitor mental status, mood, behavior changes, and side effects such as EPS, metabolic parameters, and cardiovascular status including ECG in at-risk patients.
Diagnoses:
- Risk for falls
- Risk for metabolic syndrome
- Monitoring medication effectiveness
Implementation: Administer as prescribed; educate patients on adherence and side effect reporting.
Evaluation: Assess symptom improvement, side effects, metabolic parameters periodically.
Patient/Family Teaching
- Take medication exactly as prescribed; do not alter dose without consulting healthcare provider.
- Be aware of side effects such as drowsiness, dizziness, and movement disorders.
- Report signs of metabolic changes like significant weight gain, increased thirst, or urination.
- Caution about orthostatic hypotension and risk of falls.
- Limit alcohol intake and avoid other CNS depressants unless approved.
Special Considerations
Black Box Warnings:
- Elderly patients with dementia-related psychosis treated with antipsychotics are at increased risk of death.
Genetic Factors: CYP1A2 polymorphisms may influence plasma levels.
Lab Test Interference: No significant interference reported.
Overdose Management
Signs/Symptoms: Drowsiness, agitation, extrapyramidal symptoms, tachycardia, hypotension, QT prolongation.
Treatment: Supportive care, ECG monitoring, activated charcoal if early, and appropriate symptomatic treatment.
Storage and Handling
Storage: Store at room temperature, 20°C to 25°C (68°F to 77°F).
Stability: Stable until expiration date when stored properly.