Nurses Compass
Drug Guide
Amoxapine
Classification
Therapeutic: Antidepressant, Antipsychotic
Pharmacological: Tricyclic antidepressant, Dopamine receptor antagonist
FDA Approved Indications
- Major depressive disorder
Mechanism of Action
Amoxapine works by modulating neurotransmitters in the brain, primarily inhibiting the reuptake of norepinephrine and serotonin, and antagonizing dopamine D2 receptors, which contributes to its antidepressant and antipsychotic effects.
Dosage and Administration
Adult: Typically 100-200 mg per day in divided doses, titrated based on response and tolerability.
Pediatric: Not generally recommended for children and adolescents due to limited data.
Geriatric: Start at the lower end of dosing; monitor closely for side effects.
Renal Impairment: Adjust dosage cautiously; close monitoring recommended.
Hepatic Impairment: Use with caution; consider dosage reduction.
Pharmacokinetics
Absorption: Well absorbed from the gastrointestinal tract.
Distribution: Widely distributed; crosses the blood-brain barrier.
Metabolism: Metabolized in the liver via hydroxylation and demethylation.
Excretion: Primarily excreted in urine as metabolites.
Half Life: Approximately 8-15 hours, but varies depending on individual metabolism.
Contraindications
- History of hypersensitivity to amoxapine or other tricyclic antidepressants.
- Recent myocardial infarction.
Precautions
- Use cautiously in patients with seizure disorders, urinary retention, glaucoma, or hepatic impairment.
- Potential for suicidal thoughts; monitor appropriately.
- Pregnancy Category C: risk should be weighed against benefits.
Adverse Reactions - Common
- Drowsiness (Common)
- Dry mouth (Common)
- Dizziness (Common)
- Weight gain (Common)
Adverse Reactions - Serious
- Arrhythmias (Serious)
- Seizures (Serious)
- Neuroleptic malignant syndrome (Serious)
- Hepatotoxicity (Serious)
Drug-Drug Interactions
- MAO inhibitors: risk of hypertensive crisis and serotonin syndrome.
- Other serotonergic drugs: increased risk of serotonin syndrome.
- CNS depressants: enhance sedative effects.
Drug-Food Interactions
- Alcohol: intensifies CNS depression.
Drug-Herb Interactions
N/ANursing Implications
Assessment: Assess mental status, suicidal ideation, and drug side effects.
Diagnoses:
- Risk for injury related to dizziness or hypotension.
- Impaired physical mobility due to sedation.
Implementation: Administer with food to minimize gastrointestinal side effects. Monitor blood pressure and mental status.
Evaluation: Monitor for therapeutic effects and adverse reactions, including mood improvement and side effects.
Patient/Family Teaching
- Take medication exactly as prescribed.
- Do not stop medication abruptly.
- Avoid alcohol and CNS depressants.
- Report side effects such as worsening depression, suicidal thoughts, or signs of allergic reactions.
Special Considerations
Black Box Warnings:
- Increased risk of suicidal thoughts and behaviors in children, adolescents, and young adults.
Genetic Factors: Genetic variations in CYP2D6 and CYP1A2 can affect metabolism.
Lab Test Interference: None known.
Overdose Management
Signs/Symptoms: Drowsiness, tachycardia, hypotension, seizures, coma.
Treatment: Supportive care, gastric lavage, activated charcoal, and management of cardiac arrhythmias. In severe cases, administer physostigmine for anticholinergic toxicity.
Storage and Handling
Storage: Store at room temperature, away from light and moisture.
Stability: Stable under normal conditions for prescribed shelf life.