Nurses Compass
Drug Guide
Aprepitant
Classification
Therapeutic: Antiemetic
Pharmacological: Neurokinin-1 (NK1) receptor antagonist
FDA Approved Indications
- Prevention of chemotherapy-induced nausea and vomiting (CINV) including prophylaxis of acute and delayed nausea and vomiting
Mechanism of Action
Aprepitant blocks substance P/neurokinin-1 (NK1) receptors in the brain's vomiting center and in the gastrointestinal tract, preventing nausea and vomiting signals.
Dosage and Administration
Adult: 125 mg on day 1, then 80 mg once daily on days 2 and 3 for CINV prevention.
Pediatric: Dosing varies; consult specific guidelines based on age and weight.
Geriatric: No specific dosage adjustment necessary but monitor for increased sensitivity.
Renal Impairment: No dose adjustment necessary.
Hepatic Impairment: Reduce dose in moderate to severe hepatic impairment.
Pharmacokinetics
Absorption: Well absorbed orally.
Distribution: Widely distributed; high protein binding.
Metabolism: Primarily hepatic via CYP3A4 and CYP1A2.
Excretion: Metabolites excreted in urine and feces.
Half Life: Approximately 9-13 hours.
Contraindications
- Hypersensitivity to aprepitant or any component of the formulation.
Precautions
- Use cautiously with medications that are substrates, inhibitors, or inducers of CYP3A4 or CYP2C9.
- Monitor for interactions, especially with warfarin and hormonal contraceptives.
Adverse Reactions - Common
- Fatigue (Common)
- Nausea (Common)
- Hiccups (Less common)
Adverse Reactions - Serious
- Serious skin reactions, including Stevens-Johnson syndrome (Rare)
- Anaphylaxis (Rare)
Drug-Drug Interactions
- CYP3A4 inhibitors (e.g., ketoconazole, erythromycin) increase aprepitant levels.
- CYP3A4 inducers (e.g., rifampin) decrease efficacy.
- Warfarin: monitor INR closely.
- Hormonal contraceptives: reduce effectiveness.
Drug-Food Interactions
N/ADrug-Herb Interactions
N/ANursing Implications
Assessment: Assess for allergies, current medications, and potential drug interactions.
Diagnoses:
- Risk for decreased drug efficacy or toxicity due to drug interactions.
Implementation: Administer as prescribed, preferably with a full glass of water.
Evaluation: Monitor effectiveness in preventing nausea and vomiting, and for adverse effects.
Patient/Family Teaching
- Take medication exactly as prescribed.
- Report any severe or unusual side effects.
- Use additional contraceptive measures if hormonal contraceptives are affected.
- Inform healthcare provider about all medications being taken.
Special Considerations
Black Box Warnings:
- None currently,
Genetic Factors: Consider CYP3A4 genetic polymorphisms that may affect metabolism.
Lab Test Interference: May increase bleeding time tests; monitor accordingly.
Overdose Management
Signs/Symptoms: Nausea, vomiting, drowsiness.
Treatment: Supportive care, activated charcoal if ingestion was recent, and symptomatic treatment.
Storage and Handling
Storage: Store at room temperature, away from moisture and heat.
Stability: Stable as per manufacturer's instructions.