- Pharmacological Class: Neurokinin-1 (NK1) receptor antagonist.
- Mechanism of Action: Selectively blocks human NK1 receptors in the central nervous system, preventing binding of substance P, a key mediator of chemotherapy-induced nausea and vomiting (CINV) and postoperative nausea and vomiting (PONV).
- Indications in Oncology:
- Prevention of acute and delayed CINV in highly and moderately emetogenic chemotherapy regimens (usually given with a 5-HT3 antagonist and dexamethasone).
- Not effective for treatment once nausea/vomiting has occurred; it is preventive only.
- Formulations:
- Oral capsule, oral suspension, and IV formulation (as fosaprepitant, a prodrug converted to aprepitant).
- Onset & Duration: Oral onset within hours; long half-life (~9–13 h), providing extended coverage of delayed CINV.
- Key Side Effects:
- Fatigue, hiccups, dizziness, constipation, diarrhea, anorexia.
- Rare but possible: hypersensitivity (more with fosaprepitant IV).
- Drug Interactions:
- CYP3A4 substrate, inhibitor, and inducer → can increase plasma concentrations of corticosteroids (dexamethasone, methylprednisolone), and reduce efficacy of hormonal contraceptives.
- Dose adjustments often required when co-administered with dexamethasone.
- Monitoring:
- Efficacy (prevention of nausea/vomiting).
- Potential drug–drug interactions, especially with chemotherapy metabolized by CYP3A4 (e.g., vincristine, etoposide, paclitaxel).
Synonyms
Aprepitant, Fosaprepitant