Aprepitant is a neurokinin-1 (NK1) receptor antagonist, primarily used to prevent acute and delayed nausea and vomiting caused by chemotherapy.

Precautions for Aprepitant Administration

Medication in Special Populations

Patients with renal impairment: No dosage adjustment is required, including those with end-stage renal disease who need hemodialysis.

Elderly patients: Exposure to the drug may increase in patients over 65 years of age, but dosage adjustment is generally not needed. However, concurrent diseases and other medications being taken should be considered.

Pregnant women: Animal studies have not shown embryonic toxicity, but human data are limited. The benefits and risks should be weighed when using the drug, and effective contraceptive measures must be taken during treatment and for 1 month after discontinuing the drug.

Drug Interactions

Contraindicated concurrent drugs: Pimozide (may cause QT interval prolongation).

Drugs requiring dosage adjustment:

Dexamethasone: The dose should be reduced by 50% when used in combination.

Methylprednisolone: Reduce the dose by 25% for intravenous administration and by 50% for oral administration.

Warfarin: The International Normalized Ratio (INR) should be monitored 7–10 days after treatment initiation (INR may decrease).

Hormonal contraceptives: Their effectiveness may be reduced; alternative contraceptive methods should be used during treatment and for 1 month after discontinuing the drug.

Strong CYP3A4 inhibitors: Drugs such as ketoconazole may increase the plasma concentration of aprepitant; concurrent use should be avoided.

Strong CYP3A4 inducers: Drugs such as rifampicin may reduce the efficacy of aprepitant; concurrent use should be avoided.

Medication Monitoring for Aprepitant

Pre-Treatment Assessment

Conduct a detailed review of the patient’s medication history, with special attention to drugs that are CYP3A4 substrates.

Perform liver function tests (especially for patients with severe liver disease).

Conduct pregnancy testing for women of childbearing age (to confirm non-pregnancy).

Measure the baseline INR value for patients using warfarin.

Evaluate the history of nausea and vomiting caused by previous chemotherapy.

Efficacy Monitoring

Record the number of vomiting episodes within 0–24 hours (acute phase) and 25–120 hours (delayed phase) after chemotherapy.

Assess the severity of nausea (use of Visual Analog Scale [VAS] is recommended).

Document the use of rescue antiemetic drugs.

Safety Monitoring

Liver function: Especially for patients using the drug long-term or for multiple cycles.

Warfarin effect: Focus on monitoring INR 7–10 days after the start of treatment.

Central nervous system: Monitor for neurotoxic symptoms when used in combination with ifosfamide.

Allergic reactions: Observe for hypersensitivity manifestations such as rash and pruritus.