Aprepitant is an antiemetic belonging to the class of substance P/neurokinin 1 (NK1) receptor antagonists, primarily used for preventing chemotherapy-induced nausea and vomiting (CINV).

How to Use Aprepitant

Dosage Regimens

Adults and adolescents aged 12 years and older (capsule formulation):

HEC (Highly Emetogenic Chemotherapy) regimen: 125mg on Day 1, followed by 80mg each on Days 2–3.

MEC (Moderately Emetogenic Chemotherapy) regimen: 125mg on Day 1, followed by 80mg each on Days 2–3.

Children aged 6 months to under 12 years or patients unable to swallow capsules (oral suspension formulation):

Dosed based on body weight: 3mg/kg (maximum 125mg) on Day 1, followed by 2mg/kg (maximum 80mg) each on Days 2–3.

Patients with body weight < 6kg: Use is not recommended.

Administration Timing

Take 1 hour before chemotherapy.

If there is no chemotherapy on Days 2–3, take the medication in the morning.

Dosage Adjustment of Aprepitant

Adjustment Based on Adverse Reactions

Severe skin reactions: Immediate discontinuation is required for conditions such as Stevens-Johnson syndrome.

QT interval prolongation: Discontinue the drug when the corrected QT interval using Fridericia’s formula (QTcF) is ≥ 500ms.

Gastrointestinal reactions: For severe abdominal pain or diarrhea, consider reducing the dose or temporarily suspending administration.

Adjustment for Patients with Hepatic Impairment

Mild to moderate hepatic impairment (Child-Pugh score: 5–9 points): No dosage adjustment is needed.

Severe hepatic impairment (Child-Pugh score > 9 points): Limited data are available; use with caution.

Adjustment Related to Drug Interactions

When used in combination with dexamethasone, the dose of dexamethasone should be reduced by 50%.

When used in combination with methylprednisolone:

The dose of intravenous methylprednisolone should be reduced by 25%.

The dose of oral methylprednisolone should be reduced by 50%.

Administration of Aprepitant in Special Populations

Pregnant Women

The drug can cross the placenta.

Pregnancy status should be confirmed before initiating medication.

Use only when the potential benefit outweighs the potential risk.

Inform the patient of the potential risks to the fetus.

Lactating Women

Whether the drug is excreted into human milk has not been confirmed.

Animal studies (in rats) have shown that the drug can enter breast milk.

Weigh the benefits of breastfeeding against the potential risks of the drug.

If the drug is used, monitor the infant for adverse reactions.

Reproductive-Age Population

The effectiveness of hormonal contraceptives may be reduced.

Non-hormonal contraceptive measures (e.g., condoms) should be used during treatment and for 1 month after discontinuing Aprepitant.

Pediatric Patients

Infants under 6 months: Efficacy has not been established.

Children aged 6 months to 12 years: Oral suspension is the recommended formulation.

Children aged 12 years and older: Capsule formulation can be used.