Artery of the pterygoid canal

Aprepitant

Chemical structure of Aprepitant

3D ball model of Aprepitant

Aprepitant is a medication used to prevent nausea and vomiting caused by cancer chemotherapy and surgery. It is an antagonist of the neurokinin 1 receptor (NK1 receptor) and works by inhibiting the action of substance P, a neuropeptide involved in the emetic reflex.

Mechanism of Action

Aprepitant works by blocking the NK1 receptor, which is found in the central nervous system. The binding of substance P to this receptor is a key step in the vomiting reflex. By preventing this binding, aprepitant reduces the likelihood of nausea and vomiting.

Clinical Use

Aprepitant is primarily used in combination with other antiemetic agents, such as 5-HT3 receptor antagonists and corticosteroids, to enhance its efficacy. It is particularly effective in preventing delayed nausea and vomiting, which can occur several days after chemotherapy.

Administration

Aprepitant is administered orally, typically as a part of a three-day regimen. The standard dosing involves a higher dose on the first day, followed by lower doses on the subsequent days. It is important to follow the prescribed dosing schedule to achieve optimal results.

Side Effects

Common side effects of aprepitant include fatigue, diarrhea, and hiccups. It may also interact with other medications, particularly those metabolized by the cytochrome P450 enzyme system, necessitating careful monitoring and dose adjustments.

Pharmacokinetics

Aprepitant is well absorbed from the gastrointestinal tract and has a bioavailability of approximately 60-65%. It is extensively metabolized in the liver, primarily by the CYP3A4 enzyme, and has a half-life of about 9-13 hours.

Related Pages

• Neurokinin 1 receptor
• Substance P
• Antiemetic
• Chemotherapy-induced nausea and vomiting