Products
Aprepitant is commercially available in the form of capsules (Emend). It has been approved in many countries since 2003.
Structure and properties
Aprepitant (C23H21F7N4O3, Mr = 534.4 g/mol) is a morpholine and triazol-3-one derivative. It exists as a white crystalline powder that is practically insoluble in water. For intravenous use, the more water-soluble prodrug fosaprepitant (Ivemend), a -phosphoryl derivative of aprepitant, is also used.
Effects
Aprepitant (ATC A04AD12) has antiemetic properties. The effects are due to selective antagonism at neurokinin-1 (NK1) receptors. Aprepitant competitively blocks the effects of the natural ligand substance P, the most abundant neurokinin in the central nervous system.
Indications
In combination with a 5-HT3 antagonist and dexamethasone to prevent nausea and vomiting associated with chemotherapy.
Contraindications
- Hypersensitivity
- Combination with pimozide, terfenadine, astemizole, or cisapride (all of these drugs are off-label in many countries)
Full details of precautions and interactions can be found in the drug label.
Interactions
Numerous drug-drug interactions are possible. Aprepitant is an inhibitor, a substrate, and an inducer of CYP3A4 and induces CYP2C9. CYP3A4 inhibition may increase the concentration of substrates and cause adverse effects and toxicity.
Adverse effects
The most common potential adverse effects include digestive upset, fatigue, hiccups, poor appetite, and elevated liver enzymes (ALT).
