5-hydroxytryptamine 3 receptor antagonist

A class of drugs that block the action of serotonin at the 5-HT3 receptor

5-Hydroxytryptamine 3 receptor antagonists (5-HT3 receptor antagonists) are a class of medications that are primarily used to treat nausea and vomiting, particularly those associated with chemotherapy, radiation therapy, and surgery. These drugs work by blocking the action of serotonin at the 5-HT3 receptor, which is a type of serotonin receptor found in the central and peripheral nervous systems.

Mechanism of Action

5-HT3 receptor antagonists exert their effects by selectively blocking the 5-HT3 receptors. These receptors are ligand-gated ion channels that, when activated by serotonin, allow the flow of ions such as sodium and potassium across the cell membrane. This ion flow leads to depolarization and the transmission of signals that can trigger nausea and vomiting reflexes. By inhibiting these receptors, 5-HT3 antagonists prevent the initiation of these reflexes.

Clinical Uses

5-HT3 receptor antagonists are primarily used in the management of:

• Chemotherapy-induced nausea and vomiting (CINV): These drugs are effective in preventing both acute and delayed phases of CINV.
• Postoperative nausea and vomiting (PONV): They are used to prevent nausea and vomiting following surgical procedures.
• Radiation-induced nausea and vomiting: They help manage nausea and vomiting associated with radiation therapy.

Common 5-HT3 Receptor Antagonists

Some of the commonly used 5-HT3 receptor antagonists include:

• Ondansetron: One of the first and most widely used 5-HT3 antagonists.
• Granisetron: Similar to ondansetron, used for CINV and PONV.
• Dolasetron: Used for the prevention of nausea and vomiting.
• Palonosetron: Notable for its long half-life and efficacy in delayed CINV.

Side Effects

While 5-HT3 receptor antagonists are generally well-tolerated, they can cause some side effects, including:

• Headache
• Constipation
• Dizziness
• QT interval prolongation, which can lead to cardiac arrhythmias in susceptible individuals.

Pharmacokinetics

The pharmacokinetic properties of 5-HT3 receptor antagonists can vary, but they are generally well-absorbed orally and have a moderate to long half-life. For example, palonosetron has a half-life of approximately 40 hours, allowing for less frequent dosing.

Also see

• Serotonin receptor
• Nausea and vomiting
• Chemotherapy-induced nausea and vomiting
• Postoperative nausea and vomiting