5-HT3 receptor antagonist

5-HT3 Receptor Antagonist

A 5-HT3 receptor antagonist is a type of medication that inhibits the action of serotonin at the 5-HT3 receptor, a subtype of serotonin receptor found in the central and peripheral nervous systems. These antagonists are primarily used to prevent and treat nausea and vomiting, particularly those induced by chemotherapy, radiation therapy, and surgery.

Mechanism of Action

5-HT3 receptor antagonists work by blocking the 5-HT3 receptors located in the chemoreceptor trigger zone (CTZ) and the gastrointestinal tract. Serotonin, a neurotransmitter, can bind to these receptors and trigger nausea and vomiting reflexes. By inhibiting this binding, 5-HT3 receptor antagonists prevent the emetic signals from being transmitted to the brain.

Clinical Uses

5-HT3 receptor antagonists are primarily used in the following clinical scenarios:

• Chemotherapy-Induced Nausea and Vomiting (CINV): These drugs are highly 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 (RINV): 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 - Known for its long half-life and efficacy.
• Dolasetron - Used in both oral and intravenous forms.
• Palonosetron - Notable for its long duration of action and effectiveness 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 - A rare but serious cardiac effect that requires monitoring.

Pharmacokinetics

The pharmacokinetic properties of 5-HT3 receptor antagonists vary among different agents. For example, palonosetron has a longer half-life compared to ondansetron, which influences dosing schedules and duration of action.

Research and Development

Ongoing research is focused on improving the efficacy and safety profile of 5-HT3 receptor antagonists, as well as exploring their potential use in other conditions such as irritable bowel syndrome (IBS).

Also see

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