Antiemetikum

Antiemetikum, or antiemetic, is a medication that prevents or relieves nausea and vomiting. They are used to prevent postoperative nausea and vomiting (PONV), chemotherapy-induced nausea and vomiting (CINV), motion sickness, and nausea from gastroenteritis or pregnancy. Antiemetics work by blocking or modulating signals in the gut and brain that trigger the vomiting reflex, including receptors in the chemoreceptor trigger zone and the vomiting center.

Major drug classes include:

- Serotonin 5-HT3 receptor antagonists (ondansetron, granisetron, palonosetron) which are effective for CINV and PONV; potential QT interval effects.

- Dopamine receptor antagonists (metoclopramide, prochlorperazine) with antiemetic and prokinetic properties; may cause extrapyramidal symptoms.

- Antihistamines (dimenhydrinate, meclizine) and anticholinergics (scopolamine) used for motion sickness and mild nausea; often sedating.

- Neurokinin-1 receptor antagonists (aprepitant, fosaprepitant) used with other agents for CINV.

- Corticosteroids (dexamethasone) as adjuncts in CINV.

- Benzodiazepines (lorazepam) for anxiety and anticipatory nausea.

- Cannabinoids (dronabinol) in some regimens.

Common considerations include routes of administration (oral, intravenous, intramuscular, transdermal) and combination regimens for high-risk patients. Side effects vary by agent and may include sedation, dry mouth, constipation, extrapyramidal symptoms from dopamine antagonists, and QT prolongation with some 5-HT3 antagonists. Cautions include liver disease, pregnancy considerations, and potential drug interactions.

Guidelines from professional societies emphasize tailoring antiemetic therapy to the underlying risk and treatment plan, balancing efficacy with safety.