**Question:** Antiemetic used in vomiting induced by anticancer drugs is:

**Core Concept:**
Antiemetics are medications that help prevent or relieve nausea and vomiting. Chemotherapy-induced vomiting is a common side effect of anticancer drugs.

**Why the Correct Answer is Right:**
The correct answer is Dolasetron (Anzemet). Dolasetron is a selective serotonin receptor antagonist, specifically targeting serotonin receptors (5-HT3 receptors) that are involved in the pathophysiology of chemotherapy-induced vomiting. By blocking these receptors, Dolasetron helps prevent emesis (nausea and vomiting).

**Why Each Wrong Option is Incorrect:**
A. Ondansetron (Zofran) is also a selective serotonin receptor antagonist, but it targets both 5-HT3 and histamine receptors (H1 receptors). While effective in treating nausea and vomiting, it is not as specific as Dolasetron for the treatment of chemotherapy-induced vomiting.

B. Granisetron (Sustol) is another selective serotonin receptor antagonist, targeting 5-HT3 receptors. However, it is not as potent as Dolasetron and has a slightly broader spectrum of action, making it less effective in preventing chemotherapy-induced vomiting.

C. Rizatriptan (Maxalt) is a selective serotonin receptor agonist, specifically activating serotonin receptors (5-HT1B/1D receptors) involved in migraine treatment. It has no role in preventing chemotherapy-induced vomiting as it targets a different receptor system.

**Clinical Pearl:**
The optimal choice for preventing chemotherapy-induced emesis is a combination of a 5-HT3 receptor antagonist (such as Dolasetron) and a neurokinin-1 receptor antagonist (such as aprepitant). This combination therapy provides superior efficacy and minimizes the risk of adverse effects compared to using a single agent.

**Correct Answer:** Dolasetron (Anzemet) is the correct answer as it is a highly selective 5-HT3 receptor antagonist, targeting the specific receptors involved in chemotherapy-induced vomiting. Other options are not as potent in blocking 5-HT3 receptors and are not as effective in treating chemotherapy-induced vomiting.