📌 Introduction
Antiemetic drugs are used to prevent and treat nausea and vomiting. These symptoms can occur due to various conditions such as motion sickness, chemotherapy, pregnancy, and gastrointestinal disorders.
This topic is very important for GPAT, DSSSB, and other pharmacy exams.
🔍What are Antiemetic Drugs?
Antiemetics are drugs that act on the vomiting center in the brain or gastrointestinal tract to prevent nausea and vomiting.
📝 Classification of Antiemetic Drugs
1. Serotonin (5-HT3) Receptor Antagonists
• Ondansetron
• Granisetron
2. Dopamine (D2) Receptor Antagonists
• Metoclopramide
• Domperidone
3. Antihistamines (H1 blockers)
• Promethazine
• Meclizine
4. Anticholinergics
• Scopolamine
5. Neurokinin-1 (NK1) Receptor Antagonists
• Aprepitant
🧬 Mechanism of Action
• 5-HT3 antagonists → block serotonin receptors in GI tract & brain
• D2 antagonists → block dopamine receptors
• H1 blockers → reduce vestibular stimulation
• Anticholinergics → block muscarinic receptors
• NK1 antagonists → block substance P
👉 Result: Prevention of vomiting reflex
🩺 Pharmacological Effects
• Prevention of nausea
• Suppression of vomiting
• Improved patient comfort
💊 Therapeutic Uses
• Motion sickness
• Chemotherapy-induced vomiting
• Postoperative nausea
• Pregnancy-related nausea
🚨 Side Effects
• Drowsiness
• Dry mouth
• Constipation
• Headache
📑 Important Exam Points
• Ondansetron → 5-HT3 antagonist
• Metoclopramide → D2 blocker
• Scopolamine → motion sickness
• Aprepitant → chemotherapy vomiting
🛑 Precautions
• Avoid overuse
• Monitor side effects
• Use appropriate drug for specific cause
• Caution in pregnancy
🎯 Conclusion
Antiemetic drugs play a crucial role in managing nausea and vomiting. Understanding their classification, mechanism, and uses is essential for pharmacology exams and clinical practice.
👉 Practice MCQs in evening post
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