## Most Common PONV Antiemetic in Clinical Practice **Key Point:** Ondansetron is the most frequently prescribed antiemetic for post-operative nausea and vomiting in both Indian and global surgical practice due to its excellent efficacy, rapid onset, and favorable side-effect profile. ### Why Ondansetron Dominates PONV Management 1. **Rapid onset:** 30 minutes (IV) or 1–2 hours (oral) 2. **High efficacy:** ~70–80% prevention of PONV when given prophylactically 3. **Minimal side effects:** No extrapyramidal effects, no sedation 4. **Cost-effectiveness:** Generic formulations widely available in India 5. **Versatility:** Effective for both nausea and vomiting, multiple routes of administration ### Comparative Profile of PONV Antiemetics | Agent | Class | Onset (min) | Efficacy | Common Use | Limitations | |---|---|---|---|---|---| | **Ondansetron** | 5-HT₃ antagonist | 30–60 | Excellent (70–80%) | **First-line** | Cost (though generic) | | Metoclopramide | D₂ antagonist | 10–20 | Moderate (40–50%) | Adjunct | Tardive dyskinesia risk, limited efficacy | | Dexamethasone | Corticosteroid | 60–120 | Good (60–70%) | Adjunct (not monotherapy) | Delayed onset, hyperglycemia | | Aprepitant | NK₁ antagonist | 120+ | Excellent | Research/adjunct | Expensive, slow onset, drug interactions | **High-Yield:** Ondansetron 4–8 mg IV given at induction of anesthesia or at the end of surgery is the most common prophylactic regimen in Indian operating theaters. It is often combined with dexamethasone for enhanced effect. **Clinical Pearl:** Metoclopramide, though cheaper and faster-acting, has fallen out of favor as monotherapy due to modest efficacy (~40–50%) and risk of tardive dyskinesia with repeated use. It is now reserved as an adjunct. **Mnemonic:** **ONDANSETRON = ON-DEMAND-SET-NAUSEA-RESOLUTION** (the most readily available, go-to antiemetic for PONV).
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