Among adrenergic agonists used clinically, which is the most commonly prescribed agent for the treatment of hypotension in the perioperative setting across Indian anaesthesia practice?

Explanation

## Most Common Perioperative Vasopressor in India **High-Yield:** Ephedrine is the most frequently used adrenergic agonist for perioperative hypotension in Indian anaesthesia practice due to its unique pharmacokinetic and haemodynamic profile. ### Why Ephedrine Dominates Perioperative Use **Key Point:** Ephedrine is an indirect-acting sympathomimetic (releases endogenous norepinephrine) with dual α and β effects: - **Mechanism:** Releases stored catecholamines from nerve terminals + direct receptor stimulation - **Haemodynamic effect:** Increases both systolic and diastolic pressure while maintaining or slightly increasing heart rate - **Unique advantage:** Maintains cerebral perfusion pressure and coronary perfusion better than pure α-agonists ### Comparison of Perioperative Vasopressors | Agent | Mechanism | HR Effect | Onset | Duration | Clinical Use | Limitation | |-------|---|---|---|---|---|---| | **Ephedrine** | Indirect (releases NE) | ↑ (mild) | 5–10 min (IV) | 30–60 min | First-line periop | Tachyphylaxis, arrhythmias | | Phenylephrine | Direct α1 | ↓ (reflex) | 1–5 min | 15–20 min | Pure vasoconstriction | Reflex bradycardia, reduced CO | | Norepinephrine | Direct α + β1 | ↑ (mild) | 1–2 min | 5–10 min | Refractory shock | ICU use, not routine periop | | Methoxamine | Direct α1 | ↓↓ (marked) | 1–5 min | 15–20 min | Rarely used | Severe bradycardia, ↓ CO | **Clinical Pearl:** Ephedrine's **preservation of cardiac output** and **maintained heart rate** make it ideal for general anaesthesia, where spinal/epidural-induced hypotension is common. A single IV bolus (6–12 mg) rapidly restores blood pressure without causing reflex bradycardia. **Mnemonic — EPHEDRINE PERIOP ADVANTAGE:** "**E**phedrine **E**ven **E**nhances **E**fficiency" → Effective, Easy to use, Economical, Endogenous catecholamine release. ### Why Ephedrine Is Most Common in Indian Practice 1. **Dual α + β effects** — increases both systolic and diastolic pressure while maintaining cardiac output 2. **Longer duration** (30–60 min) — fewer repeated doses needed during surgery 3. **Oral availability** — can be used preoperatively for hypotensive patients (e.g., 25 mg PO 30 min before surgery) 4. **Cost-effective** — inexpensive, widely available in all Indian hospitals 5. **Safety in regional anaesthesia** — preferred over phenylephrine for spinal/epidural hypotension (avoids reflex bradycardia) 6. **Guideline endorsement** — recommended as first-line vasopressor in perioperative hypotension by Indian Society of Anaesthesiologists ### When Other Agents Are Preferred - **Phenylephrine:** Pure vasoconstriction needed (e.g., severe tachycardia, hyperdynamic state) - **Norepinephrine:** ICU setting with septic shock or cardiogenic shock - **Methoxamine:** Rarely used; only when absolute bradycardia prevention is needed [cite:KD Tripathi 8e Ch 12]