A 62-year-old male with chronic kidney disease (eGFR 25 mL/min) is scheduled for elective abdominal surgery. Regarding the choice and use of muscle relaxants in this patient, all of the following are appropriate EXCEPT:

Explanation

## Muscle Relaxant Selection in Chronic Kidney Disease ### Renal Elimination and Drug Clearance **Key Point:** In renal failure, muscle relaxants that depend on renal elimination must be avoided. Agents with organ-independent clearance (Hofmann elimination, ester hydrolysis) or hepatic metabolism are preferred. ### Muscle Relaxant Metabolism in CKD | Agent | Elimination Route | Safe in CKD? | Notes | |-------|-------------------|--------------|-------| | **Atracurium** | Hofmann + ester hydrolysis | ✓ Yes | Organ-independent; no dose adjustment needed | | **Cisatracurium** | Hofmann elimination | ✓ Yes | Organ-independent; preferred in severe renal failure | | **Rocuronium** | Hepatic (70%) + renal (30%) | ⚠ Caution | 30% renal elimination; prolonged duration in CKD | | **Vecuronium** | Hepatic (80%) + renal (20%) | ⚠ Caution | 20% renal elimination; may accumulate | | **Succinylcholine** | Plasma cholinesterase | ✗ Avoid | Risk of severe hyperkalaemia in renal failure | | **Pancuronium** | Renal (80%) | ✗ Avoid | Heavily dependent on renal elimination | ### Why Rocuronium is NOT Ideal in CKD **High-Yield:** Although rocuronium is primarily metabolised by the liver (70%), approximately **30% is excreted unchanged in the urine**. In severe renal impairment (eGFR 25), this renal clearance is significantly reduced, leading to: - Prolonged duration of action - Risk of recurarisation - Need for dose reduction and extended dosing intervals The statement "rocuronium is eliminated by the liver and does not require renal excretion" is **FALSE** — it does have significant renal elimination. ### Clinical Pearl: Succinylcholine in CKD **Warning:** Succinylcholine causes release of potassium from muscle (0.5–1.0 mEq/L increase). In CKD patients with baseline hyperkalaemia or impaired potassium excretion, this can precipitate life-threatening hyperkalaemia and cardiac arrhythmias. It is contraindicated unless potassium is known to be normal and the patient is not at high risk. ### Hofmann Elimination **Mnemonic:** **HATCH = Hofmann And Temperature-dependent Clearance in Healthy organs** — Atracurium and cisatracurium undergo temperature- and pH-dependent degradation in plasma and tissues, independent of organ function. ### Recommended Approach in This Patient 1. **First choice:** Cisatracurium (organ-independent, no accumulation) 2. **Alternative:** Atracurium (organ-independent, but produces histamine release) 3. **Avoid:** Rocuronium (30% renal), succinylcholine (hyperkalaemia risk), pancuronium (80% renal)