A parturient with severe pre-eclampsia receiving magnesium sulphate infusion develops absent patellar reflexes and a respiratory rate of 8/min. The correct immediate management is:

• A Give naloxone and observe
• B Increase the infusion to control seizures
• C Stop the infusion and give calcium gluconate 10% intravenously ✓
• D Give flumazenil and continue the infusion

Explanation

Magnesium toxicity progresses predictably: loss of deep tendon reflexes occurs around 7 to 10 mEq/L, respiratory paralysis above 12 mEq/L, and cardiac arrest beyond 25 to 30 mEq/L. Absent reflexes with hypoventilation mandates stopping the infusion, supportive ventilation, and intravenous calcium gluconate 10%, the specific antagonist that reverses neuromuscular depression. Naloxone and flumazenil antagonise opioids and benzodiazepines respectively and have no role in magnesium toxicity.

Reference: Williams Obstetrics, 26th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.