Breaking the block: Sugammadex as the last resort for refractory vecuronium-induced neuromuscular blockade in a patient receiving hydroxychloroquine

Dear Editor, Hydroxychloroquine (HCQ), a 4-aminoquinoline derivative, is commonly prescribed for autoimmune disorders such as systemic lupus erythematosus (SLE). While its immunomodulatory effects are well documented, its potential interactions with neuromuscular blocking agents (NMBAs) remain underappreciated in anaesthetic practice. We report a case of delayed recovery from neuromuscular blockade in a young female patient on chronic HCQ therapy, likely due to pharmacodynamic interaction with vecuronium. A 26-year-old female, weighing 70 kg and diagnosed with SLE, was scheduled for elective laparoscopic cystectomy under general anaesthesia. Her pre-anaesthetic evaluation was unremarkable, with no other comorbidities or prior anaesthetic exposures. She was receiving oral HCQ 400 mg daily as part of long-term management. In the operating room, standard monitors were attached. Neuromuscular monitoring was done using the Train of Four (TOF). Anaesthesia was induced using intravenous (IV) propofol (100 mg) and fentanyl (100 µg), followed by vecuronium (6 mg, approximately 0.1 mg/kg) to facilitate tracheal intubation (TOF count 0). Anaesthesia was maintained with oxygen, air, and sevoflurane under controlled ventilation. The intra-operative period was uneventful, with stable haemodynamics. Approximately 2 L of crystalloids were administered, and the blood loss was estimated to be 250 mL. At the conclusion of surgery, IV paracetamol (1 g) and ondansetron (4 mg) were administered. Neuromuscular blockade reversal was initiated using IV neostigmine (3.5 mg) and glycopyrrolate (0.6 mg) at a TOF ratio of