Prolonged bradycardia and hypotension after neostigmine administration in a patient receiving atenolol.

A 78-year-old woman admitted for an elective hip operation was maintained on atenolol for control of her hypertension. She received neostigmine and atropine for reversal of muscle relaxation at the end of general anaesthesia. She then developed prolonged bradycardia and hypotension which necessitated the use of adrenaline and isoprenaline. Such an adverse reaction with atenolol has not been described previously.