MRCP2-0823

MRCP2-0823

A 65-year-old man is admitted with a two day exacerbation of COPD. He arrives unwell and is started on steroids, nebulisers, aminophylline, ciprofloxacin and non invasive ventilation. He improves well and is weaned off the ventilation by his second day but starts to complain of palpitations and chest pain on the third day. He is usually well taking fostair twice a day. He used to smoke and drinks 20 units of alcohol a week.

You review him and find he has a pulse of 134 beats per minute that is irregular. He is clammy and his blood pressure is 96/76 mmHg. He has a chest that is wheezy throughout and is saturating at 91% with 2 litres of nasal cannulae oxygen. He is visibly trembling and feels nauseous. A cardiac monitor is attached showing an irregular narrow complex tachycardia.

Based on the given information, what is the probable cause of his drug toxicity?