Sir,

Drug errors can have severe consequences. Here we describe an inadvertent peribulbar injection of acetazolamide instead of local anaesthetic agent, prior to cataract surgery.

Case report

A 63-year-old male with glaucoma was to undergo right cataract surgery under peribulbar anaesthesia. Intravenous (IV) acetazolamide (500 mg in 10 ml) was planned for intra-operative use but had been drawn up pre-operatively. Eight millilitres of this solution were inadvertently given as a peribulbar injection by the anaesthetist (not one of the authors) instead of the anaesthetic agent. The patient complained of disproportionate pain during injection. The mistake was recognized and surgery deferred. On examination vision was maintained, but ocular motility was reduced by 50% in all directions of gaze. There was marked lid oedema with mild conjunctival chemosis. The patient was promptly given 200 ml of IV mannitol 20% to reduce the intraorbital pressure. An orbital opinion was sought and as there was no information in the literature or from the poisons unit regarding further management, the patient was given IV methyl prednisolone (500 mg) stat and prophylactic IV cefuroxime (750 mg) on an empirical basis and admitted for regular monitoring. Subsequently he was started on oral prednisolone (40 mg) for 5 days. His ocular motility recovered to normal and the lid oedema and chemosis settled in 48 h. A month later he underwent right cataract surgery. Eighteen months after the incidence his vision is 6/5 in the right eye with full ocular motility and no lid or orbital problems.

Comment

Some medications can cause severe soft tissue and skin necrosis when accidentally injected or extravasated into soft tissues. Extravasation of acetazolamide (a high-risk vesicant drug, pH 9.1) causing soft-tissue necrosis of the forearm has been reported once.1 No specific antidote is available to counteract acetazolamide. In this patient, IV methyl prednisolone may have had a role in the prevention of complications. The diluted acetazolamide (500 mg in 10 ml water) could be another factor. As a general rule, prevention is the cornerstone and avoiding similar problems can be achieved by using a clear labelling system2 and drawing up the required injection immediately before its administration.

Conflict of interest

The authors declare no conflict of interest.