Cardiac and central nervous system toxicity with timolol eye drops in an infant: case report and discussion

An 8 month old boy on maintenance propranolol for paroxysmal supraventricular tachycardias presented with a depressed level of consciousness, bradycardia and hypotension, triggered by the accidental nasal administration of the ophthalmic β blocker timolol. Timolol eye drops are not licensed for use in children, and safety data has been derived mainly from adult studies. There is a theoretical possibility that children may be more vulnerable to the systemic side effects of ocularly applied agents because of their smaller body mass. A discussion of the mechanisms of how topical application of timolol led to adverse cardiac and central nervous system reactions in a child illustrates how topical agents can be serious players in paediatric drug toxicity.