Extremely prolonged neuromuscular blockade following a single dose of rocuronium in a dog

Rocuronium is a non‐depolarising neuromuscular block drug extensively used in canine patients due to its favourable characteristics, including the fastest onset of action among all non‐depolarising neuromuscular blocking agents, lack of active metabolites and intermediate duration of effect. Although rocuronium elimination is relatively independent of kidney function, in the past few years, a growing number of reports describing a prolonged duration of the effect of rocuronium in human patients with renal failure have been published. However, to date, the mechanism behind this phenomenon is unclear. The present case describes the development of extremely prolonged neuromuscular blockade (>5 hours) following a single dose of 0.5 mg/kg rocuronium in a female English bulldog with renal disease where neostigmine failed to provide adequate reversal, which was only subsequently achieved following administration of sugammadex. Aside from renal disease, other possible causes of this prolonged duration (relative drug overdose, hypoalbuminaemia, co‐administered drugs, neostigmine‐induced neuromuscular blockade and idiosyncratic reaction to rocuronium) are also discussed.