Changes in intraocular pressure and pupil size following intramuscular administration of hydromorphone hydrochloride and acepromazine in clinically normal dogs

Objective To investigate the effects of intramuscularly administered hydromorphone hydrochloride and acepromazine on intraocular pressure (IOP) and pupil size (PS). Animals studied Seventeen dogs free of clinically relevant ocular abnormalities. Procedure Measurements of IOP and PS were obtained and the dogs were injected intramuscularly with hydromorphone (0.04-0.08 mg/kg) and acepromazine (0.04 mg/kg). Measurements of IOP and PS were repeated 10 min and 25 min later. Results Though a decreasing trend in IOP values was demonstrated, no significant difference was noted in IOP from the initial examination to examination following intramuscular administration of hydromorphone and acepromazine. Significant miosis was present in 16 of 17 dogs at 10 min and 25 min following administration of hydromorphone and acepromazine. Conclusion Hydromorphone (0.04-0.08 mg/kg) and acepromazine (0.04 mg/kg) cause significant miosis in dogs at 10 and 25 min following intramuscular administration.