Controlled retrospective study of the effects of eyedrops containing phenylephrine hydrochloride and scopolamine hydrobromide on mean arterial blood pressure in anesthetized dogs.
OBJECTIVE
To determine whether dogs that received eyedrops containing phenylephrine and scopolamine would have a higher mean arterial blood pressure (MAP) when anesthetized than would dogs that did not receive the eyedrops.


METHODS
37 nondiabetic and 29 diabetic dogs anesthetized for phacoemulsification and 15 nondiabetic dogs anesthetized for corneal ulcer repair (control dogs).


METHODS
Medical records were reviewed to identify study dogs. Dogs undergoing phacoemulsification received 2 types of eyedrops (10% phenylephrine hydrochloride and 0.3% scopolamine hydrobromide) 4 times during a 2-hour period prior to the procedure. Control dogs did not receive these eyedrops. Heart rate and MAP were measured before surgery in all dogs 10 and 5 minutes before, at the time of (t0), and 5 (t5) and 10 (t10) minutes after atracurium administration.


RESULTS
MAP was greater in the 2 groups that received the eyedrops than in the control group at t0 and t5; at t10, it was greater only for the nondiabetic dogs that received eyedrops. Nine nondiabetic dogs and 1 diabetic dog anesthetized for phacoemulsification had at least 1 MAP value>131 mm Hg; 73% of MAP values>131 mm Hg were detected within 10 minutes after atracurium administration. At no time did a control dog have an MAP value>131 mm Hg.


CONCLUSIONS
Anesthetized dogs pretreated with eyedrops containing phenylephrine and scopolamine had higher MAP values than dogs that did not receive the eyedrops, suggesting the drops caused hypertension. Atracurium may interact with the eyedrops and contribute to the hypertension.
Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA. mm459@cornell.edu
Manuel
M
Martin-Flores
Tara M
TM
Mercure-McKenzie
Luis
L
Campoy
Hollis N
HN
Erb
John W
JW
Ludders
Robin D
RD
Gleed
D000758:Anesthesia; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects*; D048909:Diabetes Complications / Q000662:veterinary; D004285:Dogs; D006339:Heart Rate / Q000187:drug effects; D009883:Ophthalmic Solutions / Q000494:pharmacology*; D018918:Phacoemulsification / Q000662:veterinary; D010656:Phenylephrine / Q000494:pharmacology*; D012189:Retrospective Studies; D012601:Scopolamine / Q000494:pharmacology*
D009883:Ophthalmic Solutions; D010656:Phenylephrine; D012601:Scopolamine