PARENTERAL ANTICHOLINERGICS IN DOGS WITH NORMAL AND ELEVATED INTRAOCULAR-PRESSURE

Dogs given parenteral anticholinergic drugs have been thought to be at risk for development or exacerbation of elevated intraocular pressure (IOP). In a randomized, blinded, placebo-controlled study, we evaluat ed the effect of intramuscular glycopyrrolate (0.01 mg/kg) on pupil di ameter and IOP in unanesthetized normal dogs. Treatment with glycopyrr olate did not change pupil diameter or IOP from baseline, nor were the re differences between glycopyrrolate and saline-treated (control) dog s. In addition, the authors retrospectively reviewed the medical recor ds of 2,828 dogs undergoing general anesthesia between April 1987 and September 1990 to determine if there was an association between parent eral anticholinergic medication and postanesthetic elevation in IOP. T he authors also determined the frequency of bradycardia requiring anti cholinergic therapy during anesthesia in dogs with glaucoma. Of the 2, 828 cases reviewed, the records of 46 dogs coded for glaucoma were exa mined in detail. The 46 dogs underwent 62 episodes of anesthesia, with 23 episodes including exposure to an anticholinergic drug. An increas e in IOP from preanesthetic to postanesthetic measurement occurred in three dogs. One of these dogs received anticholinergic medication for bradycardia during anesthesia. The postanesthetic elevation in IOP in this dog was probably not drug related. Preanesthetic anticholinergic administration did not affect the incidence of anticholinergic adminis tration for bradycardia during the anesthetic episode. Anticholinergic therapy during anesthesia was more frequent when the preanesthetic me dication included an opiate drug. These studies do not indicate an ass ociation between parenteral anticholinergic administration and elevati ons in IOP.