Comparison of five regimens for oral administration of medication to induce sedation in dogs prior to euthanasia.

OBJECTIVE: To compare regimens for oral administration of medication to induce sedation in dogs prior to euthanasia.
DESIGN: Prospective randomized clinical study. ANIMALS: 37 dogs. PROCEDURE: Groups and medications were as follows: group 1, acepromazine (n = 8); group 2, tiletamine-zolazepam (8); group 3, tiletamine-zolazepam and acepromazine (8); group 4, tiletamine-zolazepam and butorphanol (6); and group 5, pentobarbital sodium (7). Capsules or tablets were placed in each dog's food. Sedation was scored at 3-minute intervals after consumption of medication for at least 60 minutes. Dogs with signs of persistent or progressive sedation were observed for 90 minutes.
RESULTS: Only 2 dogs in group 1 became slightly ataxic. All group-2 dogs were slightly ataxic, and 4 of 8 became laterally recumbent (mean time to lateral recumbency, 62 minutes). Seven of 8 group-3 dogs became sternally recumbent, and 6 of these dogs became laterally recumbent (mean, 48.6 minutes). Four of 6 group-4 dogs were slightly or moderately ataxic, and 1 of these dogs became laterally recumbent (mean, 48 minutes). One dog in group 5 was not affected by the medication, but all other group-5 dogs became laterally recumbent (mean, 59 minutes). CLINICAL IMPLICATIONS: Of the medications evaluated, tiletamine-zolazepam and acepromazine at dosages of approximately 20 mg/kg (9.1 mg/lb) and 2 mg/kg (0.91 mg/lb), respectively, or pentobarbital sodium alone (63.2 +/- 5.1 mg/kg [28.7 +/- 2.3 mg/lb]) most consistently induced profound sedation and lateral recumbency after oral administration to dogs.