Weight and gender differences in recovery time after thiopental anesthesia interaction with phenylbutazone in dogs

Objectives: Anesthesia is used for a wider range of circumstances in animals than in people and often involves the administration of several drugs belonging to different classes. Recovery from general anesthesia is a critical phase and dependent on Patient gender,age, weight and drug interaction may be important factors influence recovery from general anesthesia. NSAIDs have the potential for both pharmacokinetic and pharmacodynamic interactions with injectable anesthetic drugs. The purpose of this research was to investigate the possible interaction between phenylbutazone and sodium thiopental in male and female dogs.Materials and methods: Fourty one mixed breed dogs were randomly divided into two control and experimental groups. Normal saline and sodium thiopental were intravenously administered to animals in the control group. Equivalent dose of sodium thiopental was administered following the injection of phenylbutazone via the same route. After anesthesia, time intervals needed for the return of pulpebral reflex, opening of eyes, tongue movement, extension of the limbs, head and neck movement, sitting position, trying to stand, imbalanced walking, and normal walking were recorded.Results: Results show that, the average time periods in the experimental group were generally more than those in the control group in two sex. It was also shown that the duration of the above parameters were significantly higher in heavier female dog ( 18kg) compared to the male dog( 18kg). Conclusion: Female have a larger proportion of body fat and smaller water content than male dogs. This is especially the interaction with the phenylbutazone may be due to an increase in the unbound form of thiopental and a quicker distribution of the drug into the brain and, therefore, a greater duration of thiopental action. When rapid onset of or short duration of action is very important, gender-modified dosing may be considered..