Abstract

Piperazine citrate produced a dose-dependent decrease in the blood pressure of the anaesthetized cat. Both 15 mg and 30 mg/kg piperazine showed average significant reduction in blood pressure of 29.8 ± 1.65 and 78.3 ± 3.18 mm Hg respectively. The effect produced in each case was transient and returned to baseline value within 2 min. The reduction in blood pressure caused by piperazine 30 mg/kg was statistically significant compared to the average due to piperazine 15 mg/kg (P < 0.0001). The maximum falls over the baseline blood pressure were also determined to be 34 and 82 mm Hg respectively. Adrenaline 5 mg increased the blood pressure of the cat by 68 mmHg and this effect was antagonized by equipotent doses of piperazine, nifedipine and propranolol to varying degrees. The antagonism produced by equipotent doses of piperazine (15 mg/kg) or nifedipine (200 mg/kg) to blood pressure elevation by adrenaline was quite small (8.8%), compared to propranolol (10mg) which antagonized the vasopressive action by as much as 26.5% (68 - 50 mmHg). Piperazine although severely reducing the blood pressure when given intravenously to the anaesthetized cat as shown in this study, may not be an effective antihypertensive agent as its hypotensive effect is always very transient. This would rather be seen as an untoward effect and in any event that may demand that piperazine be given intravenously, the patients should be warned of hypotension and dizziness as possible adverse effects.

Key words: Piperazine citrate, anaesthetized cat, blood pressure.