Assessment of clonidine effect as premedicative drug on kidney function

To assess the effect of oral clonidine as a premedicative drug on 24-hour urine output, urine specific gravity, plasma renin activity as well as serum and urine electrolytes levels.

This prospective study was carried out on 60 women aged 20-40 years old undergoing repair of cystocoele-rectocoele perineorraphy under general anaesthesia in Asali Hospital in 2004 in Khorramabad, Iran. Subjects were randomly divided into two equal groups of 30 each. Group I and group II received clonidine tablet at the dose of 5 microg/kg and placebo tablet, respectively, 90 minutes before induction of general anesthesia. In this study, blood and urine samples were taken for laboratory measurements prior as well as 6 hours after taking the tablets. Differences between the two groups were compared through Mann-Whitney u-test, chi2 test and t-student test. P-value < 0.05 was considered statistically significant.

There were no significant changes before and after receiving tablets in urine and blood Na and K as well as urine specific gravity in group II (P > 0.05). Group I had higher urine Na and K level (P = 0.001), however, no differences had been shown in blood Na and K level (P > 0.05). Urine specific gravity was lower in group I after receiving tablet (P < 0.009). A significant increase in 24-hour urine output (P = 0.001) and a marked decrease in plasma renin activity was seen in group I (P = 0.001).

This study suggests that clonidine is a safe premedicative drug in anaesthesia and does not change the serum electrolytes levels.