Analgesic and hemodynamic effects of intrathecal clonidine as the sole analgesic agent during first stage of labor - A dose-response study

Background: Intrathecal clonidine produces dose-dependent postoperative ana lgesia and enhances labor analgesia from intrathecal sufentanil, The author s evaluated the dose-response potency of intrathecally administered clonidi ne by itself during first stage of labor with respect to analgesia and mate rnal and fetal side effects, Methods: Thirty-six parturients requesting labor analgesia were included in this prospective, randomized, double-blind study, Parturients with < 6 cm cervical dilatation received either 50, 100, or 200 mu g intrathecal clonid ine, The authors recorded visual analog pain score (VAPS), maternal blood p ressure and heart rate, ephedrine requirements, and sedation at regular int ervals and fetal heart rate tracings continuously. Duration of analgesia wa s defined as time from intrathecal clonidine administration until request f or additional analgesia. Results: Clonidine produced a reduction in VAPS with all three doses. The d uration of analgesia was significantly longer its patients receiving 200 mu g (median, 143; range, 75-210 min) and 100 mu g(median, 118; range, 60-180 min) than 50 mu g (median, 45; range, 25-150 min), and VAPS was lower in t he 200-mu g than in the 50-mu g group. In the 200-mu g group, hypotension r equired significantly more often treatment with ephedrine than in the other groups, No adverse events or fetal heart rate abnormalities occurred. Conclusions Fifty to 200 Erg intrathecal clonidine produces dose-dependent analgesia during first stage of labor. Although duration and quality of ana lgesia were more pronounced with 100 and 200 mu g than with 50 mu g, the hi gh incidence of hypotension requires caution with the use of 200 mu g for l abor analgesia.