Effects of epidural clonidine and neostigmine following intrathecal labour analgesia: a randomised, double-blind, placebo-controlled trial.

BACKGROUND: The limited duration of spinal labour analgesia combined with problems associated with maintenance of epidural analgesia, have prompted the search for combinations that could prolong spinal analgesia. A randomised, double-blind trial was carried out to test the hypotheses (a) that initial spinal labour analgesia is prolonged by administering clonidine and neostigmine epidurally whilst (b) the hourly local anaesthetic consumption is reduced.

METHODS: Seventy labouring patients received spinal analgesia with ropivacaine and sufentanil. Fifteen minutes after spinal injection, 10 mL of study solution was administered epidurally. The study solution was plain saline or neostigmine 500 microg combined with clonidine 75 microg. Outcome parameters were duration of spinal analgesia, local anaesthetic consumption and number of patients delivering without additional epidural analgesia.

RESULTS: Epidural clonidine and neostigmine significantly prolonged initial analgesia: 144 (105-163) min vs. 95 (70-120) min in the placebo group and reduced hourly ropivacaine consumption: 7.5 (3.0-11.9) mg vs. 12.7 (9.6-16.9) mg. More patients in the experimental group delivered before the first request for additional analgesia (9 vs. 2).

CONCLUSION: Epidural administration of neostigmine 500 microg and clonidine 75 microg, following the intrathecal injection of ropivacaine and sufentanil, prolongs analgesia and reduces hourly ropivacaine consumption.