Influence of epidural morphine or tramadol in gastrointestinal transit of horses

ABSTRACT Opioids provide analgesia and are used in veterinary, however there is a restriction regarding the use of these drugs in horses, because may lead to ileus, but epidural opioids minimize those side effects. Eight healthy horses were used in three experimental groups, to evaluate the gastrointestinal influence after epidural morphine (0.2mg / kg), tramadol (1.0mg / kg) or NaCl 0.9%. Intestinal transit was evaluated with the administration of Lipe® (purified enriched isolated lignin) and later analyzed in the feces. Feces were collected before the epidural and at intervals up to 48 hours after the beginning of the experiment. The data were analyzed by a one-way analysis of variance or Friedman or Kruskal-Wallis and Student-Newman Keuls test as a post hoc. A value of P≤ 0.05 was considered significant. Epidural morphine or tramadol did not change the mean time for retention of the liquid phase, passage rate, and the transit time of the marker used. In conclusion, epidural morphine or tramadol does not change gastrointestinal transit.