Effects of diphenhydramine HCl and methylprednisolone in the prevention of abdominal adhesions

Objective: The purpose of this study was to determine the effects of diphenhydramine hydrochloride and methylprednisolone in peritoneal adhesions. Materials and methods: Forty-eight male rats were used in the study. The rats were anesthetized by 5 mg/kg ketamine hydrochloride. After opening the abdomen, 10 longitudinal incisions of 2 to 3 cm in length were made on the right parietal peritoneum, and a 2 cm2 peritoneal layer was excised from the left abdominal wall. The abdomen was closed with 3/0 silk suture. Group I was the control group, group II was given 10 mg/kg diphenhydramine intravenously, group III was given 20 mg/kg methylprednisolone intravenously, and group IV was administered both of the drugs in the above doses. A blood sample of 2 mL was taken from the rats on the 14th day after the operation. The animals were then sacrificed. The abdomen was opened and abdominal adhesions were examined. A tissue sample of 1 g was taken from the abdominal incision line. Albumin, zinc, and hemoglobin levels and leucocyte counts in the blood were determined as well as hydroxyproline levels in the tissue. Results: Numbers of adhesions were as follows: 9 in group I, 3 in group II, and 2 in group III. No adhesion was observed in group IV. Albumin, zinc, and hemoglobin levels and leucocyte counts were found to be similar in all groups. Hydroxyproline levels in the tissue were significantly lower in groups III and IV than in groups I and II (P <0.05). Conclusions: Diphenhydramine and methylprednisolone reduced postoperative adhesions significantly in rats. Further investigations are needed in order to use these drugs as antiadhesive agents in humans.