Synergistic effect of intraperitoneally administered calcium channel blockade and recombinant tissue plasminogen activator to prevent adhesion formation in an animal model.

Previous reports have shown the benefits of calcium channel blockers and recombinant tissue plasminogen activator to prevent postoperative adhesion formation in animal models. To assess the potential benefit of synergistic therapy for the prevention of postoperative adhesion formation, these agents were studied in a rabbit uterine horn model. Four groups of New Zealand White rabbits (n = 8 per group) had a bilateral devascularization injury to the uterine horns. Before closure saline solution, verapamil hydrochloride (2.5 mu/kg/hour), recombinant tissue plasminogen activator (4 mg total dose), or a combination of verapamil and recombinant tissue plasminogen activator at the stated doses were instilled by means of an Alzet osmotic pump x 200 hours. Adhesion scores were evaluated after this time period by estimating the total uterine horn surface involved in adhesions at a terminal laparotomy and by clinically grading the response to determine whether minimal adhesions formed. Results of the total uterine horn surface scores were (mean score +/- SE): saline solution, 44% +/- 3.7%; verapamil, 19% +/- 4.8%; recombinant tissue plasminogen activator, 11% +/- 3.6%; combined, 3% +/- 1% (p less than 0.01 to control and p less than 0.05 to single-drug therapy). Results of the number of animals per group with minimal adhesions were as follows: saline solution, 0; verapamil, 1; recombinant tissue plasminogen activator, 3; combined, 8 (P less than 0.01). These results show a synergistic benefit of verapamil and recombinant tissue plasminogen activator to prevent postsurgical adhesion formation when delivered via the intraperitoneal route.