Treatment with mefenamic acid delays wound healing

Abstract

Effects of mefenamic acid ingested onto the wound healing process were evaluated in terms of both blood flow in the wounded area and histopathologic changes in mice. On the experimental day 1, an incision was made in to the skin and closed with nylon thread. One group of mice received mefenamic acid at a dose of 100 mg/kg p.o. and the rest, receiving surgical treatment alone, served as the control. Blood flow was measured with a laser doppler flow meter (LDF). The results are as follows:
1. In the control, when the skin was incised and closed with nylon thread, blood flow in the wounded area was increased from experimental days 1 to 10.
2. In animals receiving mefenamic acid, blood flow was also increased for 10 days after the surgical treatment, but all of the increments were significantly smaller than the corresponding values in the control. On experimental day 1, blood flow in the experimental group was 37.1±5.2% smaller than that in the control. The rate of difference increased to 41.3±9.4% on experimental day 4, and then began to diminish on experimental day 5. It decreased to 8.4±3.0% on experimental day 10 (P<0.01).
3. Histopathologic study showed that injured tissues were repaired to the normal in the control, but the reparative process was lengthened in mice receiving mefenamic acid.
Changes in blood flow, as measured with the laser doppler flow meter, were consistent with the histopathologic findings. Both aspects of wound healing thus indicate that mefenamic acid, at the dose of 100 mg/kg, delayed wound healing in skin incision in mice.
When possible delay in postoperative wound healing is taken into account, conventional extraction of the stitches on the postoperative day 7 should be reconsidered in those patients treated with non-steroidal anti inflammatory agents.