STUDY ON THE MECHANISMS OF ACTION OF SODIUM MECLOFENAMIC ACID (MECLOMEN) A DOUBLE INHIBITOR OF THE ARACHIDONIC-ACID CASCADE

Meclofenamic acid sodium (Meclomen) was found to inhibit both the cycl ooxygenase and the lipoxygenase pathways of arachidonic acid metabolis m. It inhibited both 5-lipoxygenase and 15-lipoxygenase activities. Me clomen was also shown to interfere with leukotriene receptors or possi bly post-receptor mechanisms. In isolated lung parenchyma strip prepar ations Meclomen inhibited leukotriene C-4 and D-4 induced contractions , but had no effect on histamine induced contractions. Ibuprofen, napr oxen and indomethacin had no effect on lipoxygenases or on leukotriene receptors but were powerful inhibitors of cyclooxygenases.