Inhibition of the arachidonic acid pathway by several drugs. Steroids inhibit the production of arachidonic acid, thereby blocking the synthesis of leukotrienes and prostaglandins. Ketoprophen is believed to block the production of 5-lipooxygenase and cyclooxygenase. Aspirin and nonsteroidal anti-inflammatory drugs block the conversion of cyclo-oxygenase to prostaglandins and thromboxane A₂. Trilisate blocks theproduction of prostagandins (PG) E₂ and F₂, but not I₂ or thromboxane A₂. (©2001 D.J. Wilkie, used with permission.)