About Indomethacin NSAID, Indole derivative, Anti-inflammatory, potent antipyretic and analgesic. Mechanism of Action of Indomethacin Indomethacin acts by inhibition of Prostaglandin (PGs) synthesis and their release at the site of injury. Prostaglandins cause tenderness and amplify the action of other algesics. Indomethacin does not affect the tenderness induced by PGs but block the pain producing mechanism induced by inflammatory mediators by inhibiting the enzyme cyclo-oxygenase. Interactions for Indomethacin Anticoagulants: May prolong prothrombin time. Instruct patients to watch for signs & symptoms of bleeding. Beta-Blockers: Antihypertensive effect may be blunted. Cyclosporine: Nephrotoxicity of both agents may be increased. Digoxin: Serum digoxin levels may be increased by ibuprofen and indomethacin. Hydantoins: Serum hydantoin levels increased resulting in increased pharmacological and toxic effects. Lithium: Serum lithium levels may be increased.