Tolmetin

Drug Interactions ACE Inhibitors Reports suggest that NSAIDs may diminish the antihypertensive effect of ACE Inhibitors. This interaction should be given consideration in patients taking NSAIDs concomitantly with ACE Inhibitors. Aspirin ​​​​​​​As with other NSAIDs, concomitant administration of tolmetin sodium and aspirin is not generally recommended because of the potential of increased adverse effects. Diuretics ​​​​​​​ Clinical studies, as well as post-marketing observations have shown that NSAIDs can reduce the natriuretic effect of furosemide and thiazides in some patients. This response has been attributed to inhibition of renal prostaglandin synthesis.

During concomitant therapy with NSAIDs, the patient should be observed closely for signs of renal failure, as well as to assure diuretic efficacy. Lithium NSAIDs have produced an elevation of plasma lithium levels and a reduction in renal lithium clearance. The mean minimum lithium concentration increased 15% and the renal clearance was decreased by approximately 20%. These effects have been attributed to inhibition of renal prostaglandin synthesis by the NSAID. Thus, when NSAIDs and lithium are administered concurrently, subjects should be observed carefully for signs of lithium toxicity.

Methotrexate NSAIDs have been reported to competitively inhibit methotrexate accumulation in rabbit kidney slices. This may indicate that they could enhance the toxicity of methotrexate. Caution should be used when NSAIDs are administered concomitantly with methotrexate. Warfarin The effects of warfarin and NSAIDs on GI bleeding are synergistic, such that users of both drugs together have a risk of serious GI bleeding higher than users of either drug alone. The in vitro binding of warfarin to human plasma proteins is unaffected by tolmetin, and tolmetin does not alter the prothrombin time of normal volunteers.

However, increased prothrombin time and bleeding have been reported in patients on concomitant tolmetin and warfarin therapy. Therefore, caution should be exercised when administering tolmetin to patients on anticoagulants. Hypoglycemic Agents In adult diabetic patients under treatment with either sulfonylureas or insulin there is no change in the clinical effects of either tolmetin or the hypoglycemic agents. Drug/Laboratory Test Interactions The metabolites of tolmetin sodium in urine have been found to give positive tests for proteinuria using tests which rely on acid precipitation as their endpoint (e.g., sulfosalicylic acid).

No interference is seen in the tests for proteinuria using dye-impregnated commercially available reagent strips (e.g., Albustix ® , Uristix ® , etc.). Drug-Food Interactions In a controlled single-dose study, administration of tolmetin with milk had no effect on peak plasma tolmetin concentrations, but decreased total tolmetin bioavailability by 16%. When tolmetin was taken immediately after a meal, peak plasma tolmetin concentrations were reduced by 50% while total bioavailability was again decreased by 16%.

Pregnancy ]. Laboratory Tests Because serious GI tract ulcerations and bleeding can occur without warning symptoms, physicians should monitor for signs or symptoms of GI bleeding. Patients on long-term treatment with NSAIDs should have their CBC and a chemistry profile checked periodically. If clinical signs and symptoms consistent with liver or renal disease develop, systemic manifestations occur (e.g., eosinophilia, rash, etc.) or if abnormal liver tests persist or worsen, tolmetin should be discontinued.

Nursing Mothers Tolmetin sodium has been shown to be secreted in human milk. Because of the potential for serious adverse reactions in nursing infants from tolmetin sodium, a decision should be made whether to discontinue nursing or to discontinue the drug, taking into account the importance of the drug to the mother.