Table 2.

Summary of drug-drug interaction for 5-aminosalicylic acid (5-ASA/mesalazine) derivatives, corticosteroids and immunomodulators

Drug class	Interactions
5-ASA derivatives	5-ASA increases the anticoagulant activity of warfarin 5-ASA increases the risk of leukopenia if used in combination with thiopurines Mesalazine reduces serum concentration (and efficacy) of digoxin Mesalazine increases serum concentration (and the risk of adverse effects) of hydralazine and second generation of anti-tuberculosis drugs 5-ASA concentration increases if used with methotrexate
Corticosteroids	The efficacy of corticosteroids is reduced (due to increased clearance) with use of anti-epileptics Corticosteroids may increase the anticoagulant activity of warfarin Corticosteroids may reduce the effects of antidiabetic agents The use of calcium channel blockers may increase the serum concentration (and the risk of adverse effects) of corticosteroids Corticosteroids may increase the hypokalaemic effects of diuretics
Immunomodulators	Thiopurines reduce the anticoagulant activity of warfarin Thiopurines increase the risk of myelotoxicity if used with allopurinol (due to its xanthine oxidase-mediated action) Thiopurines increases the risk of leukopenia if used in combination with 5-ASA, clotrimazole and angiotensin-converting enzyme inhibitors Methotrexate concentration increases if used with 5-ASA derivatives, NSAIDs, penicillin's or tetracyclines Methotrexate may increase levels of theophyllines Methotrexate may alter the concentration of loop diuretics and vice-versa Azathioprine increases the effect of coumarin derivatives