Paracetamol: Reduced absorption of cholestyramine within 1 hr of administration. Accelerated absorption with metoclopramide. Aceclofenac: May increase the plasma concentrations of lithium and digoxin. Increased nephrotoxicity with diuretics. Serum-potassium should be monitored when used with potassium-sparing diuretics. May enhance activity of anticoagulants. May increase plasma methotrexate levels leading to toxicity if administered within 2-4 hr of methotrexate admin.