Drugs that can lower cyclosporine blood concentrations: barbiturates, acylmalazine, phenytoin sodium, neomycin III, sulfadimethoxine IV, rifampin, octreotide, probucol, sulfamethoxazole IV. Drugs that can increase the blood concentration of cyclosporine: chloroquine, macrolide antibiotics (erythromycin, crossamycin, puromycin), ketoconazole, fluconazole and itraconazole, diltiazem, nicardipine, verapamil, metoclopramide, oral contraceptives, danazol, methylprednisolone (high dose), allopurinol, amiodarone, bile acids and their derivatives, doxycycline, propafenone. Other related drug interactions: Sandimmune may decrease the clearance of digoxin, colchicine, lovastatin and prednisolone. This can lead to digoxin toxicity as well as increased potential muscle toxicity (causing muscle pain and weakness), myositis and rhabdomyolysis from lovastatin and colchicine. When this product is used in combination with NSAIDs with high first-pass effect, the latter should be used at a lower dose. Careful clinical monitoring is required if neostigmine is used in combination with digoxin, colchicine or lovastatin, so that toxic effects can be detected early and the dose can be reduced or discontinued. Food interactions: The bioavailability of cyclosporine can be improved when this product is taken together with grapefruit juice.