Prednisoneinteractions

Amphotericin B Injection and Potassium-Depleting Agents When corticosteroids are administered concomitantly with potassium-depleting agents (e.g., amphotericin B, diuretics ), patients should be observed closely for development of hypokalemia. In addition, there have been cases reported in which concomitant use of amphotericin B and hydrocortisone was followed by cardiac enlargement and congestive heart failure. Antibiotics Macrolide antibiotics have been reported to cause a significant decrease in corticosteroid clearance (see PRECAUTIONS: Drug Interactions: Hepatic Enzyme Inducers, Inhibitors and Substrates ). Anticholinesterases Concomitant use of anticholinesterase agents (e.g., neostigmine, pyridostigmine ) and corticosteroids may produce severe weakness in patients with myasthenia gravis. If possible, anticholinesterase agents should be withdrawn at least 24 hours before initiating corticosteroid therapy. If concomitant therapy must occur, it should take place under close supervision and the need for respiratory support should be anticipated. Anticoagulants, Oral Coadministration of corticosteroids and warfarin usually results in inhibition of response to warfarin, although there have been some conflicting reports. Therefore, coagulation indices should be monitored frequently to maintain the desired anticoagulant effect. Antidiabetics Because corticosteroids may increase blood glucose concentrations, dosage adjustments of antidiabetic agents may be required. Antitubercular drugs Serum concentrations of isoniazid may be decreased. Bupropion Since systemic steroids, as well as bupropion, can lower the seizure threshold, concurrent administration should be undertaken only with extreme caution; low initial dosing and small gradual increases should be employed. Cholestyramine Cholestyramine may increase the clearance of corticosteroids. Cyclosporine Increased activity of both cyclosporine and corticosteroids may occur when the two are used concurrently. Convulsions have been reported with this concurrent use. Digitalis Glycosides Patients on digitalis glycosides may be at increased risk of arrhythmias due to hypokalemia. Estrogens, Including Oral Contraceptives Estrogens may decrease the hepatic metabolism of certain corticosteroids, thereby increasing their effect. Fluoroquinolones Postmarketing surveillance reports indicate that the risk of tendon rupture may be increased in patients receiving concomitant fluoroquinolones (e.g., ciprofloxacin, levofloxacin ) and corticosteroids, especially in the elderly. Tendon rupture can occur during or after treatment with quinolones. Hepatic Enzyme Inducers, Inhibitors and Substrates Drugs which induce cytochrome P450 3A4 (CYP 3A4) enzyme activity (e.g., barbiturates, phenytoin, carbamazepine, rifampin ) may enhance the metabolism of corticosteroids and require that the dosage of the corticosteroid be increased. Drugs which inhibit CYP 3A4 (e.g., ketoconazole, itraconazole, ritonavir, indinavir, macrolide antibiotics such as erythromycin ) have the potential to result in increased plasma concentrations of corticosteroids. Glucocorticoids are moderate inducers of CYP 3A4. Coadministration with other drugs that are metabolized by CYP 3A4 (e.g., indinavir, erythromycin ) may increase their clearance, resulting in decreased plasma concentration. Ketoconazole Ketoconazole has been reported to decrease the metabolism of certain corticosteroids by up to 60%, leading to increased risk of corticosteroid side effects. In addition, ketoconazole alone can inhibit adrenal corticosteroid synthesis and may cause adrenal insufficiency during corticosteroid withdrawal. Nonsteroidal Anti-Inflammatory Agents (NSAIDS) Concomitant use of aspirin (or other nonsteroidal anti-inflammatory agents ) and corticosteroids increases the risk of gastrointestinal side effects. Aspirin should be used cautiously in conjunction with corticosteroids in hypoprothrombinemia. The clearance of salicylates may be increased with concurrent use of corticosteroids; this could lead to decreased salicylate serum levels or increase the risk of salicylate toxicity when corticosteroid is withdrawn. Phenytoin In postmarketing experience, there have been reports of both increases and decreases in phenytoin levels with dexamethasone coadministration, leading to alterations in seizure control. Phenytoin has been demonstrated to increase the hepatic metabolism of corticosteroids, resulting in a decreased therapeutic effect of the corticosteroid. Quetiapine Increased doses of quetiapine may be required to maintain control of symptoms of schizophrenia in patients receiving a glucocorticoid, a hepatic enzyme inducer. Skin Tests Corticosteroids may suppress reactions to skin tests. Thalidomide Coadministration with thalidomide should be employed cautiously, as toxic epidermal necrolysis has been reported with concomitant use. Vaccines Patients on corticosteroid therapy may exhibit a diminished response to toxoids and live or inactivated vaccines due to inhibition of antibody response. Corticosteroids may also potentiate the replication of some organisms contained in live attenuated vaccines. Routine administration of vaccines or toxoids should be deferred until corticosteroid therapy is discontinued if possible (see WARNINGS: Infection: Vaccination ).