Since this drug affects the immune system of the recipient, certain diseases can end up being exacerbated by this treatment. Pets with a fungal disease, or viremia, should never be put on dexamethasone. Due to teratogenic effects of the drug, pregnant pets should only take dexamethasone if the benefits greatly outweigh the inherent risk to the fetus. Pets that have been taking dexamethasone long term, or in high doses, should be tapered off the drug slowly. Patients with congestive heart failure, diabetes, or osteoporosis should take dexamethasone with caution. Unless it is an emergency, pets with kidney disease, GI ulcers, or hyperadrenocorticism should not take dexamethasone.
Dexamethasone should never be taken with other corticosteroids, NSAIDs, or immunosuppressants, as this might exacerbate the potential for negative side effects. Taking antacids may reduce the rate at which dexamethasone is absorbed. Patients with myasthenia gravis taking anticholinesterase and dexamethasone might suffer from profound muscle weakness. Anticoagulants may be increased or decreased in effectivity. Dexamethasone decreases the effects of bacteriostatic antibiotics. Taking with estrogen agents will likely potentiate the effects of dexamethasone. Macrolide antibiotics increase or prolong the effects of dexamethasone. Potassium depleting diuretics and Amphotericin B will likely cause hypokalemia.
Thanks to the diminished immune response caused by dexamethasone, vaccinationsc should not be given to patients taking the treatment. Taking aspirin or acetylsalicylic acid might reduce salicylate levels. Taking cyclophosphamide will decrease the rate at which it (cyclophosphamide) can be metabolized. Same with cyclosporine. Taking digoxin might cause hypokalemia and digitalis, with an increased risk of digitalis toxicity. Dexamethasone might increase the required amount of insulin needed in diabetic patients. Ketoconazole might increase or prolong the glucocorticoid activity. Taking with mitotane might alter the recipients metabolism, and phenobarbital, phenytoin sodium, and rifampin will all have effects on the bodies ability to metabolize glucocorticoids, like dexamethasone.