Betamethasone: Concurrent use of phenobarbital, phenytoin, rifampin or ephedrine may enhance corticosteroid metabolism, reducing the therapeutic effects.
Patients concurrently receiving an estrogen should be observed for excessive corticosteroid effects.
Concurrent corticosteroid use with potassium-depleting diuretics may enhance hypokalemia. Concurrent corticosteroid use with cardiac glycosides may enhance the possibility of arrhythmias or digitalis toxicity associated with hypokalemia. Corticosteroids may enhance potassium depletion caused by amphotericin B. In all patients taking any of these drug therapy combinations, serum electrolyte determinations particularly potassium levels, should be closely monitored.
Concurrent corticosteroid use with coumarin-type anticoagulants may increase or decrease the anticoagulant effects, possibly requiring dosage adjustment.
Combined effects of noncorticosteroid anti-inflammatory drugs or alcohol with glucocorticoids may result in increased occurrence or severity of gastrointestinal ulceration.
Corticosteroid may decrease blood salicylate concentrations. Acetylsalicylic acid should be used cautiously in conjunction with corticosteroids in hypoprothrombinemia.
Dosage adjustments of an antidiabetic drug may be necessary when corticosteroids are given to diabetics.
Concomitant glucocorticoid therapy may inhibit the response to somatotropin.
Drug/Laboratory Test: Corticosteroids may affect the nitroblue tetrazolium test for bacterial infection and produce false-negative results.
Dexchlorpheniramine Maleate: Monoamine oxidase inhibitors (MAOIs) prolong and intensify the effects of antihistamines; severe hypotension may occur.
Concomitant use with alcohol, tricyclic antidepressants, barbiturates or other central nervous system depressants may potentiate the sedative effect of dexchlorpheniramine.
The action of oral anticoagulants may be inhibited by antihistamines.