Concomitant use w/ anti-bacterials, immunosuppressants, parenteral pentamidine, antineoplastics & diuretics. May enhance effects of neuromuscular blocking agents & increase toxicity of digitalis glycosides. May enhance depletion of K & immunosuppresive effects w/ corticosteroids. Procaine HCl & lidocaine HCl, ranitidine HCl, antihistamines & vit.