Drug Interactions When administered concomitantly with midodrine, cardiac glycosides may enhance or precipitate bradycardia, A.V. block or arrhythmia. The risk of hypertension increases with concomitant administration of drugs that increase blood pressure (phenylephrine, pseudoephedrine, ephedrine, dihydroergotamine, thyroid hormones, or droxidopa). Avoid concomitant use of drugs that increase blood pressure. If concomitant use cannot be avoided, monitor blood pressure closely. Avoid use of MAO inhibitors or linezolid with midodrine. Midodrine has been used in patients concomitantly treated with salt-retaining steroid therapy (i.e., fludrocortisone acetate), with or without salt supplementation. The potential for supine hypertension should be carefully monitored in these patients and may be minimized by either reducing the dose of fludrocortisone acetate or decreasing the salt intake prior to initiation of treatment with midodrine. Alpha-adrenergic blocking agents, such as prazosin, terazosin, and doxazosin, can antagonize the effects of midodrine. Potential for Drug Interaction It appears possible, although there is no supporting experimental evidence, that the high renal clearance of desyglymidodrine (a base) is due to active tubular secretion by the base-secreting system also responsible for the secretionof such drugs as metformin, cimetidine, ranitidine, procainamide, triamterene, flecainide, and quinidine. Thus there may be a potential for drug-drug interactions with these drugs.
