Metoprolol and hydrochlorothiazide and Nifedipine interaction

Digitalis, Clonidine, and Calcium Channel Blockers: Digitalis glycosides, clonidine, diltiazem and verapamil slow atrioventricular conduction and decrease heart rate.

Because of its relative beta 1 cardio-selectivity, however, metoprolol tartrate may be used in patients with bronchospastic disease who do not respond to, or cannot tolerate, other antihypertensive treatment.

These responses have usually occurred during initial titration or at the time of subsequent upward dosage adjustment, and may be more likely in patients using concomitant beta-blockers.

Severe hypotension and/or increased fluid volume requirements have been reported in patients who received immediate-release capsules together with a beta-blocking agent and who underwent coronary artery bypass surgery using high-dose fentanyl anesthesia.

The interaction with high-dose fentanyl appears to be due to the combination of nifedipine and a beta-blocker, but the possibility that it may occur with nifedipine alone, with low doses of fentanyl, in other surgical procedures, or with other narcotic analgesics cannot be ruled out.

Beta-Blocker Withdrawal When discontinuing a beta-blocker it is important to taper its dose, if possible, rather than stopping abruptly before beginning nifedipine.

Patients recently withdrawn from beta-blockers may develop a withdrawal syndrome with increased angina, probably related to increased sensitivity to catecholamines.