Atenolol and chlorthalidone and Nifedipine interaction

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

Drug Interactions Atenolol and chlorthalidone may potentiate the action of other antihypertensive agents used concomitantly.

Calcium channel blockers may also have an additive effect when given with atenolol and chlorthalidone.

Concomitant Use of Calcium Channel Blockers Bradycardia and heart block can occur and the left ventricular end diastolic pressure can rise when beta- blockers are administered with verapamil or diltiazem.

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Patients recently withdrawn from beta-blockers may develop a withdrawal syndrome with increased angina, probably related to increased sensitivity to catecholamines.