Interaction entre Labétalol et Nifédipine

IV administration of non-dihydropyridine calcium-channel antagonists (e.g., verapamil) Hypersensitivity reactions, including anaphylaxis, to labetalol Bronchial asthma ( 4 )

Calcium Channel Blockers Coadministration of labetalol HCl with non-dihydropyrindine calcium-channel antagonists (e.g., verapamil) is contraindicated [see Contraindications (4) ].

Avoid the use of labetalol in patients receiving calcium-channel antagonists.

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Patients recently withdrawn from beta-blockers may develop a withdrawal syndrome with increased angina, probably related to increased sensitivity to catecholamines.