Increased effect of metoprolol
- amiodarone, cimetidine, diltiazem, nifedipine, nicardipine, verapamil, flecainide, hydralazine, MAO inhibitors, quinidine, ciprofloxacin, propafenone, oral contraeptives, fluoxetine, sertraline.
Decreased effect of metoprolol - NSAIDS, salycylates, barbiturates, rifampin, clonidine.
The dosage and frequency depend upon the individuals metabolism and the drug being used.
There are no substitutes to beta-blockers.