Interactions between metoprolol and fluoxetine

Dear Ask The Doctor: I've been taking 60 mg cymbalta (fluoxetine) daily for 2 months for general anxiety with good success. I Recently experienced angina when exercising and later during a supervised "stress test" my doctore prescribed 25 mg metoprolol twice a day and 150mg aspirin a day while awaiting cardio angiogram. I notice a few mentions online of possible interactions between metoprolol and fluoxetine. Is it safe to commence both meds together or should I ask the dr for an alternative beta blocker? If I do get some interaction, which drug should I stop first, and in what manner should I taper off? thanks!!!

Dear Brad: You can take both these medications together as they do not interact with each other. However metoprolol is metabolised by the liver ( the P450 enzymes ) and fluoxetine inhibits these enzymes and thus may lead to slower metabolisation of the metoprolol. This should not cause any side effects but you will have to remember not to take extra doses of the metoprolol than what has been prescribed to you. All the best.