It is always wise to research drug interactions, when we are taking Inhibitor type medications
I constantly have to remind myself to be aware of certain OTC medications that I buy without thinking about it
Im taking Stalevo, and check out the list of meds that interact with Entacapone, which is a COMT inhibitor
entacapone-oral (cont.)
DRUG INTERACTIONS: Tell your doctor of all prescription and nonprescription medication you may use, especially of: most MAO inhibitors (e.g., furazolidone, linezolid, moclobemide, phenelzine, procarbazine), isoproterenol, adrenalin (epinephrine), norepinephrine, dopamine, dobutamine, alpha-methyldopa, apomorphine, isoetharine, bitolterol, probenecid, cholestyramine, certain antibiotics (e.g., erythromycin, ampicillin, rifamin, chloramphenicol). According to the manufacturer, if you are prescribed the MAO inhibitor selegiline you may continue to take it while using entacapone. Also, report use of any medicine that can make you drowsy, such as: sedatives, tranquilizers, anti-anxiety medicine, anti-seizure drugs, narcotic pain relievers (e.g., codeine), psychiatric medicines, certain drowsiness-causing antihistamines (e.g., diphenhydramine). Do not start or stop any medicine without doctor or pharmacist approval.
http://www.medicinenet.com/entacapone-oral/page2.htm