Exemis Exemestane Phenobarbital
ModeratePhenobarbital is one of the medicines that induce CYP 3A4, and the leaflet lists it as a co-medication to be aware of when taking exemestane. The text given does not say what the effect on exemestane is or what to do about it, only that the two interact.
These medicines are often taken together with some care. Your doctor may change a dose, space them apart or check on you more often. Make sure your doctor and pharmacist know you take both.