Before taking Premphase, talk to your healthcare provider about other medications you are taking to avoid possible drug interactions. Premphase can cause negative interactions with many medications, such as cyclosporine, protease inhibitors, and various antibiotics. Some of these drug interactions with Premphase can affect the way your body metabolizes these medicines, possibly increasing your risk of side effects or decreasing the effectiveness of the medications.
Premphase® (conjugated estrogens/cyclic medroxyprogesterone) can potentially interact with several other medicines. Some of the medicines that may lead to Premphase drug interactions include:
Barbiturates, such as:
Amobarbital (Amytal®)
Butalbital (Fioricet®, Fiorinal®)
Pentobarbital (Nembutal®)
Phenobarbital (Luminal®)
Secobarbital (Seconal®)
Cyclosporine (Gengraf®, Neoral®, Sandimmune®)
Grapefruit juice
Hypothyroidism (underactive thyroid) medications, such as: