Drug Interactions With Estradiol Vaginal Tablets

When certain medicines or substances are combined with estradiol vaginal tablets, drug interactions may occur. Some of the medications that could cause negative interactions include certain seizure medications, antibiotics, and barbiturates. These drug interactions with estradiol vaginal tablets may cause your body to metabolize the medications too quickly or not quickly enough, possibly leading to side effects or other problems.

An Introduction to Drug Interactions With Estradiol Vaginal Tablets

Estradiol vaginal tablets (Vagifem®) are not likely to interact with other medications, because they are taken vaginally at a low dose and little of the medication reaches the bloodstream and the liver (where many drug interactions occur).
However, because no drug-interaction studies have been done with estradiol vaginal tablets, it is possible (although not likely) that any of the usual drug interactions with estrogen medications may also occur with estradiol vaginal tablets. Some of the medicines that may lead to drug interactions with estradiol vaginal tablets include:
  • Barbiturates, such as:
    • Butalbital (Fioricet®, Fiorinal®)
    • Pentobarbital (Nembutal®)
    • Phenobarbital (Luminal®)
  • Certain antifungals or antibiotics, such as:
    • Clarithromycin (Biaxin®)
    • Erythromycin (Ery-Tab®)
    • Isoniazid (Nydrazid®)
    • Itraconazole (Sporanox®)
    • Ketoconazole (Nizoral®)
    • Miconazole
    • Telithromycin (Ketek®)
  • Rifamycin antibiotics, such as:
  • Some seizure medications, such as:
Last reviewed by: Kristi Monson, PharmD
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