There is currently no generic Estring approved in the United States. Although all of the patents for the medication have expired, no generic versions are expected to become available any time soon. There may be companies out there claiming to sell generic Estring; however, these products may be fake, substandard, and potentially dangerous.
Estring® (estradiol vaginal ring) is a prescription hormone replacement medication used to treat vaginal menopause symptoms, such as vaginal dryness, itching, or burning, and urinary menopause symptoms, including painful or urgent urination. Estring is a small, flexible ring that is inserted vaginally and left in place for up to 90 days.
Estring is made by Pfizer, Inc. There are currently no generic versions of the drug approved in the United States. However, if you search the Internet for "generic Estring," you may find a number of companies selling it or claiming to sell it. The fact is that these medicines may be fake, substandard, and potentially dangerous. Generic Estring may be available from another country, but there is really no way of knowing whether you are getting genuine Estring. Therefore, you should not buy any generic Estring until there is an approved generic version available.
It is not entirely clear why there are no generic versions of Estring, as there are no unexpired patents for this medication. Perhaps it may not be profitable enough for a manufacturer to make a generic version. Or, it is possible that it may be too difficult for a generic manufacturer to make a vaginal estradiol ring that is identical to Estring.
This is difficult to predict. There may never be any generic versions of Estring. At this point, generic Estring is not expected to become available in the immediate future.