Both Estradot® and Climara® transdermal patches contain estradiol in an adhesive matrix with a release rate proportional to the surface area of the patch. E.g. the Estradot 25® patches release 25 micrograms of estradiol per day from a patch with an area of 2.5 cm2, whereas the Estradot 50® patches release 50 micrograms per day from a patch with an area of 5 cm2.
With shortages of some brands and strengths of estradiol transdermal patches, patients may not be able to obtain their usual strength of estradiol patches. For these patients, one option is to apply a smaller portion of a higher strength patch. This is best done by cutting the patch to obtain the required surface area e.g.:
- Cut an Estradot 100® patch in half to replace an Estradot 50® patch.
- Cut an Estradot 75® patch in thirds to replace an Estradot 25® patch
Advise patients to return the other portion(s) to the foil-lined protective pouch, place in a zip-lock bag and store in a cool, dry place similar to other medicines. The other portion(s) should be used for the next application(s).
PHARMAC have information on issues with estradiol patches here.
PHARMAC have funded a section 29 product: Estradiol Transdermal System Mylan® 25 and 50 microgram patches. This appears to be a generic version of Estradot® used in the United States. These patches could also be cut if required. The overseas product information can be accessed here.
Health professionals are welcome to contact our service for more specific advice on individual patients.