Switching to another patch

Three families of US patches

Sizes from each product's label on DailyMed; the FDA's ratings from the Orange Book.

Within a family, the FDA rates the generics as equivalent to the brand. Between families the strength is the same, but the patches are different products: a weekly patch holds a week's estradiol in a larger patch, a twice-weekly one holds 3 to 4 days' worth in a smaller one. In Canada, Estradot and Sandoz Estradiol Derm are twice-weekly and Climara is weekly.

What the labels say

• Vivelle-Dot's label says it can be started at once "in a woman switching from another estradiol transdermal therapy" (Vivelle-Dot label).
• Climara's label says to wear only one patch at a time during the 7 days (Climara label).
• If a weekly patch falls off and can't be put back, the Climara label says to put on a new one for the rest of that week; the twice-weekly labels say to carry on with the original schedule.
• None of the patch labels mentions cutting a patch. ASHP warns that cutting one "may result in uneven dose release" (ASHP).

How and when to switch is your prescriber's or pharmacist's call, especially between a weekly and a twice-weekly patch.

What doctors have told the press

Dr JoAnn Pinkerton of UVA Health, a past president of The Menopause Society, told AARP that patients can use "a different brand of a twice-a-week patch or a once-a-week patch for a short interim". Dr Lauren Streicher of Northwestern said most people given a reasonably equivalent dose "are not going to notice the difference", while some may get less estrogen and should raise it with their prescriber (AARP).

Cost when you switch

A different brand may sit on a different tier of your plan's formulary. If a shortage forces you onto one that isn't preferred, ask your prescriber about a coverage exception before you pay the difference.