Health Canada Ortho Evra Patch safety update November 29th 2006:
The US FDA has changed the labelling for the Ortho Evra Patch, as up to 60% more estrogen may be absorbed than originally thought. The US patch, which has 75 micrograms of estrogen in it, has a different formulation than the Canadian patch, which has 60 micrograms of estrogen. Increased levels of estrogen may lead to adverse effects, such as increased risk of blood clots and stroke.
Essentially, we do not know how much more estrogen is absorbed with the Canadian Evra Patch. If clients are concerned, they are advised to speak with their health care professional or visit their local OPT clinic for further guidance. The Patch should not be used as a continuous method of birth control (i.e. 'back to back').
Health Canada has not sent out an advisory on this issue; the Society of Obstetricians and Gynaecologists of Canada (SOGC) has issued the following statement:
EVRA Transdermal Contraceptive Patch Update from the The Society of Obstetricians and Gynaecologists of Canada (SOGC)
EVRA marketed in Canada has lower estrogen amounts than ORTHO EVRA in the US. On November 10, 2005, the US Food and Drug Administration (FDA) announced new prescribing information for the ORTHO EVRA (norelgestromin/ethinyl estradiol transdermal system) birth control patch.
The US prescribing information has been revised to include a warning that systemic exposure (area under the curve) of ethinyl estradiol (EE) is approximately 60% higher in women using ORTHO EVRA compared with women using an oral contraceptive containing EE 35µg. In contrast, peak concentrations for EE are approximately 25% lower in women using the patch.
A recent pharmacokinetic study comparing EVRA to an oral contraceptive containing 35µg EE and 250mgs norgestimate (CYCLEN) indicated that the exposure for EE and NGMN were comparable for EVRA and CYCLEN. It should also be noted that there has been no causal link identified between the higher level of estrogen from the US manufactured ORTHO EVRA patch and any increased risk of VTE.
The new prescribing information provided in the Unites States does not apply to the Canadian market as EVRA sold in Canada uses a different manufacturing process than the patch sold in the US. ORTHO EVRA marketed in the US has 75µg EE vs. the Canadian EVRA patch which contains a lower amount of ethinyl estradiol (60µg EE), producing estrogen levels comparable to 35µg pills.
Healthcare providers and their patients can be reassured that EVRA remains a safe and effective contraceptive choice in Canada.
