November 10, 2005 - SOGC Statement

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 0.75 mg EE vs. the Canadian EVRA patch which contains a lower amount of ethinyl estradiol (0.6 mg EE), producing estrogen levels comparable to 35µg pills.