What is the recommended usage and dosage for Birth Control (BC) patches, such as Ortho Evra (ethinyl estradiol and norelgestromin)?

Birth Control Patch Usage and Dosage Guidelines

The birth control patch (Ortho Evra/norelgestromin and ethinyl estradiol transdermal system) should be applied to the abdomen, upper torso, upper outer arm, or buttocks, using one patch for each of 3 weeks in a row, followed by 1 week off the patch, during which a withdrawal bleed usually occurs. 1

Dosage and Application

• Each patch contains 0.6 mg norelgestromin and 0.75 mg ethinyl estradiol, delivering approximately 150 mcg of norelgestromin and 20 mcg of ethinyl estradiol daily 1, 2
• Apply one new patch weekly for three consecutive weeks (21 days total)
• Week 4 is patch-free, during which withdrawal bleeding typically occurs
• Apply immediately upon removal from pouch 2
• The patch should be changed on the same day each week (the "Patch Change Day") 2

Application Sites

• Recommended application sites: abdomen, upper torso (excluding breasts), upper outer arm, or buttocks 1
• Choose a clean, dry area of skin
• Avoid areas with redness, irritation, cuts, or where clothing may rub
• Do not place on breasts or over skin that is oily, damaged, or irritated 1

Efficacy and Considerations

• Typical use failure rate is approximately 9% (similar to oral contraceptives) 1
• Perfect use failure rate is less than 1% 1
• Efficacy may be reduced in women weighing more than 198 pounds (90 kg) 1, 3
• The patch has a higher estrogen exposure (1.6 times higher) compared to low-dose oral contraceptives 1

Important Safety Considerations

• The patch carries a potential increased risk of venous thromboembolism (VTE) compared to 20-35 μg estrogen oral contraceptives, with odds ratios of 1.2 to 2.2 1
• FDA black box warning indicates increased estrogen exposure and potential increased VTE risk 1
• Due to these risks, other contraceptive methods may be safer first-line choices for patients interested in extended cycling 1
• The patch is contraindicated in women with a history of thromboembolic events or at high risk for these conditions 1

Patch Adherence and Replacement

• If a patch becomes partially or completely detached for less than 24 hours, try to reapply it or apply a new patch immediately (same Patch Change Day)
• If detached for more than 24 hours or if unsure when it detached, start a new cycle immediately and use backup contraception for the first 7 days
• Less than 2% of patches completely detach during normal use 4, 5
• Physical exercise, water immersion, and humid climates do not significantly affect patch adhesion 5

Extended Use Considerations

• While the standard regimen is 3 weeks on/1 week off, continuous use for up to 12 weeks has been studied
• During continuous use, ethinyl estradiol levels may accumulate at a rate of approximately 2.15 pg/mL per week 6
• Extended use beyond 12 weeks is not recommended without additional safety data 6

Common Side Effects

• Application site reactions (1.9%)
• Nausea (1.8%)
• Emotional lability (1.5%)
• Headache (1.1%)
• Breast discomfort (1.0%)
• Breakthrough bleeding or spotting 4

The birth control patch offers a weekly alternative to daily oral contraceptives with comparable efficacy, but users should be aware of the potentially higher estrogen exposure and VTE risk compared to some oral contraceptives. For patients who struggle with daily pill adherence, the weekly application schedule may improve compliance, with studies showing perfect compliance in approximately 90% of cycles 4.