Additionally, avoid using lotions, powder, or makeup around the area where the patch is or will be placed. Backup contraception
If someone chooses to begin with their patch change day as day one of their menstrual cycle, the patch is able to take effect in time to prevent ovulation (see Mechanism of Action below) and no form of backup contraception is needed at all. In the case that one wishes to begin using the contraceptive patch following a first trimester abortion or miscarriage, patch application can be done immediately afterwards. This can be considered the same as a day one start above, and no backup contraception is required. If a user chooses to begin with their patch change day as the first Sunday following day 1, it is necessary to use a backup form of contraception such as spermicide or condoms for the first week of patch wear. If the user is late placing her patch in the first week, or more than two days late placing the patch in the second and third weeks, they should apply the patch immediately, and then use a backup form of barrier protection for a week. Mechanism of action
Like all combined hormonal contraceptives, Ortho Evra / Evra works primarily by preventing ovulation. A secondary mechanism of action is inhibition of sperm penetration by changes in the cervical mucus.
Interactions and contraindications
Contraceptive effectiveness of the patch or any other hormonal contraceptive may be reduced significantly if administered alongside various antibiotics, antifungals, anticonvulsants, or other drugs that increase metabolism of contraceptive steroids.However, despite the interactions with many other antibiotics, a clinical pharmacokinetic drug interaction study showed that oral administration of tetracycline HCl 500 mg for three days prior to and seven days during use of Ortho Evra "did not reduce effectiveness of Ortho Evra." This is a significant factor in the common decision to administer tetracycline-derived antibiotics following an abortion (preventatively to fight potential infection) when synthetic hormone contraceptives are to be used afterwards.Drugs containing St. Johns wort are also known to affect the effectiveness of hormonal contraceptives.It has also been found that the patch is less effective in women who weigh more than 198 pounds (90 kg). The contraceptive patch and other combination hormonal contraceptives are contraindicated in women older than 35 years who smoke cigarettes.The contraceptive patch is contraindicated for use in women with a BMI ≥ 30 kg/m2. Thromboembolism
All combined hormonal birth control products have a very small increased risk of serious or fatal thromboembolic events. There is ongoing research into the thromboembolic risks of Ortho Evra as compared to combined oral contraceptive pills. A recent study found that users of the contraceptive patch may have a twofold increased risk for non-fatal venous thromboembolic events compared with women who took a norgestimate-containing oral contraceptive with 35 µg of estrogen.