Contraceptive patches

If the woman has adhered to the prescribed regimen and misses 1 period, she should continue using her contraceptive patches. 

Creasy GW, Fisher AC, Hall N, Shangold GA. Transdermal contraceptive patch delivering norelgestromin and ethinyl estradiol effects on the lipid profile. J Reprod Med... 

EE and most progestogens undergo extensive first-pass metabolism in the liver and gut wall, reducing their oral bioavailability. To avoid first-pass metabolism progestogens and EE can be absorbed transdermally via the combined contraceptive patch. Some hormones are metabolised... 

As the LNG-IUD has a local contraceptive action progestogenic interactions are less likely to occur. The efficacy of the contraceptive patch may be reduced by enzyme-inducing drugs [3, 11, 19]. 

Abrams, L.S. Skee, D.M. Natarajan, J. Wong, F.A. Leese, P.T. Creasy, G.W. Shangold, M.M. Pharmacokinetics of norelgestromin and ethinH estradiol delivered by a contraceptive patch (Ortho Evra /Evra) under conditions of heat humidity, and exercise. J. Clin. Pharmacol. 2001, 41, 1301-1309. 

Norelgestromin. USP. Norelgestromin, (17Ortho-Evra). First-pass metaboli.sm in the liver is avoided by the transdermal application. Hepatic metabolism does occur, however, and norgestrel. an active tnetabolite, and other hydroxylated and conjugated metabolites are formed. 

Transdermal Contraceptives. In 2001. the FDrug Administration (FDA) approved the first transdermal contraceptive patch. Onho-Evra. The product contains norel-gestnrmin and ethinyl estradiol. A patch is applied once a week for. 1 weeks, followed by a week with no patch. The pregnancy rate for this product is I in 100. a rale similar to that often observed with oral eonlraceplives. 

Contraceptive patches should be applied to the buttocks, abdomen, upper outer arm or upper torso NOT on the breasts. 

Anonymous. Ortho evra A contraceptive patch. Med Lett Drugs Ther 2002 44 8. 

Sicat BL. Ortho evra, a new contraceptive patch. Pharmacotherapy 2003 23 472 80. 

The manufacturer also points out that combined oral contraceptives (and presumably the combined hormonal contraceptive patch) must not be taken with co-cyprindiol. To do this would be analogous to doubling the ethinylestradiol dose with consequent increased risk of adverse effects. In addition, some of the progestagens in combined oral contraceptives have weak androgenic effects, which could oppose the benefits of cyproterone. 

On the other hand, the personal and ethical consequences of an unwanted pregnancy can be very serious. For this reason, the Faculty of Family Planning and Reproductive Health Care (FFPRHC) Clinical Effectiveness Unit recommends that women taking combined hormonal contraceptives should routinely use a second form of contraception, such as condoms, while taking a short course of less than 3 weeks of an antibacterial, and for 7 days after the antibacterial has been stopped. In addition, the FFPRHC recommends that if fewer than 7 active pills are left in the pack after the antibacterial has been stopped, the new packet should be started without a pill-free break, omitting any of the inactive tablets. For patients using the combined contraceptive patch, if the 7 days after the antibacterial has been stopped runs into the usual 7 day patch-free period, a new patch should be applied when it is due to be changed and the patch-free week delayed by 7 days. ... 

Abrams LS, Skee D, Natarajan J, Hutman W, Wong F. Tetracycline HCI does not affect the pharmacokinetics of a contraceptive patch. IntJ Gynaecol Obstet (2000) 70,57-8. 

The FFPRHC advise that additional contraceptive protection is not required in established users of the combined hormonal contraceptive patch taking tetracycline. This is in line with the findings of the study cited above. 

The combined contraceptive patch may be continued in the usual manner. Using more than one patch is not recommended. Additional, non-hormonal methods of contraception, such as condoms, should also be used by patients using the combined contraceptive pateh, both when taking the liver enzyme indueers and for at least 4 weeks after stopping the drug. 

---