Contraceptive patch

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Contraceptive patch
Ortho Evra brand of contraceptive patch
Background
B.C. type Hormonal (combined estrogen + progestin)
First use  ?
Failure rates (per year)
Perfect use ≈1%
Typical use ≈1-2%
Usage
User reminders Weekly application for 3 weeks
Clinic review 3-6 monthly
Advantages
Periods Regulated, may be lighter and less painful
Benefits Compared to oral pills, may be less affected by antibiotics
Disadvantages
STD protection No
Weight gain Yes
Risks DVTs rates similar to oral combined pills

A contraceptive patch is a transdermal patch applied to the skin that releases synthetic estrogen and progestin hormones to prevent pregnancy. They are thought to have the same effectiveness as the combined oral contraceptive pill. Currently the only publicly available contraceptive patch is marketed under the brand name Ortho Evra. Contraceptive patches are often referred to by the slang term "the patch".

Contents

[edit] Method of use

In the United States and Canada, Ortho Evra is available only by prescription and is sold in boxes of three patches. Johnson & Johnson is the largest manufacturer of these patches.

A woman applies her first patch onto her upper outer arm, buttocks, abdomen or thigh on either the first day of her menstrual cycle (day 1) or on the first Sunday following that day, whichever she prefers. The day of application is known from that point as patch change day. Seven days later, when patch change day comes again, the woman removes the patch and applies another to one of the approved locations on the body. This process is repeated again on the next patch change day. On the following patch change day, the patch is removed and not replaced. The woman waits 7 days without a patch in place, and on the next patch change day she applies a new patch.

[edit] Backup contraception

  • If a woman chooses to begin with her patch change day as day 1 of her 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 a woman 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 1 start above, and no backup contraception is required.
  • If a woman chooses to begin with her 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.

[edit] Mechanism of action

Contraceptive patches are synthetic hormone contraceptives, similar in action to the combined oral contraceptive pill. The contraceptive patch product Ortho Evra contains 0.75 mg ethinylestradiol and 6.0 mg norelgestromin hormones in a single patch. The gradual release of hormones over the course of each week (approximately 20 µg/day ethinylestradiol and 150 µg/day norelgestromin) act much like contraceptive pills do. Most commonly ovulation is inhibited entirely, preventing pregnancy. Less often the cervical mucus is thickened, making it more difficult for sperm to cross through the cervix and for fertilization to occur. When both of these mechanisms fail (meaning that ovulation occurs and sperms successfully pass through increased mucus), fertilization may result. As with other hormonal contraceptives, a third mechanism by which the patch may prevent the implantation of a zygote onto the endometrium lining of the uterus is by thinning the endometrium lining.

[edit] Interactions and Contraindications

Contraceptive effectiveness of the patch or any other hormonal contraceptive may be reduced significantly if co-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 pharamacokinetic drug interaction study showed that oral administration of tetracycline HCl 500 mg for 3 days prior to and 7 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. John's Wort are also known to affect the effectiveness of hormonal contraceptives. Since the FDA only receives reports for between 1% and 10% of the serious adverse drug events, the actual death and injury rate for women on the patch is estimated to be much higher than the number of reports registered so far with the FDA

[edit] Side effects

Side effects of the patch are very similar to other synthetic hormone contraceptives such as the pill. When starting to use the contraceptive patch some people may experience slight weight gain, although this depends entirely on the individual and some people experience no weight gain at all while people who are already obese or overweight may continue to gain weight. Some people also notice changes in the intensity of sexual desire, vaginal discharge and menstrual flow. Some other common side effects are: nausea; headaches; depression; vaginitis; urinary tract infection; breast changes such as tenderness, enlargement, secretion; skin problems; and gum inflammation.

[edit] Thromboembolic risks

All forms of hormonal birth control carry some increased risk of serious or fatal thromboembolic events. Currently, 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 two-fold increased risk for non-fatal venous thromboembolic events compared with women who took a norgestimate-containing oral contraceptive with 35 micrograms of estrogen. [1]PMID 17267834 However, a different study published in the Journal of Contraception (and sponsored in part by the manufacturer of Ortho-Evra) concludes that the risk of nonfatal venous thromboembolism for the contraceptive patch is similar to the risk for oral contraceptives containing 35 micrograms of ethinylestradiol and norgestimate (PDF file). The contradictory findings between the two studies is not easily resolved, because the confidence intervals for the studies are overlapping.

In 2004, the Associated Press reported that fatal adverse events were reported to the FDA for users of Ortho-Evra at three times the rate of fatal events in oral contraceptive users. [2]. However, these comparisons do not represent methodical scientific studies. The AP noted that, "Dr. Philip Darney, a professor of obstetrics and gynecology at the University of California, San Francisco, and a leading contraceptive researcher, cautioned that the FDA’s adverse event reports tend to be inflated for newer products like the patch."

In studies with oral contraceptives, the risk for cardiovascular disease (such as thromboembolism) is substantially increased in women over the age of 35 years who also smoke tobacco (PMID 10818409). Hence, Ortho-Evra's package insert states that "Women who use hormonal contraceptives, including ORTHO EVRA®, should be strongly advised not to smoke". According to the manufacturer, the patches introduce a 60 percent higher level of estrogen into the bloodstream as compared to oral contraceptives; however, the clinical significance of this difference is unknown.

On November 10, 2005, Ortho McNeil, in conjunction with the FDA, issued a warning about the increased risks of blood clots associated with Ortho Evra Patch.

[edit] Lawsuits

The Patch has been associated with strokes and thrombosis as the mechanism for hormone absorption and dissipation from the body's tissues is different from "the pill". Several Lawsuits have been instigated over these issues.

In the new warning, Ortho McNeil admits for the first time that women who use the patch are exposed to up to 60% more estrogen than they would be exposed to if they were taking a birth control pill with 35 micrograms of estrogen. It is widely understood that any increase in the exposure to estrogen also increases the risk of blood clots.

A lawsuit filed in Federal Court in New Jersey on September 2, 2005, by a Georgia woman, who suffered a pulmonary embolism, alleges the company promoted the patch despite knowledge of its health risks, for financial gain while failing to warn of the risks of blood clots and other injuries.

Around the time the company introduced the patch to the market, the lawsuit claims, Ortho's patent for its contraceptive pill, Ortho Tri-Cyclen, was about to expire, creating pressure to make up for lost revenue.

In November 2005, CBS News aired a story about documents that surfaced in a lawsuit involving a young mother who was paralyzed by a stroke and remained a total invalid, that showed the company had received nearly 500 reports of adverse events between April 2002 and December 2004. During the same time frame, only 61 adverse event reports were filed in connection with all type of birth control pills. [3]

The parents of a 14 year-old girl from Wisconsin have filed a lawsuit against Johnson & Johnson because they claim that she died from a blood clot that arose from her use of the patch.[4]

[edit] References

[edit] External links


Birth control edit
Sterilization: Tubal ligation, Vasectomy, Essure
Post-intercourse: Abortion: Surgical, Medical
Emergency contraception
Intra-uterine: IUD, IUS (progestogen)
Anti-estrogen: Ormeloxifene (a.k.a. Centchroman)
Hormonal: Combined: COCP ('the Pill'), Patch, Nuvaring
Progestogen only: POP mini-pill, Depo Provera, Norplant, Implanon
Barrier: Male condom, Female condom, Diaphragm, Shield, Cap, Sponge, Spermicide
Behavioral: Coitus interruptus, Rhythm Method, Lactational, Fertility awareness
Avoiding vaginal intercourse: Anal sex, Oral sex, Outercourse, Masturbation, Abstinence
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