Patch, vaginal ring offer steady hormone levels

OB/GYN News,  Feb 15, 2002  by Elizabeth Mechcatie

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WASHINGTON -- A constant, nonfluctuating hormone serum level and ease of use are among the positive attributes of the recently approved contraceptive vaginal ring and contraceptive patch, Dr. Felicia Stewart said at the annual meeting of the Association of Reproductive Health Professionals.

The disposable vaginal ring, marketed as the NuvaRing by Organon Inc., is inserted intravaginally and releases etonogestrel and ethinyl estradiol over 3 weeks and is then removed. A week later another ring is inserted.

To begin ring use, a woman inserts her first ring in the first 5 days after starting a menstrual period. The schedule is then 3 weeks of ring use and 1 week without. The ring, which measures about 2.1 inches in diameter, releases 15 [micro]g of ethinyl estradiol and 120 [micro]g of etonogestrel daily, a pattern similar to that of oral contraceptives but the ring maintains steadier serum levels, said Dr. Stewart, director of the Center for Reproductive Health Research and Policy at the University of California, San Francisco.

Like the contraceptive ring, the contraceptive patch achieves peak hormone serum levels gradually Hormones are embedded in the adhesive layer of the patch, marketed as Ortho Evra by Ortho-McNeil Pharmaceutical Inc. The patch, which is 4.5 cm square, releases 20 [micro]g of ethinyl estradiol and 150 [micro]g of norelgestromin daily and is applied to the lower abdomen, buttocks, or upper body for 3 weeks, followed by one patch-free week.

In January, Organon made the NuvaRing available to about 5,000 physicians and plans to launch the device nationwide in June. The contraceptive patch will be launched during the first half of this year, according to Ortho-McNeil. Dr. Stewart receives research support from Ortho-McNeil and has received grant support from Organon.

Dr. Stewart noted that the NuvaRing is easy for women to insert and that hormone absorption is not affected by the device's exact position in the vagina. Once the method is discontinued, ovulation returns rapidly.

The rate of absorption with NuvaRing is more gradual than with OCs, she noted. The maximum concentration of etonogestrel is reached 200 hours after insertion and the maximum concentration of ethinyl estradiol is reached 59 hours after insertion, compared with 1.3 and 1.2 hours, respectively, with OCs, she said.

In a 1-year European efficacy study, the number of pregnancies overall was 6 per 12,109 cycles, for a rate of 0.65%. Of the six pregnancies, three occurred with perfect use. In a U.S. study, the pregnancy rat was slightly greater, with 15 pregnancies occurring in 11,189 cycles, for a rate of 1.75%, with 7 of the pregnancies occur ring with perfect use.

Although removal is not recommended a woman can remove the ring temporarily for intercourse as long as it is reinserted within 3 hours, she said. If removal does not exceed 3 hours, no back-up contraceptive is advised, Dr. Stewart said.

Side effects related to the ring are similar to those associated with OCs and include headache and nausea. Side effects specific to the device included a foreign body sensation, leukorrhea, vaginitis, and device expulsion. In trials, about 8% of women said they could feel the ring.

The method was discontinued because of problems by 15% of users; reasons included discomfort, expulsion, interference with sex, headache, nausea, and bleeding irregularity.

In the one published study comparing the patch to a combination OC (Triphasil) in 1,417 women in the United States and Canada, the patch was comparable to combination OCs with regard to efficacy and cycle control, and compliance was better (JAMA 285[18]:2347-54, 2001).

In the study, there were 5 pregnancies per 5,240 cycles for a rate of 1.2 pregnancies per 100 women years, compared with 7 pregnancies per 4,167 cycles of pill use, for a rate of 2.18 pregnancies per 100 women years, an insignificant difference.

There were four pregnancies in each group with perfect use. The patch was used with "perfect compliance" in 88% of cycles vs. 78% of cycles with the OC, a significant difference.

Overall, bleeding was comparable but higher with the patch in the first two cycles.

The most common adverse effects were similar in OC and patch users, except for breast tenderness, reported by 19% of those on the patch and 6% of those on OCs during the first cycle, but the rate decreased steadily in subsequent cycles.

Over 1 year, the buttocks were the most common site the patch was placed by patients, followed by the abdomen, arm, and torso. Complete detachment occurred in 1.8% of applications and partial detachment in nearly 3%. Application site reactions occurred in 3% of contraceptive patch users.

COPYRIGHT 2002 International Medical News Group
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