Check Norplant stock, company says: Recent batches might be ineffective
Check Norplant stock, company says: Recent batches might be ineffective
8 product lots in question: Company to report on test findings
Check your stock of Norplant implants. The manufacturer has recommended that providers discontinue insertion of Norplant from kits that were distributed beginning Oct. 7, 1999, until further testing can settle questions about their effectiveness.
Batches affected by the advisory are from kits with a year 2004 package expiration date. The lot numbers are 3990729, 3990775, 3990776, 3993006, 3003127, 3003166, 3003544, and 3003355. Manufacturer Wyeth-Ayerst Pharmaceuticals of Philadelphia estimates about 22,000 kits are affected by the suspension; it is unsure how many of them have been inserted.
Wyeth-Ayerst mailed letters dated Aug. 10, 2000, to more than 9,000 Norplant providers and wholesalers that warned of possible problems with those particular product lots. The company initiated the mailing after routine quality-control testing revealed that one lot reported a lower-than-expected release rate result for shelf life stability.
"Due to the unique nature of the Norplant insertion procedure, Wyeth-Ayerst has taken the extra precaution of recommending that physicians not insert Norplant from seven additional lots, which were made at the same time as the one in question," states an official company release.1
Wyeth-Ayerst officials say they don’t believe there is an incremental risk of pregnancy with those lots. However, company officials are advising health care providers that during the testing period, they can consider use of a concurrent nonhormonal (barrier) method for patients in whom the avoidance of pregnancy is of great importance, says company spokeswoman Audrey Ashby.
Testing and analysis should be completed in one or two months, according to the company’s Aug. 10 provider letter.2 The company is working with the Food and Drug Administration (FDA), physicians, and scientists to review available data, and officials will contact providers when the analysis is complete, Ashby reports. (See future issues of Contraceptive Technology Update for news on the test results.) In the meantime, all shipments of the Norplant kits have been suspended.
Norplant kits shipped before Oct. 7, 1999, have an expiration date of 2002 and have tested consistently within specifications, according to the company. Those kits can be used for new insertions.
The company’s press statement suggests that women who began using Norplant after Oct. 7, 1999, should consult the health care provider who inserted the system if they have any questions and may contact Wyeth-Ayerst’s Global Product Information at (800) 934-5556.1
Providers also may call the information line if they have further questions about the product, says Ashby.
Until results are available regarding the product lots in question, what should providers do? Keep these four key points in mind, recommends Robert Hatcher, MD, MPH, professor of gynecology and obstetrics at Emory University School of Medicine in Atlanta and chairman of the CTU editorial advisory board.
1. None of the information provided about the voluntary suspension by Wyeth-Ayerst suggests that any of the implants in question are dangerous.
2. While the issue has been raised as to whether implant lots sent out after Oct. 7, 1999, retain their effectiveness, there are no data showing that they are less effective.
3. Remember that the serum level of levonorgestrel is highest following implant insertion. This fact suggests that it makes sense to wait until the test results on the lots in question are made available before making any permanent change in current-use methods, Hatcher says. Women who have the recently shipped implants are protected by the fact that little time has passed since their implants were inserted, he explains.
4. Because the whole question is one of effectiveness, to alleviate any concerns, use backup contraceptives until more information is available.
Andrew Kaunitz, MD, professor and assistant chair in the obstetrics and gynecology department at the University of Florida Health Science Center/Jacksonville, says, "If a given Norplant user has implants from the affected lots and is otherwise an appropriate candidate for DMPA [Depo Provera, or depot medroxyprogesterone acetate] injections or combination oral contraceptives, I would have no hesitation in adding’ either of these methods.
"Keep in mind, however, that Norplant users who also take [oral contraceptives] may not experience cyclical withdrawal bleeding, due to sustained continuous blood levels of levonorgestrel from the implants," he says. Kaunitz also is director of menopause and gynecology services at the Medicus Women’s Diagnostic Center in Jacksonville.
Norplant entered the U.S. market in 1991 following its approval from the FDA. Each set of Norplant implants contains 36 mg of levonorgestrel, which is released at a low, steady rate of 85 mcg daily initially and decreases to 50 mcg at nine months, 35 mcg at 18 months, and 30 mcg per day thereafter.3 The method can be reversed at any time by removing the set of six capsules.
Norplant is an extremely effective contraceptive, with a perfect-use probability of pregnancy of 0.05%.3 Because there is no scope for user error, the typical-use and perfect-use estimates are the same.3 It represents an excellent contraceptive for women who have difficulty remembering to take a daily pill or use a birth control method at the time of intercourse.3
Less than 2% use Norplant
Despite its advantages, though, U.S. use of the implant lags behind other contraceptive methods, according to a just-published study.4 Fewer than 2% of American women who were at risk of an unintended pregnancy in 1995 were using the implant, according to the analysis of two rounds of a national survey conducted in 1991 and 1993. Women gave three major reasons for not using the method: lack of knowledge, fear of side effects or health hazards, and satisfaction with their current method.4
CTU readers confirm the low levels of Norplant use. More than 70% of those responding to the 2000 Contraception Survey said they had not performed any Norplant insertions in the last year, comparable to 1999 statistics. (See the September 2000 CTU for complete results from the reader survey.) The number of Norplant removals also remained consistent with 1999 figures: About 72% reported no removals, compared to 69.3% in 1999.
References
1. Wyeth-Ayerst Pharmaceuticals. Wyeth-Ayerst Comments on Norplant System. Philadelphia: Aug. 17, 2000.
2. Wyeth-Ayerst Pharmaceuticals. "Dear Norplant Provider" correspondence. Philadelphia: Aug. 10, 2000.
3. Hatcher RA, Trussell J, Stewart F, et al. Contraceptive Technology. 17th ed. New York City: Ardent Media; 1998.
4. Tanfer K, Wierzbicki S, Payn B. Why are U.S. women not using long-acting contraceptives? Fam Plann Perspect 2000; 32:176-183, 191.
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