Wyeth-Ayerst is writing to health professionals to advise them to discontinue insertion of NorplantŪ System (levonorgestrel implants) from kits with a package expiration date that includes the year 2004 (lot numbers #3990729, #3990775, #3990776, #3993006, #3003127, #3003166, #3003544 and #3003355). These lots were distributed beginning October 7, 1999.

During regular quality assurance monitoring, representative samples of the above product lots tested within product specifications, but at the lower end of the release rate specification for shelf life stability. While the test in question is designed to evaluate only shelf life stability, Wyeth-Ayerst is asking professionals to retain packages of the Norplant System with the 2004 expiration date but not to insert the implant into patients during this period of additional testing. We recommend taking this precaution while Wyeth further evaluates the shelf life stability of these lots of Norplant and any potential clinical relevance of these findings.

Product shipped before October 7, 1999 has an expiration date of 2002 and has consistently tested within specifications. Therefore, there is no reason for concern about kits shipped before October 7, 1999. This notification refers only to product from the lots referenced above.

The product label describes a five-year cumulative pregnancy rate of 3.9 percent. While, at this time, Wyeth-Ayerst does not believe that there is an incremental risk of pregnancy with these lots, during this period of additional testing, for patients in whom the avoidance of pregnancy is of great importance, use of a concurrent nonhormonal (barrier) method can be considered. If the lot number used in a specific patient is not known, patients who had their Norplant System inserted after October 7, 1999 may need to be advised regarding this issue.

The additional testing and analysis should be completed in approximately one to two months and the company should be able to provide additional information at that time.

Wyeth-Ayerst is working with the U.S. Food and Drug Administration, physicians and scientists to review available data.

In the meantime, all shipments of the Norplant System have been suspended.

Wyeth-Ayerst is undertaking a complete evaluation of this situation. If you have further questions, contact Wyeth-Ayerst Global Product Information at 1-800-934-5556.