Levonorgestrel Implants and Intracranial Hypertension

To the Editor: Levonorgestrel (Norplant, Wyeth–Ayerst Laboratories, Philadelphia) is a subdermally implanted synthetic progestin that has been available in the United States since 1991. Intracranial hypertension developed in two women seen at the Oregon Health Sciences University after the insertion of this implant. We reviewed data from the national Registry of Drug-Induced Ocular Side Effects (Casey Eye Institute, Portland, Oreg.), the Food and Drug Administration's Spontaneous Reporting System (Rockville, Md.), and the World Health Organization's Collaborating Center for International Drug Monitoring (Uppsala, Sweden) for a possible association between levonorgestrel use and intracranial hypertension. A total of 56 cases of intracranial.