Oral doxycycline for treatment of neurosyphilis in two patients infected with human immunodeficiency virus

Abstract

The frequency of syphilis has been increasing during the past 5 years primarily among men who have sex with men, many of whom are infected with the human immunodeficiency virus (HIV). Data on treatment options other than intravenous or intramuscular penicillin for syphilis are very limited. We describe two HIV-infected patients with asymptomatic neurosyphilis who were successfully treated with oral doxycycline. The first patient was a 45-year-old Hispanic man with well-suppressed HIV RNA who had a positive Venereal Disease Research Laboratory (VDRL) titer of 1:128. His cerebral spinal fluid (CSF) revealed a positive VDRL titer of 1:16, and an elevated white blood cell count of 96 cells/mm(3) and protein level of 89 mg/dl. He received high-dose doxycycline 200 mg twice/day for 28 days. Two months later, his CSF VDRL titer, white blood cell count, and protein level decreased to 1:4, 5 cells/mm(3), and 60 mg/dl, respectively. The second patient was a 37-year-old Caucasian man with complications from acquired immunodeficiency disease. A routine VDRL titer was found to be 1:64. Although the CSF VDRL was nonreactive, both his white blood cell count and protein level were elevated at 29 cells/mm(3) and 46 mg/dl, respectively. High-dose doxycycline 200 mg twice/day was prescribed for 28 days. Three months later, the patient's VDRL titer decreased to 1:2; his CSF white blood cell count decreased significantly to 1 cell/mm(3), and his protein level was within normal limits. Clinicians should be aware that an extended course of high-dose, oral doxycycline may be an effective and safe alternative regimen to intravenous or intramuscular penicillin, without requiring hospitalization or home health care, for the treatment of neurosyphilis in HIV-infected patients. Prospective trials are needed to assess the long-term efficacy oral doxycycline for neurosyphilis.