Oral Doxycycline Shows Promise in Ocular Syphilis Care

TOPLINE:

Oral doxycycline (200 mg twice daily for 28 days) appears to be as effective as intravenous (IV) penicillin for the treatment of ocular syphilis for some patients with the condition.

METHODOLOGY:

• Researchers conducted a retrospective cohort study of ocular syphilis cases diagnosed from 2017 to 2023 in Los Angeles, analyzing 32 patients with a median age of 46 years (78% men).
• Patients treated before January 2022 received IV doxycycline, while those treated after that date were given the option to receive an oral form of the drug.
• A total of 16 patients received oral doxycycline (seven patients received only oral doxycycline; nine received a short course of parenteral penicillin followed by a full course of oral doxycycline); another 16 patients received a full course of IV penicillin.
• The analysis measured visual acuity (VA), ocular inflammation, and rapid plasma reagin (RPR).

TAKEAWAY:

• The doxycycline group had better median VA at both the initial presentation and the final follow-up than the penicillin group (VA, 0.44, 0.18; P = .04; VA, 1.0, 0.40; P = .03, respectively).
• Resolution of ocular inflammation showed no significant differences between the doxycycline and IV penicillin groups (P = .62 for both).
• All patients who had follow-up at 9 months demonstrated a fourfold decrease in RPR titers (four people in the oral doxycycline group and seven people in the IV penicillin group).

IN PRACTICE:

“We found that oral doxycycline for the treatment of ocular syphilis may be safe and effective in a selected subset of patients who completed an extended oral antibiotic regimen,” the study authors wrote. “Other studies have also demonstrated similar efficacy of oral therapy when compared with IV therapy. A fourfold decrease in RPR titers was considered an adequate serologic treatment response and corresponds with resolution of syphilis disease activity. This was observed in all patients with more than 9 months of follow-up. Long-term monitoring is recommended for those treated with doxycycline to ensure clinical and serologic response.”

SOURCE:

The study was led by Brian C. Toy, MD, of the Roski Eye Institute at the Keck School of Medicine at the University of Southern California in Los Angeles. It was published online on December 6, 2024, in JAMA Network Open.

LIMITATIONS:

The study was retrospective in nature, used heterogeneous treatment methods, and lacked longitudinal RPR titers.

DISCLOSURES:

Toy served on physician advisory boards for Alimera, EyePoint, Bausch and Lomb, and Regeneron. No other disclosures were reported.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.