What are the first-line treatment options for uncomplicated Chlamydia infections in adults?

First-line treatment options for uncomplicated Chlamydia infections in adult patients (non-pregnant) are:

• Doxycycline 100 mg orally twice daily for 7 days.
• If doxycycline is contraindicated or not tolerated, consider azithromycin: 1 g orally as a single dose on day 1, followed by 500 mg orally once daily for 2 days.
• If both doxycycline and azithromycin are contraindicated, erythromycin 500 mg twice daily for 10–14 days is an alternative.

Systemic fluoroquinolones such as ofloxacin are possible alternatives but are reserved for cases where first-line antibiotics are contraindicated or ineffective due to their risk of serious side effects and are contraindicated in pregnancy and children.

For pregnant women, treatment options include azithromycin, erythromycin, or amoxicillin, with specialist advice recommended.

Patients should be advised that sexual partners must also be treated to prevent reinfection, and sexual intercourse should be avoided until treatment is completed and effective.

Referral to a genito-urinary medicine (GUM) clinic is strongly recommended if possible.

All treatment recommendations are based on the BASHH national guideline and UK clinical guidance.

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