What should a patient with uncomplicated Chlamydia do if they miss a dose of doxycycline (antibiotic) while being treated with 100 mg orally twice daily for 7 days?

Missed Dose of Doxycycline for Uncomplicated Chlamydia

If a patient misses a dose of doxycycline while treating uncomplicated chlamydia, they should take the missed dose as soon as they remember, then continue the remaining doses to complete the full 7-day course, ensuring they take all 14 pills total. 1

Immediate Action for Missed Dose

• Take the missed dose immediately upon remembering, regardless of timing. 1
• Resume the regular twice-daily schedule (every 12 hours) after taking the missed dose. 1
• Do not double up doses—if it's nearly time for the next scheduled dose, skip the missed one and continue with the regular schedule. 1
• The critical goal is completing all 14 pills over 7 days to achieve the 97-98% cure rate. 2, 3

Why Completing the Full Course Matters

• Skipping doses or not completing the full 7-day course decreases treatment effectiveness and increases the likelihood that bacteria will develop resistance. 1
• Doxycycline achieves therapeutic antibacterial serum activity for 24 hours following each dose, but consistent dosing throughout 7 days is required for microbiological cure. 1
• The FDA label explicitly warns that exceeding recommended dosage may increase side effects, but it does not provide specific guidance on extending treatment duration beyond 7 days for missed doses. 1

When to Consider Alternative Management

• If the patient has missed multiple doses or cannot reliably complete the 7-day regimen, contact the provider immediately to discuss switching to single-dose azithromycin 1 g. 2, 3, 4
• Azithromycin should always be available for patients when compliance is questionable, as it provides single-dose, directly observed therapy with equivalent 97% efficacy. 2, 3
• Recent data show that only 77-85% of patients report adherence to the 7-day doxycycline regimen in real-world settings, with younger age and female sex associated with higher nonadherence rates. 5

Sexual Activity Restrictions During Treatment

• The patient must continue abstaining from all sexual intercourse until completing the full 7-day regimen AND until all sex partners are treated. 2, 3, 4
• Missing doses does not reset this timeline—the 7-day abstinence period begins from the first dose and extends through completion of all 14 pills. 2, 3
• Failing to treat sex partners leads to reinfection in up to 20% of cases. 3

Common Pitfalls to Avoid

• Do not restart the 7-day course from day one after missing a single dose—this wastes medication and delays cure. 1
• Do not assume the patient can "make up" missed doses by taking extra pills on subsequent days beyond the twice-daily regimen, as this increases side effects without improving efficacy. 1
• Do not advise the patient to stop treatment early if symptoms resolve, as asymptomatic infection is common and incomplete treatment leads to treatment failure. 2
• Take doxycycline with adequate fluids and consider taking with food or milk if gastric irritation occurs, as this reduces esophageal irritation risk without significantly affecting absorption. 1

When to Seek Medical Advice

• If the patient has missed more than 2 consecutive doses, contact the provider to discuss whether to continue doxycycline or switch to azithromycin. 2, 3
• If gastrointestinal side effects (nausea, vomiting, diarrhea) are causing nonadherence, the provider should consider switching to azithromycin, as these are the most common reasons for doxycycline nonadherence. 5
• If the patient develops severe watery or bloody diarrhea during or after treatment, contact the provider immediately, as this may indicate antibiotic-associated colitis. 1