Doxycycline and Cefixime Interaction
There is no significant drug interaction between doxycycline and cefixime when used together; in fact, they are often intentionally combined as complementary therapy for certain infections. 1, 2
Complementary Use in Clinical Practice
- Doxycycline and cefixime are frequently used together in treatment regimens, particularly for sexually transmitted infections, with no reported adverse drug interactions 1, 2
- The combination provides complementary coverage: cefixime targets gram-negative organisms while doxycycline provides coverage against atypical pathogens and Chlamydia 1, 3
- CDC guidelines specifically recommend combination therapy with cephalosporins (including cefixime) plus doxycycline for several conditions, indicating no concerning interaction 1
Specific Clinical Applications
- For gonorrhea treatment, cefixime 400mg oral plus doxycycline 100mg twice daily for 7 days is an alternative regimen when ceftriaxone is not available 1, 2
- For specific pathogens like Aeromonas hydrophila and Vibrio vulnificus infections, guidelines explicitly recommend doxycycline plus ceftriaxone (a similar cephalosporin to cefixime) 1, 4
- Recent clinical trials have specifically studied cefixime 800mg plus doxycycline 100mg twice daily for gonorrhea treatment, demonstrating the safety of this combination 2, 3
Efficacy Considerations
- When used together for gonorrhea-chlamydia co-infection, the combination of cefixime plus doxycycline showed a 95.3% success rate in a randomized controlled trial 3
- For treatment of certain infections, the combination may be more effective than monotherapy - studies show treatment failures with cefixime monotherapy were eliminated when combined with doxycycline 5
- The combination of cefixime and doxycycline provides excellent coverage against both Streptococcus pneumoniae and Haemophilus influenzae in respiratory infections 1
Clinical Caveats
- While there is no direct interaction between these antibiotics, both medications can cause gastrointestinal side effects, which might be additive when used together 6, 3
- When treating gonorrhea, ceftriaxone plus doxycycline showed superior efficacy compared to cefixime plus doxycycline, particularly for pharyngeal infections 2, 5
- For patients with penicillin allergies, guidelines suggest cephalosporins like cefixime should be used with caution, but doxycycline remains a safe alternative 1
Practical Considerations
- Both medications can be administered orally, improving patient compliance compared to injectable alternatives 6, 2
- Doxycycline should be taken with plenty of water and patients should remain upright for 30 minutes after taking it to prevent esophageal irritation 1
- Food does not significantly affect cefixime absorption, but may decrease the rate and extent of doxycycline absorption 6
In summary, doxycycline and cefixime do not have a clinically significant drug interaction and are frequently used together intentionally in treatment regimens for various infections.