Are there any interactions between Augmentin (amoxicillin/clavulanate) and Doxycycline?

Drug Interaction Between Augmentin and Doxycycline

There are no clinically significant drug interactions between Augmentin (amoxicillin/clavulanate) and doxycycline, and these antibiotics can be safely used together when clinically indicated.

Evidence for Concurrent Use

The combination of Augmentin and doxycycline has been specifically studied and used in clinical practice:

• Pelvic inflammatory disease: A clinical study demonstrated successful outpatient treatment using Augmentin with doxycycline, with 35 of 47 patients who completed therapy achieving cure or improvement 1. The combination was well-tolerated, though gastrointestinal side effects led to discontinuation in 20% of patients 1.

• Skin and soft tissue infections: Guidelines recommend combining beta-lactams (including amoxicillin/clavulanate) with doxycycline as an alternative to macrolides for patients with animal bites and certain wound infections 2.

• Community-acquired pneumonia: Clinical practice guidelines explicitly list doxycycline as an acceptable alternative to macrolides when combined with beta-lactam antibiotics for hospitalized patients 2.

Mechanism Considerations

No pharmacokinetic or pharmacodynamic antagonism exists between these agents:

• Doxycycline is a bacteriostatic tetracycline antibiotic, while Augmentin is a bactericidal beta-lactam combination 2.

• The theoretical concern about mixing bacteriostatic and bactericidal antibiotics is not clinically relevant for this combination, as evidenced by successful use in multiple clinical scenarios 2, 1.

• Neither drug significantly affects the metabolism or excretion of the other 2.

Clinical Applications Where Combination Is Used

This combination is appropriate for:

• Polymicrobial infections requiring broad-spectrum coverage including anaerobes and atypical pathogens 2
• Necrotizing fasciitis when combined with other agents 2
• Diabetic wound infections with mixed bacterial flora 2
• Respiratory infections in patients with macrolide allergy or intolerance 2

Important Caveats

Monitor for additive gastrointestinal effects:

• Both antibiotics can cause nausea and diarrhea 1, 3
• The combination may increase the risk of GI side effects, which was the most common reason for treatment discontinuation in the pelvic inflammatory disease study (20% of patients) 1

Avoid doxycycline in specific populations:

• Children under 8 years of age (risk of tooth discoloration) 2
• Pregnant women, particularly in second and third trimesters 2
• Breastfeeding mothers when infant is premature or jaundiced 2