Can You Take Bactrim and Doxycycline Together?
Yes, Bactrim (trimethoprim-sulfamethoxazole) and doxycycline can be taken together for an eyebrow-piercing infection in patients over 8 years old without contraindications, and this combination has documented clinical use for treating resistant infections. 1
Evidence Supporting Combination Therapy
The combination of these two antibiotics has been successfully used in clinical practice:
A documented case report demonstrates effective use of trimethoprim-sulfamethoxazole combined with doxycycline for treating a resistant urinary tract infection caused by Mycobacterium fortuitum, where conventional therapy had failed. 1 This establishes precedent for combining these agents when treating difficult infections.
Both antibiotics have been studied together for prophylaxis of travelers' diarrhea, showing that concurrent use is feasible without prohibitive adverse effects. 2
Individual Agent Coverage for Skin Infections
For an eyebrow-piercing infection, both agents provide appropriate coverage:
Bactrim is recommended at 1-2 double-strength tablets twice daily for skin and soft tissue infections, typically for 7 days, with particular efficacy against MRSA (91.9% cure rate for uncomplicated wound infections). 3, 4
Doxycycline is recommended as an alternative agent for MRSA skin infections at 100 mg orally twice daily, and can be safely used in children over 8 years old for durations less than 2 weeks. 5, 4
Critical Limitation: Streptococcal Coverage Gap
The most important caveat is that Bactrim has poor activity against beta-hemolytic streptococci, so if streptococcal infection is suspected in a non-purulent cellulitis, Bactrim should not be used as monotherapy. 4, 6
For purulent infections (abscesses, furuncles) where MRSA is the primary concern, Bactrim alone or with doxycycline is appropriate. 3
For mixed infections or non-purulent cellulitis, adding a beta-lactam antibiotic (amoxicillin or cephalexin) would be necessary to cover streptococci. 4
No Documented Drug-Drug Interaction
Importantly, the available evidence does not identify any significant pharmacokinetic or pharmacodynamic interaction between Bactrim and doxycycline:
Guidelines discussing methotrexate interactions specifically mention that tetracyclines (including doxycycline) can increase methotrexate levels, but this concern relates to methotrexate, not to combining tetracyclines with Bactrim. 5
The acne treatment guidelines recommend both agents as alternatives to each other but do not contraindicate their combination. 5
Practical Dosing Approach for Eyebrow-Piercing Infection
For a purulent eyebrow-piercing infection (suggesting MRSA), use:
- Bactrim DS 1-2 tablets orally twice daily (use 2 tablets for more extensive infection) 3, 4
- Doxycycline 100 mg orally twice daily 4
- Duration: 7-10 days for simple infections, up to 14 days for complicated infections 4
If the infection appears non-purulent with surrounding cellulitis (suggesting possible streptococcal involvement), add amoxicillin 500 mg three times daily or cephalexin 500 mg four times daily to cover the streptococcal gap. 4
Contraindications to Verify
Before prescribing this combination, confirm the patient does not have:
- Sulfa allergy (contraindication to Bactrim) 3
- Third trimester pregnancy (Bactrim contraindicated due to kernicterus risk) 3, 6
- Age under 8 years (doxycycline contraindicated due to tooth staining) 5
- G6PD deficiency (Bactrim contraindicated due to hemolytic anemia risk) 6
- Significant renal impairment requiring dose adjustment 3