Is it contraindicated to take Bactrim (trimethoprim/sulfamethoxazole) and Plaquenil (hydroxychloroquine) together?

Bactrim and Plaquenil Interaction: Safety Assessment

Co-administration of Bactrim (trimethoprim/sulfamethoxazole) and Plaquenil (hydroxychloroquine) is not contraindicated, but requires monitoring due to potential additive adverse effects.

Key Considerations

• No direct contraindication exists between Bactrim and Plaquenil in current guidelines 1, 2
• Both medications can be used together with appropriate monitoring and precautions 1, 2
• The primary concern is not a direct drug-drug interaction but rather potential additive adverse effects 1

Potential Concerns When Using These Medications Together

Hepatotoxicity Risk

• Trimethoprim/sulfamethoxazole can be used safely in patients with hepatitis B or C, suggesting its hepatic safety profile is acceptable 1
• Methotrexate guidelines note potential hepatotoxicity with trimethoprim but don't specifically mention hydroxychloroquine interactions 1

Hematologic Considerations

• Trimethoprim can cause folate deficiency, which may theoretically compound with hydroxychloroquine's effects 1
• Monitor for signs of bone marrow suppression, especially in elderly patients or those with renal impairment 1, 2

Dermatologic Reactions

• Both medications can cause severe dermatologic reactions including Stevens-Johnson syndrome 2
• Monitor for any new rashes or skin changes when using these medications together 1, 2

Special Populations Requiring Extra Caution

Elderly Patients

• The American Geriatrics Society identifies trimethoprim-sulfamethoxazole as requiring caution in older adults 2
• Consider more frequent monitoring in elderly patients taking both medications 1, 2

Patients with Renal Impairment

• Trimethoprim-sulfamethoxazole elimination is primarily renal, making interactions more significant in patients with reduced renal function 1
• Dose adjustments may be needed based on renal function 1

Monitoring Recommendations

• Baseline and periodic complete blood counts to monitor for hematologic effects 1, 2
• Liver function tests to assess for hepatotoxicity 1
• Electrolyte monitoring, particularly in patients also taking ACE inhibitors or ARBs 2
• Clinical assessment for skin reactions or other adverse effects 1, 2

Clinical Approach

1. Assess the necessity of both medications and consider alternatives if appropriate 1
2. Evaluate baseline renal function, hepatic function, and complete blood count 1, 2
3. Use standard dosing unless renal impairment requires adjustment 1
4. Monitor more frequently in high-risk patients (elderly, renal impairment) 1, 2
5. Educate patient about potential side effects to report (rash, unusual bleeding/bruising, yellowing of skin/eyes) 1, 2

While there is no absolute contraindication to using these medications together, the benefits should outweigh the potential risks of additive adverse effects, particularly in vulnerable populations 1, 2.