From the Guidelines
Cephalexin and Bactrim (sulfamethoxazole/trimethoprim) can be given together when clinically indicated, as there is no significant drug interaction between these two antibiotics, according to the most recent guidelines 1. This combination may be prescribed in certain situations where broader antimicrobial coverage is needed, such as for complicated skin infections or when treating infections with suspected resistant organisms.
- The guidelines suggest that cephalexin can be used for nonpurulent cellulitis, providing coverage for b-hemolytic streptococci, while Bactrim (TMP-SMX) can be used for purulent cellulitis, providing coverage for CA-MRSA 1.
- However, using both medications simultaneously increases the risk of side effects, particularly kidney problems and allergic reactions.
- Patients taking this combination should maintain adequate hydration and promptly report any unusual symptoms like rash, fever, or decreased urination.
- The combination works through complementary mechanisms - cephalexin disrupts bacterial cell wall synthesis while Bactrim blocks two sequential steps in bacterial folate synthesis.
- This dual approach can be effective against a wider range of bacteria than either antibiotic alone, but should only be used when specifically prescribed by a healthcare provider who has determined that the benefits outweigh the potential risks, as stated in the guidelines 1.
- It is essential to note that the decision to use this combination should be based on the severity of the infection, local epidemiology, and the patient's individual needs, as outlined in the guidelines 1.
From the Research
Combination Therapy of Cephalexin and Bactrim
- The combination of Cephalexin and Bactrim (sulfamethoxazole/trimethoprim) has been studied in various clinical trials to determine its effectiveness in treating different types of infections.
- A study published in 2013 2 found that the addition of trimethoprim-sulfamethoxazole to cephalexin did not improve outcomes in patients with uncomplicated cellulitis.
- Another study published in 2017 3 also found that the use of cephalexin plus trimethoprim-sulfamethoxazole did not result in higher rates of clinical resolution of cellulitis compared to cephalexin alone.
- However, it is essential to note that these studies were focused on specific types of infections, and the results may not be generalizable to other conditions.
- In terms of safety, a study published in 1977 4 reported that all side effects associated with the use of Sulprim (a combination of trimethoprim and sulphametoxazol) were reversible.
Specific Considerations
- The study published in 2023 5 compared the effectiveness of cefdinir, cephalexin, and sulfamethoxazole-trimethoprim in treating outpatient pediatric urinary tract infections and found that cephalexin had a lower rate of medication changes compared to sulfamethoxazole-trimethoprim.
- A study published in 1972 6 compared the effectiveness of ampicillin, cephalexin, co-trimoxazole, and trimethoprim in treating urinary infections and found that trimethoprim alone was at least as effective as the other compounds in treating domiciliary infections and bacteriuria in pregnancy.
- These studies suggest that the combination of cephalexin and Bactrim may be used in certain clinical scenarios, but the decision to use this combination should be based on the specific clinical context and the potential benefits and risks associated with its use 2, 3.