What are the effects of taking Trimethoprim/Sulfamethoxazole (Bactrim) and Levofloxacin (Levaquin) together?

From the Guidelines

Taking Bactrim (sulfamethoxazole-trimethoprim) and Levaquin (levofloxacin) together is generally not recommended due to overlapping side effects and no significant therapeutic advantage, unless in specific cases of high-risk infections where combination therapy may be beneficial 1. When considering the use of these antibiotics together, it's essential to weigh the potential benefits against the risks of increased toxicity and the development of multiresistant organisms.

• The European Respiratory Journal study 1 suggests that combination broad-spectrum therapy may be associated with greater toxicity and is a risk factor for the later emergence of multiresistant organisms and increased rates of superinfection.
• However, the same study also notes that in patients with septic shock or severe disease, a regimen initially combining two antibiotics targeting Gram-negative bacteria may increase the proportion of appropriately treated patients and may increase the rate of bacterial killing. Some key points to consider when evaluating the use of Bactrim and Levaquin together include:
• The potential for overlapping side effects, such as increased sun sensitivity, tendon problems, and QT interval prolongation 1.
• The lack of significant therapeutic advantage in using these antibiotics together, as both target bacterial infections and can achieve similar clinical benefits alone 1.
• The importance of considering the specific context of the infection, including the risk of mortality and the potential for multiresistant organisms 1. In general, monotherapy with a broad-spectrum antibiotic, such as levofloxacin, is recommended for patients at low risk of mortality and multiresistant organisms 1. However, in cases where combination therapy is deemed necessary, the use of a broad-spectrum β-lactam combined with an aminoglycoside or a fluoroquinolone may be considered, but should be done so with caution and careful monitoring for potential adverse effects 1.

From the Research

Combination Therapy with Bactrim and Levaquin

• The use of combination antimicrobial therapy, including the combination of Bactrim (trimethoprim-sulfamethoxazole) and Levaquin (levofloxacin), has been explored in various studies 2.
• Bactrim is a combination of trimethoprim and sulfamethoxazole, which has been shown to be effective against a wide range of bacterial infections, including urinary tract infections 3, 4, 5.
• Levaquin, on the other hand, is a fluoroquinolone antibiotic that is effective against a broad spectrum of bacterial infections, including Gram-negative and Gram-positive bacteria.
• The combination of Bactrim and Levaquin may be considered for the treatment of serious Gram-negative infections, such as those caused by Pseudomonas aeruginosa and Serratia marcescens, as well as certain Gram-positive infections caused by Enterococcus spp. and Staphylococcus spp. 2.
• However, the selection of agents should be dependent upon local susceptibility patterns, clinical experience, site of infection, potential toxicities, and cost 2.

Advantages and Disadvantages of Combination Therapy

• The advantages of combination therapy include the potential for synergistic activity, bactericidal activity, and the ability to decrease the rate of emergence of resistance to the individual components 2, 5.
• However, combination therapy also has disadvantages, including increased expense, increased risk of adverse effects, antagonism, and superinfection 2.
• The use of Bactrim and Levaquin together may increase the risk of adverse effects, such as gastrointestinal intolerance and skin eruptions, which are common adverse reactions to both drugs 4, 5.

Specific Considerations for Bactrim and Levaquin

• Bactrim has been shown to be effective in the prevention of urinary tract infections in renal transplant recipients, and is often used as a first-line agent for this indication 6.
• Levaquin, on the other hand, has been shown to be effective in the prevention of urinary tract infections in renal transplant recipients, and may be considered as an alternative to Bactrim in patients who are unable to tolerate Bactrim due to toxicity 6.
• However, the use of Levaquin has been associated with a higher incidence of pneumocystis pneumonia compared to Bactrim, and therefore may not be the preferred agent for patients at risk for this infection 6.