Can a female patient with a urinary tract infection (UTI) and elevated liver function tests be started on Bactrim (trimethoprim/sulfamethoxazole)?

From the Guidelines

I would not recommend starting Bactrim (trimethoprim-sulfamethoxazole) for this female patient with a UTI who was admitted for elevated liver function tests. Bactrim can potentially worsen liver function as it may cause hepatotoxicity, especially in patients with pre-existing liver issues. Instead, consider alternative antibiotics with less hepatic impact such as nitrofurantoin (100mg twice daily for 5-7 days) 1, fosfomycin (3g single dose) 1, or cephalexin (500mg four times daily for 7 days), depending on local resistance patterns and urine culture results. The choice should be guided by the patient's specific UTI pathogen sensitivities, renal function, and severity of liver dysfunction. Some key points to consider when choosing an antibiotic for this patient include:

• The patient's liver function tests should be monitored during antibiotic therapy regardless of which agent is chosen.
• The underlying cause of the elevated liver enzymes should also be investigated and addressed, as this may influence both UTI treatment and overall management.
• Once liver function improves, Bactrim could potentially be reconsidered if it's the most appropriate option based on culture results. According to the most recent guidelines from the American College of Physicians, nitrofurantoin for 5 days, trimethoprim–sulfamethoxazole (TMP–SMZ) for 3 days, or fosfomycin as a single dose are recommended for women with uncomplicated bacterial cystitis 1. However, given the patient's elevated liver function tests, it is crucial to select an antibiotic that minimizes the risk of hepatotoxicity. In this case, nitrofurantoin or fosfomycin may be a better option compared to Bactrim, considering their efficacy and lower risk of hepatotoxicity 1. Ultimately, the choice of antibiotic should be individualized based on the patient's specific clinical scenario, including the severity of the UTI, local resistance patterns, and the patient's overall health status.

From the FDA Drug Label

If a patient develops skin rash, fever, leukopenia or any sign of adverse reaction, re-evaluate benefit-risk of continuing therapy or re-challenge with sulfamethoxazole and trimethoprim Laboratory Tests Complete blood counts and clinical chemistry testing should be done frequently in patients receiving sulfamethoxazole and trimethoprim. The patient has high liver function test, and there is no direct information in the label that supports the use of Bactrim in this case. Key considerations:

• The label recommends frequent laboratory tests, including clinical chemistry testing, for patients receiving sulfamethoxazole and trimethoprim.
• The label advises to re-evaluate the benefit-risk of continuing therapy if a patient develops any sign of adverse reaction. Given the patient's high liver function test, it is recommended to exercise caution and consider alternative treatments or close monitoring of liver function tests if Bactrim is started 2.

From the Research

UTI Treatment with Bactrim

• The patient has been admitted for 3 days with high liver function test results, and the question is whether to start Bactrim (trimethoprim-sulfamethoxazole) for a urinary tract infection (UTI) 3.
• Bactrim is a commonly used antibiotic for UTIs, but it can cause side effects, including hepatic injury, although this is a rare event 3.
• The study from 1987 analyzed seven cases of co-trimoxazole-induced hepatic injury, which were accompanied by symptoms such as fever, rash, and eosinophilia 3.
• Another study from 2012 found that quinolones are increasingly favored over trimethoprim-sulfamethoxazole for empirical treatment of uncomplicated UTIs, due to increasing resistance to this broad-spectrum group of antibiotics 4.
• A 2016 study found that trimethoprim-sulfamethoxazole resistance rates were high in uncomplicated UTIs, and suggested that fosfomycin could be a viable option for treatment 5.

Liver Function Test Results

• Elevated liver function test results can be caused by various factors, including muscle damage-induced transaminitis, which may not be considered in the differential diagnosis 6.
• A 2015 study found that regular moderate physical activity can enhance liver health, but extremely prolonged competitive exercise may be harmful, particularly under harsh environmental conditions 7.
• The study from 2021 presented a case of an asymptomatic healthy male who had elevated transaminase levels due to vigorous exercise, which returned to normal after discontinuation of exercise 6.

Considerations for Starting Bactrim

• Given the patient's high liver function test results, it is essential to consider the potential risks of starting Bactrim, including the rare but possible risk of hepatic injury 3.
• The decision to start Bactrim should be based on the patient's individual circumstances, including the severity of the UTI, the presence of any underlying liver disease, and the potential benefits and risks of treatment 4, 5.