Sulfamethoxazole/Trimethoprim Outperforms Ciprofloxacin for Preventing SBP Recurrence in Cirrhosis

Patients with cirrhosis and ascites who develop spontaneous bacterial peritonitis (SBP) are routinely given prophylactic antibiotics to prevent recurrence. Now, a large new retrospective study by Cleveland Clinic researchers suggests that sulfamethoxazole/trimethoprim may be a more effective antibiotic in most patients.

It’s the first study to compare sulfamethoxazole/trimethoprim with ciprofloxacin, the two antibiotics most often prescribed for SBP. Researchers found that sulfamethoxazole/trimethoprim was associated with significantly better outcomes across almost all measured endpoints, including recurrence.

“I’m surprised,” says Cleveland Clinic hepatologist and senior author Dian Chiang, MD, MPH. “I was expecting the results would be similar and there would not be a significant difference.”

He notes that, between the two drugs, ciprofloxacin is more commonly prescribed for SBP.

Spontaneous bacterial peritonitis is the most common complication that results in hospitalization for people with cirrhosis and ascites and is also one of the most common triggers for cirrhosis decompensation. Guidelines call for prescribing prophylactic antibiotics after the first episode of SBP to prevent recurrence; however, the most used antibiotics have never been compared.

“We wanted to figure out which one works better in this very sick population,” Dr. Chiang explains.

Data from a large patient pool

For the new study, researchers used the TriNetX research network to analyze data on more than 11,100 patients prescribed sulfamethoxazole/trimethoprim and nearly 20,000 who received ciprofloxacin.

SBP recurrence was lower in the sulfamethoxazole/trimethoprim group, as was all-cause mortality. The patients who received sulfamethoxazole/trimethoprim also had lower incidence of ascites, hepatic encephalopathy, and variceal bleeding.

Although they were surprising, the results made sense, Dr. Chiang says.

“We know that resistance to quinolones, which is the class of medication that includes ciprofloxacin, is increasing in the U.S., so to some degree we were expecting that over time people may lose their response to this antibiotic,” he explains. “However, at the same time, we didn’t have concrete data to know whether sulfamethoxazole/trimethoprim can be better or more effective than ciprofloxacin.”

But while the study provided important information, he adds that physicians ordering antibiotics should continue to consider factors like the patient’s prior history of infection, antibiotic use, drug interactions and past side effects when making prescription decisions.

Next steps

The research group plans to study how geographic variations in antibiotic resistance affect outcomes between the two drugs.

“The challenge of using antibiotics is that local antibiotic susceptibility and resistance may vary,” says Dr. Chiang. “So, identifying local resistance patterns may help guide physicians.”

The study, “Secondary Prophylaxis of SBP in Cirrhosis: Bactrim vs. Ciprofloxacin in a Propensity-Matched Real-World Study,” is to be presented at this year’s American College of Gastroenterology meeting.