How do lactulose and rifaximin work in the treatment of cirrhosis?

Lactulose and rifaximin are utilized in treating cirrhosis primarily for their roles in reducing ammonia levels in the body, which is crucial in managing hepatic encephalopathy.

Lactulose is a synthetic sugar that, when ingested, is not absorbed in the intestine and instead helps to lower blood ammonia levels. It accomplishes this by drawing water into the intestinal lumen, which facilitates the elimination of ammonia through the stool. Additionally, it alters colonic pH, promoting the growth of non-urease-producing bacteria that help convert ammonia into less toxic substances, further contributing to ammonia reduction.

Rifaximin is an antibiotic that targets certain gut bacteria, inhibiting their growth. This can decrease the production of ammonia because it reduces the bacterial load that generates ammonia from dietary proteins in the intestines. The combined action of both lactulose and rifaximin effectively addresses the elevated ammonia levels often seen in patients with cirrhosis, thereby mitigating the risk of encephalopathy and improving overall neurological function.

The other options do not accurately reflect the mechanisms of lactulose and rifaximin in the context of cirrhosis treatment.