It is also useful for preventing hyperammonemia caused as a side effect of administration of valproic acid. Small intestine bacterial overgrowth
Lactulose is used as a test of small intestine bacterial overgrowth (SIBO). Recently, the reliability of it for diagnosing SIBO has been seriously questioned. A large amount of it is given with subsequent testing of molecular hydrogen gas in the breath. The test is positive if an increase in exhaled hydrogen occurs before that which would be expected by normal  digestion by the normal gut flora in the colon. An earlier result has been hypothesized to indicate digestion occurring within the small intestine. An alternate explanation for differences in results is the variance in small bowel transit time among tested subjects. Pregnancy
No evidence of harm to the baby has been found when used during pregnancy. It is generally regarded as safe during breastfeeding. Side effects
Common side effects of lactulose are abdominal cramping, borborygmus, and flatulence. In normal individuals, overdose is considered uncomfortable, but not life-threatening. Uncommon side effects are nausea and vomiting. In sensitive individuals, such as the elderly or people with reduced kidney function, excess lactulose dosage can result in dehydration and electrolyte disturbances such as low magnesium levels. Ingestion of lactulose does not cause a weight gain because it is not digestible, with no nutritional value. Although lactulose is less likely to cause dental caries than sucrose, as a sugar, a potential for this exists. This should be taken into consideration when taken by people with a high susceptibility to this condition.
If a person has a QTcF of > 500 ms or a significant ventricular arrythmia, bedaquiline and other QT prolonging drugs should be stopped.There is considerable controversy over the approval for the drug, as one of the largest studies to date had more deaths in the group receiving bedaquiline that those receiving placebo. Ten deaths occurred in the bedaquiline group out of 79, while two occurred in the placebo group, out of 81. Of the 10 deaths on bedaquiline, one was due to a motor vehicle accident, five were judged as due to progression of the underlying tuberculosis and three were well after the person had stopped receiving bedaquiline. However, there is still significant concern for the higher mortality in people treated with bedaquiline, leading to the recommendation to limit its use to situations where a four drug regimen cannot otherwise be constructed, limit use with other medications that prolong the QT interval, and the placement of a prominent black box warning. Drug interactions
Bedaquiline should not be co-administered with other drugs that are strong inducers or inhibitors of CYP3A4, the liver enzyme responsible for oxidative metabolism of the drug. Co-administration with rifampin, a strong CYP3A4 inducer, results in a 52% decrease in the AUC of the drug. This reduces the exposure of the body to the drug and decreases the antibacterial effect.