Study Questions Link Between Alli, Xenical and Liver Injury

A new study has failed to find any causal link between weight loss drugs containing orlistat and liver injuries, raising questions about prior research that suggested side effects of Xenical and Alli may damage the liver. 

A population based study published Friday in the British Medical Journal examined nearly 95,000 patients in the United Kingdom who received orlistat and registered with the UK Clinical Practice Research Datalink.

Xenical and Alli are obesity drugs which prevent the absorption of fats and are meant to be used alongside a reduced caloric diet. Both drugs use the active ingredient orlistat, which has been linked to concerns in recent years about a potential risk of liver damage, resulting in investigations by agencies in the United States and Europe.

Researchers found 988 cases of suspected acute liver injury with Xenical or Alli, with 335 of those cases being classified as definite liver injury and another 653 cases identified as probably cases. However, the increase in liver injury rates was the same just before users started taking the drugs as it was after the start of orlistat treatment.

“When the risk during the first 90 days of treatment was compared with the 90 days preceding first treatment, the incidence of liver injury was not increased,” researchers determined. “An analysis restricted to definite cases showed no evidence of an increased risk of liver injury during treatment.”

Researchers suggested that any association between use of Xenical or Alli and liver problems is likely due to underlying risks of acute liver injury due to obesity or other factors.

Concerns About Alli and Xenical Liver Side Effects

Xenical (orlistat 120mg) is a prescription medication that was approved by the FDA in1999 for weight loss. The lower dose Alli (orlistat 60mg) is an over-the-counter weight-loss drug that was approved i 2007.

In 2009, the FDA issued a warning about the potential risk of liver damage from Xenical and Alli, after an analysis of 32 case reports conducted between 1999 and 2008. The FDA warned consumers of rare reports of serious liver injury after use of the drugs. At least 13 cases of severe liver injury with Alli and Xenical were found during the investigation, including two incidents where patients died and three other incidents requiring patients to receive a liver transplant.

In 2010, the consumer watchdog group Public Citizen warned consumers against Xenical and Alli use due to minimal benefits provided in promoting weight loss compared to the risk of liver damage. The group petitioned federal drug regulators in 2011 to issue a recall for Xenical and Alli, citing concerns about the risk of liver damage associated with the medications.

European health officials launched an investigation into the Xenical and Alli liver damage side effects in 2011, but later decided against removing Xenical and Alli from the market, stating the health benefits outweighed the potential risk of liver injury.