The objective of this study is to monitor liver function tests (blood levels of an indicator of liver function) of healthy people taking the maximum labeled daily dose of acetaminophen compared to people taking placebo for 16 to 40 days.
Those people that continue to have normal liver tests after 16 days will have completed their part of the study. People that develop abnormal liver function tests will continue taking acetaminophen or placebo, and have their liver tests monitored closely for up to an additional 24 days. This is to (1) make sure these tests return to normal and (2) determine when these tests return to normal while still taking acetaminophen or placebo.
If at any time the liver tests indicate anything more than a minor increase, you would be immediately told to stop taking the study drug.