Does acetaminophen activate endogenous pain inhibition in chronic fatigue syndrome/fibromyalgia and rheumatoid arthritis? A double-blind randomized controlled cross-over trial.
Meeus, Mira, Ickmans, Kelly, Struyf, Filip et al.·Pain physician·2013
This study tested whether acetaminophen (Tylenol) could help improve how the body's natural pain-blocking systems work in people with ME/CFS combined with fibromyalgia, compared to people with rheumatoid arthritis and healthy people. Researchers measured pain responses before and after taking acetaminophen or a placebo. The results were mixed: acetaminophen slightly helped pain thresholds in ME/CFS patients but actually made things slightly worse in arthritis patients and healthy controls, suggesting the drug affects different people very differently.