TUESDAY, March 3, 2015 (HealthDay News) -- Acetaminophen may not be as safe as previously thought, with larger doses and long-term use linked to increased risk of health problems, a new report contends. The findings were published online March 2 in the Annals of the Rheumatic Diseases.
Philip Conaghan, M.B.B.S., a professor with the Leeds Institute of Rheumatic and Musculoskeletal Medicine in the United Kingdom, and colleagues reviewed 1,888 studies related to the use of acetaminophen. They settled on eight studies that met the standards for their review. The studies involved more than 665,000 people in the United States, Britain, Denmark, and Sweden. People reported their acetaminophen use, and researchers tracked any health problems they might have. Heavy use of acetaminophen is associated with kidney disease and bleeding in the digestive tract, and also has been linked to increased risk of myocardial infarction, stroke, and hypertension, the study authors noted. One cited study indicates that overuse of acetaminophen can increase a person's risk of early death as much as 60 percent.
Because the studies were observational, they don't prove a cause-and-effect relationship between acetaminophen and these health problems. Other medications taken also might have contributed to the health problems observed in these studies, the paper's authors noted. The studies also differed in how patients' acetaminophen use was calculated, Conaghan told HealthDay. Some studies estimated lifetime intake, while others reported the amount taken each day, week or month -- making it impossible to draw firm conclusions about what constitutes a "safe" dose. The study authors are calling for a new systematic review of acetaminophen's effectiveness and safety, saying that the medication's true risks are "higher than that currently perceived in the clinical community."
The studies weren't clinical trials, noted Tylenol's manufacturer, McNeil Consumer Healthcare. "McNeil Consumer Healthcare is committed to providing consumers with safe and effective over-the-counter medicines and recommends consumers always read and follow the product label," a statement from the company reads. "If consumers have questions regarding the products they are taking, we encourage them to contact their doctor or pharmacist."