Long-term use of acetaminophen appears to be associated with a significant increase in blood pressure (BP), according to a study published in Circulation.
“Regular daily intake of acetaminophen 4 g increases systolic blood pressure in individuals with hypertension by about 5 mm Hg when compared with placebo,” wrote Iain MacIntyre, MD, Royal Infirmary of Edinburgh, National Health Service Lothian, United Kingdom, and colleagues. “This increases cardiovascular risk and calls into question the safety of regular acetaminophen use in this situation.”
In the double-blind, placebo-controlled, crossover study, 103 individuals were randomised to receive acetaminophen 1 g 4 times per day or matched placebo for 2 weeks followed by a 2-week washout period before crossing over to the alternate treatment. At the beginning and end of each treatment period, 24-hour ambulatory BP was measured.
The primary outcome was a comparison of the change in mean daytime systolic BP from baseline to end of treatment between the placebo and acetaminophen arms.
Regular acetaminophen, compared with placebo, resulted in a significant increase in mean daytime systolic BP (132.8 ± 10.5 to 136.5 ± 10.1 mm Hg [acetaminophen] vs 133.9 ± 10.3 to 132.5±9.9 mm Hg [placebo]; P < .0001), with a placebo-corrected increase of 4.7 mm Hg. Acetaminophen use also resulted in a significant increase in mean daytime diastolic BP (81.2 ± 8.0 to 82.1 ± 7.8 mm Hg [acetaminophen] vs 81.7 ± 7.9 to 80.9 ± 7.8 mm Hg [placebo]; P = .005), with a placebo-corrected increase of 1.6 mm Hg. Similar findings were seen for 24-hour ambulatory and clinic BPs.
“This is not about short-term use of paracetamol for headaches or fever, which is, of course, fine, but it does indicate a newly discovered risk for people who take it regularly over the longer term, usually for chronic pain,” said Dr. MacIntyre.
“This study clearly shows that paracetamol — the world’s most used drug — increases blood pressure, one of the most important risk factors for heart attacks and strokes,” said James Dear, University of Edinburgh. Doctors and patients together should consider the risks versus the benefits of long-term paracetamol prescription, especially in patients at risk of cardiovascular disease.”
“We would recommend that clinicians start with a low dose of paracetamol, and increase the dose in stages, going no higher than needed to control pain,” added David Webb, University of Edinburgh. “Given the substantial rises in blood pressure seen in some of our patients, there may be a benefit for clinicians to keep a closer eye on blood pressure in people with high blood pressure who newly start paracetamol for chronic pain.”