Long-term paracetamol use raises blood pressure: PATH-BP results

Paracetamol has often been cited as a safer alternative to non-steroidal anti-inflammatory drugs with regards blood pressure (BP) and cardiovascular health. However, the new PATH-BP trial, published in Circulation on February 7, 2022, casts doubt on the validity of this view.

In this double-blind, placebo-controlled, crossover study, 110 hypertensive individuals were randomized to receive 1 g acetaminophen 4× daily 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 BPs were 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.

One-hundred three patients completed both arms of the study. 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<0.0001) with a placebo-corrected increase of 4.7 mm Hg (95% CI, 2.9–6.6) and 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=0.005) with a placebo-corrected increase of 1.6 mm Hg (95% CI, 0.5–2.7). Similar findings were seen for 24-hour ambulatory and clinic BPs.

It is noteworthy, that patients in this study had pre-existing hypertension, which is an important limitation of this study. So further studies in people with normal healthy blood pressure, over longer time periods are needed to confirm the risks and benefits of using paracetamol more widely. In addition, these results do not apply to short-term use of paracetamol for headaches or fever, which is, of course, fine.


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