According to the findings of the PATH-BP (the PAraceTamol in Hypertension - Blood Pressure) trial, regular consumption of 4 g of Acetaminophen per day led to an approximate 5 mm Hg surge in systolic blood pressure among individuals with hypertension, as compared to placebo. 

Researchers sought to examine regular Acetaminophen dosing impact on blood pressure in hypertension-affected people.

This randomized study followed a double-blind, placebo-controlled, crossover design involving 110 participants. The participants were randomly assigned to get either 1 g of Acetaminophen four times daily or a placebo for a duration of two weeks. Subsequently, there was a two-week washout period before the participants switched to the alternate therapy. Ambulatory blood pressure measurements were taken at the beginning and end of each therapeutic period.

The key objective was to compare the alteration in mean daytime systolic blood pressure from baseline to the end of treatment between the study groups. A total of 103 patients completed both treatment arms of the study. The group receiving regular Acetaminophen exhibited a considerable rise in mean daytime systolic blood pressure (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]), with a placebo-adjusted rise of 4.7 mm Hg (95% CI, 2.9-6.6).

There was also a notable elevation in mean daytime diastolic blood pressure (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-adjusted rise of 1.6 mm Hg (95% CI, 0.5-2.7). Similar trends were witnessed for 24-hour ambulatory and clinic blood pressure measurements.

Hence, Acetaminophen raised blood pressure over a two-week period when compared with placebo in people suffering from hypertension. This elevation in  blood pressure heightens the risk of cardiovascular complications and raises concerns about the safety of using Acetaminophen regularly in such cases.