Paracetamol has often been cited as a safer alternative to non-steroidal anti-inflammatory drugs (NSAIDs) with regards blood pressure and cardiovascular health. But now researchers have raised concerns about this, suggesting that those taking paracetamol long-term may be at greater risk of heart attack and stroke.

Long-term paracetamol use could increase the risk of heart disease and strokes in people with high blood pressure, a study suggests.

Clinical trial

In the first large randomised clinical trial to address whether paracetamol has an effect on blood pressure, researchers from University of Edinburgh performed a double-blind, placebo-controlled, cross-over study with 110 individuals, all of whom had hypertension.

In the latest study, all patients with a history of high blood pressure were prescribed one gram of paracetamol four times a day – a routinely prescribed dose in patients with chronic pain – or a matched placebo for two weeks. All patients received both treatments, with the order randomised and blinded.

Findings

In their study, published in the scientific journal Circulation, the researchers found that those prescribed paracetamol saw a significant increase in their systolic blood pressure of around 5 mmHg, compared with those taking the placebo.

The rise in blood pressure was similar to that seen with NSAIDs and might be expected to increase the risk of heart disease or stroke by around 20%.

The research team says the findings should lead to a review of long-term paracetamol prescriptions to patients – particularly those with high blood pressure, or those at particular risk of heart disease or stroke.

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.

Suggestions for Clinicians

Doctors and patients together should consider the risks versus the benefits of long-term paracetamol prescription, especially in patients at risk of cardiovascular disease.

Researchers 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.

Given the substantial rises in blood pressure seen in some of the 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.

Though further research in people with normal, healthy blood pressure, over a longer timeframe, was needed to confirm the risks and benefits of using paracetamol more widely.

Conclusion

This research shows how quickly regular use of paracetamol can increase blood pressure in people with hypertension who are already at increased risk of heart attacks and strokes. It emphasises why doctors and patients should regularly review whether there is an ongoing need to take any medication, even something that may seem relatively harmless like paracetamol, and always weigh up the benefits and risks. 

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