Does paracetamol increase heart attack risk? New study findings for people with high blood pressure explained

Some people who take paracetamol regularly could be at increased risk of heart disease and strokes, new research suggests.

Until recently it has been assumed that paracetamol was a completely safe drug for patients with high blood pressure.

However, new findings indicate that the effect on people with the condition is similar to non-steroidal anti-inflammatories (NSAIDs), such as ibuprofen, which are known to increase blood pressure and risk of heart disease, and also used to manage chronic pain.

Researchers say that patients who have a long-term prescription for the painkiller, usually for the treatment of chronic pain, should be given the lowest effective dose for the shortest time possible.

What effect can paracetamol have on people with high blood pressure?

Experts say the increase in blood pressure could increase the risk of heart disease or stroke by around 20%.

They suggest the study should lead to a review of long-term paracetamol prescriptions to patients – particularly those with the condition, or those at particular risk of heart disease or stroke.

Professor James Dear, personal chairman of clinical pharmacology at the University of Edinburgh, said: “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.

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

He continued: “In summary, we’ve shown that two weeks of treatment with paracetamol increases blood pressure in patients who have hypertension (high blood pressure).”

Lead investigator Dr Iain MacIntyre, consultant in clinical pharmacology and nephrology at NHS Lothian, added: “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.”

The study found that after people stopped taking the drug, their blood pressure returned to what it was at the start of the study, suggesting the drug increased it.

One in three UK adults have high blood pressure

Researchers said they did not have accurate numbers of the people in the UK who are on paracetamol long term and have high blood pressure.

However, it is estimated that one in three UK adults have blood pressure increasing with age, while one in 10 people in Scotland – where the research was conducted – take paracetamol regularly, a figure that is likely to be similar elsewhere.

The study assessed 110 patients with a history of high blood pressure who were each prescribed 1g of paracetamol four times a day - a dose routinely prescribed for patients with chronic pain – or a placebo for two weeks each.

Findings showed there was a significant increase in blood pressure among those taking the painkiller, compared with those taking the placebo.

According to the experts, the study was set up to see a very small effect on blood pressure, but researchers were surprised to see a much bigger impact.

Prof Dear said the research indicates the findings could affect a large number of people, but scientists highlighted a limitation of their study was that it did not look at patients who have chronic pain.

However, there is no reason to think that patients who are taking paracetamol for treatment of pain would have a different blood pressure response to the patients in the study, researchers say.

Professor Sir Nilesh Samani, medical director at the British Heart Foundation, which funded the study, said: “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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