Paracetamol is one of the most widely used painkillers in the world.
It is often recommended when people need pain relief but want to avoid non-steroidal anti-inflammatory drugs, or NSAIDs, which can raise blood pressure and increase heart risks in some patients.
In the United States, paracetamol is better known as acetaminophen.
It is commonly used for headaches, fever, muscle pain and other short-term problems, while some people also take it regularly for long-lasting conditions such as arthritis and chronic back pain.
Because paracetamol is not an NSAID, it has often been considered a safer choice for people who have heart or blood pressure concerns. However, research from the University of Edinburgh suggests that regularly taking high doses may also affect the cardiovascular system.
The study focused on people who already had high blood pressure, also called hypertension. High blood pressure makes the heart work harder and, over time, can damage blood vessels and increase the risk of heart attack, stroke and other health problems.
Researchers studied 110 adults with a history of high blood pressure. The participants were randomly assigned to take either paracetamol or a placebo, a pill with no active medicine, during different parts of the study.
The paracetamol dose was one gram four times a day, for a total of four grams daily. This is a commonly used maximum daily dose and can be prescribed to some people who need regular treatment for chronic pain.
Each treatment period lasted two weeks. By comparing the same participants while they were taking paracetamol and while they were taking the placebo, the researchers could more clearly examine whether the medicine itself affected blood pressure.
The results showed that blood pressure increased when participants took paracetamol regularly. The rise was seen in both the top and bottom blood pressure numbers and was similar in size to increases previously linked with some NSAIDs.
This matters because even a relatively small rise in blood pressure can become important when it continues over a long period. The researchers estimated that an increase of this size, if sustained, could be associated with roughly a 20% higher risk of heart disease or stroke.
The study does not mean that taking an occasional paracetamol tablet for a headache or fever will cause heart disease. The researchers were specifically studying regular use of a high daily dose in people who already had high blood pressure.
The findings therefore raise a different question: whether doctors should be more cautious when prescribing paracetamol every day for months or years to people who already have an increased risk of cardiovascular disease.
For these patients, the researchers suggested starting with the lowest effective dose when long-term paracetamol treatment is needed. Blood pressure may also need to be monitored after treatment begins, particularly in people who already have hypertension.
Patients should not stop prescribed pain medicine without discussing it with a healthcare professional. Chronic pain can seriously affect sleep, movement and quality of life, so treatment decisions need to balance effective pain control against possible side effects.
Other approaches may sometimes help reduce the amount of medicine needed. Depending on the cause of pain, these can include physical therapy, suitable exercise, weight management or other treatments recommended by a doctor.
The research was led by Iain MacIntyre and colleagues at the University of Edinburgh and was published in the journal Circulation. The study adds to growing evidence that even very familiar medicines can have effects that deserve closer attention when they are taken regularly.
Paracetamol remains an important and useful medicine for many people. But the findings suggest that its long-term use should not automatically be considered free of cardiovascular risk, especially for people who already have high blood pressure.
If you care about blood pressure, please read studies about how diets could help lower high blood pressure, and 3 grams of omega-3s a day keep high blood pressure at bay.
For more health information, please see recent studies about how tea and coffee influence your risk of high blood pressure, and results showing this olive oil could reduce blood pressure in healthy people.
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