Men who take pain relievers such as acetaminophen, ibuprofen and ASA may have an increased risk of high blood pressure, U.S. researchers say.

The medications are the three most commonly used drugs in the U.S., according to background information in the study. 

"These data add further support to the hypothesis that non-narcotic analgesics independently elevate the risk of hypertension," the study's authors wrote in Tuesday's Archives of Internal Medicine.

"Given their common consumption and the high prevalence of hypertension, our results may have substantial public health implications and suggest that these agents be used with greater caution."

Previous large studies in women have suggested frequent use of ASA and non-steroidal anti-inflammatory drugs or NSAIDs, such as ibuprofen — perhaps as little as once or twice a week — is linked to an increased risk of hypertension.

Dr. Gary Curhan of Harvard Medical School in Boston, Mass., and his team looked for the link in 16,000 male health professionals who had no history of high blood pressure when the study began.

When the researchers checked the health records of participants for four years, they found men who took acetaminophen, sold generically and under the brand name Tylenol, for six or seven days a week were 34 per cent more likely to be diagnosed with hypertension than men who did not take pain relievers.

Men who took Aspirin regularly were 26 per cent more likely to have high blood pressure than non-users, the team found. 

Among those taking NSAIDs such as ibuprofen and naproxen, the increased risk was 38 per cent.

For men who took 15 or more of the pills each week, the risk of hypertension was 48 per cent higher than among non-users.

Be cautious when prescribing: heart association

All three classes of drugs may block the effects of chemicals that relax blood vessels to decrease blood pressure, the researchers suggested. Acetaminophen may also affect cells lining blood vessels and impair cells' ability to work when stressed by high levels of oxygen.

Despite the results, men who are prescribed Aspirin to reduce their risk of heart attack and stroke should continue to take it, Curhan said.

But doctors should be more cautious about prescribing arthritis medications known as COX-2 inhibitors, the American Heart Association said in an advisory based partly on the study's findings.

The association suggested that before doctors hand out prescriptions, they should tell patients to try physical therapy, exercise and weight loss to reduce stress on joints and heat or cold therapy.