Women taking daily amounts of non-aspirin painkillers are more likely to develop high blood pressure than those who don't, a new study suggests.

While many popular over-the-counter painkillers have been linked before to high blood pressure, acetaminophen, sold in many countries as Tylenol, has generally been considered relatively free of such risk, a study published online on August 15 in the American Heart Association journal Hypertension said.

It is the only one that is not a non-steroidal anti-inflammatory drug or NSAI, a class of medications the US federal government just required to carry stricter warning labels because of the risk of heart-related problems. Those include ibuprofen (often sold as Advil and Motrin) and naproxen (sold as Aleve). Many had turned to those painkillers in the wake of problems with prescription drugs, such as Vixx.

However, the new study found that women taking Tylenol were about twice as likely to develop blood pressure problems.

Risk also rose for women taking NSAIDS other than aspirin.

"If you're taking these over-the-counter medications at high dosages on a regular basis, make sure you report it to your doctor and check your blood pressure regularly," said Dr Christie Ballantyne, a cardiologist at the Methodist DeBakey Heart Center in Houston who had no role in the study.

The research found aspirin still remains the safest medicine for pain relief. It has long been known to reduce the risk of cardiovascular problems and was not included in the government's requirement for stricter labels for NSAIDs.

The study involved 5,123 women participating in the Nurses Health Study at Harvard Medical School and Brigham and Women's Hospital in Boston.