Acetaminophen may boost blood pressure

Caution, attention should accompany routine use of any pain medicine.

For people with cardiovascular disease who need relief from aches and pains, acetaminophen (Tylenol, generic) has long been touted as a safer alternative to aspirin or nonsteroidal anti-inflammatory drugs (NSAIDs) like ibuprofen. A small but important Swiss trial warns that it may not be. This work doesn't mean you should ditch acetaminophen if it helps you, but does suggest you should give it the caution that it — and every medication — deserves.

The Swiss team set out to fill a surprising gap in medical knowledge: the effect of acetaminophen on blood pressure among people with coronary artery disease. This includes folks with angina (chest pain with exercise or stress) along with anyone who has had bypass surgery or angioplasty or who has been diagnosed with cholesterol-clogged arteries.

The researchers asked 33 men and women with one or more of these problems to take either 1,000 milligrams (mg) of acetaminophen or an identical placebo three times a day for two weeks. Then, after a two-week break, each volunteer took the other treatment. The amount of acetaminophen used in the study is a standard daily dose for pain.

When the participants took acetaminophen, average systolic blood pressure (the top number of a blood pressure reading) increased from 122.4 to 125.3, while the average diastolic pressure (the bottom number) increased from 73.2 to 75.4 (Circulation, Nov. 2, 2010). Blood pressure stayed steady when participants took the placebo. These increases aren't large. But they indicate that acetaminophen, like NSAIDs, somehow affects the cardiovascular system.

A larger, longer trial would have given more reliable results. It would also have been unethical, since none of the participants were in pain. That means they couldn't reap any benefit from acetaminophen, but could only be harmed by it.

Making choices

The sudden removal of the popular painkiller Vioxx from the market in October 2004 over concerns that it caused cardiovascular problems put all pain relievers under the spotlight — except acetaminophen. It avoided the "black box" warning about increased risk of cardiac problems that the FDA now requires on the labels of all NSAIDs. And the American Heart Association later recommended it as a safe alternative to NSAIDs.

Acetaminophen is easier on the stomach than aspirin and other NSAIDs, and is probably a good option for people who take warfarin (Coumadin, Jantoven, generic) or clopidogrel (Plavix). But because it is so widely used and perceived as safe, people tend to take it without thinking, one reason acetaminophen is a leading cause of liver failure and transplantation in the United States.

If you have some form of cardiovascular disease, it makes sense to take acetaminophen rather than an NSAID for a fever, headache, pulled muscle, or other occasional problem. But if you need relief every day for pain from osteoarthritis or rheumatoid arthritis, acetaminophen may not be a better option than an NSAID — it doesn't work that well against inflammatory pain and, like an NSAID, may slightly elevate blood pressure.

The key message from this study is that acetaminophen isn't free from cardiovascular side effects. It is worth a try as a first-line drug for pain relief, but if it doesn't control your pain, it is reasonable to switch to an NSAID.