Paracetamol for pain relief after surgical removal of lower wisdom teeth

The commonly used and inexpensive analgesic acetaminophen (Tylenol or paracetamol) is an effective pain reliever after surgical removal of lower wisdom teeth, according to a new systematic review of 21 studies.

The most effective dose appears to be 1,000 milligrams taken at six-hour intervals, the review concludes.

“Acetaminophen has been around a long time. It has a good safety record and is widely available without prescription. Our findings suggest it is a good choice for dental pain,” said review co-author Kiaran Weil.

The review appears in the latest issue of The Cochrane Library , a publication of The Cochrane Collaboration, an international organization that evaluates medical research. Systematic reviews draw evidence-based conclusions about medical practice after considering both the content and quality of existing medical trials on a topic.

Researchers from the University of Manchester School of Dentistry in England and the University of Amsterdam in the Netherlands analyzed the studies.

The review examined data from 1,968 patients enrolled in studies that compared the effectiveness of acetaminophen versus placebo to decrease pain after surgical extraction of the third molars, or lower wisdom teeth. The review included patients who received local anesthesia, intravenous sedation or general anesthesia; however, it excluded patients who took pain relievers at the time of surgery.

All patients reported moderate to severe pain just after surgery. Researchers tallied the number of patients who reported 50 percent pain relief at four and six hours after surgery.

Patients who received any dose of acetaminophen after surgery were at least three times more likely to report 50 percent pain relief than patients who took a placebo. However, patients given the higher dose of 1,000 milligrams were four to five times more likely to report that their pain was cut in half. Study participants who took less than 1,000 milligrams were about twice as likely to report 50 percent pain relief.

Patients treated with acetaminophen reported a similar number of side effects as patients who received a placebo. However, researchers monitored patients taking acetaminophen, and Weil cautions that side effects are less likely to occur under controlled circumstances.

The maximum recommended dose of acetaminophen is 4,000 milligrams per day for adults.

Acetaminophen can cause liver toxicity when an individual exceeds the maximum daily dose. Heavy drinkers, malnourished patients and people with AIDS or anorexia nervosa also have an increased risk for liver toxicity.

While the review shows acetaminophen is effective for pain relief, oral surgeon Morton Rosenberg said many dentists prescribe analgesics plus narcotic pain relievers after surgical removal of wisdom teeth.

“This is a procedure where the dentist is working on bone and cutting oral tissue. These are some of the strongest stimuli for pain that we know of,” said Rosenberg, professor of oral and maxillofacial surgery at Tufts University School of Dental Medicine in Boston.

In his practice, Rosenberg treats pain after wisdom tooth removal on a case-by-case basis.

“It varies so much from patient to patient that it is hard to generalize. I do often give a prescription for something like Tylenol with codeine and advise the patient to fill the prescription if needed,” he said. Many patients expect to receive something stronger than an over-the-counter medication, he added.

Future reviews of studies will compare acetaminophen directly to other pain relievers such as ibuprofen.

Weil K, et al. Paracetamol for pain relief after surgical removal of lower wisdom teeth. (Review) Cochrane Database of Systematic Reviews 2007, Issue 3.

The Cochrane Collaboration is an international nonprofit, independent organization that produces and disseminates systematic reviews of health care interventions and promotes the search for evidence in the form of clinical trials and other studies of interventions. Visit http://www.cochrane.org more information.