Common pain meds don't provide relief for most

Study finds that asipirin or acetaminophen were only effective 30 percent of the time

If you're suffering from acute pain, don't be surprised if aspirin or acetaminophen doesn't do the trick for you.

A new study finds that only about one-third of people who take one dose of aspirin (1,000 milligrams) or one dose of acetaminophen (600 mg) reported experiencing good pain relief.

Good relief was defined as feeling that the pain was cut by half for four to six hours.

The study reviewed 350 previous trials of pain medications that included 45,000 people in total. Close to 50 drugs or drug combinations were evaluated for their ability to relieve pain at specific doses.

Only 14 percent of patients who took codeine (60 mg) said they experienced good relief, the study showed.

With the best drugs, 70 percent or more said they experienced good pain relief. Examples of these drugs include etoricoxib at 120 mg and acetaminophen (500 mg) plus ibuprofen (200 mg), the study said.

No drug hit a home run — that is, no medication worked well for all patients. And in many cases, more than half of patients did not experience good pain relief, the researchers said.

The researchers emphasized that the effect of any drug at a particular dose will depend on the individual and the type of pain. Still, the new study may help inform doctors and patients to make decisions about which pain medications to use.

"This is the rock on which you can build good pain-relieving strategies for your hospital, for your patients, for your family, for yourself," study researcher Andrew Moore, a pain researcher at the University of Oxford in the United Kingdom

Pain medications
Moore and colleagues set out to review 35 other reviews from the journal The Cochrane Library. The researchers included studies in which participants were randomly assigned to receive a particular pain medication or a placebo to treat acute pain from surgery. Most of these studies involved people who had had their wisdom teeth removed.

For some medications, there was not enough information to say how well the drugs worked. Examples of these drugs include nabumetone and meloxicam, which are used to treat arthritis pain.

"Where there is no evidence of efficacy, the drugs in question should probably not be used to treat acute pain," the researchers said.

For 46 drugs or drug combinations, there was enough reliable information.

One way the researchers evaluated the drugs' effectiveness was to look at the number of people who would need to take that drug in order for one person to benefit (which they defined as relieving half of the pain). For some drugs, this number was low, around two people. For example, 2.5 people had to take 400 mg of ibuprofen in order for one person to benefit. For codeine at 60 mg, it was 12 people.

Drugs that lasted for more than eight hours included diunisal (sold as Dolobid) at 500 mg, oxycodone (10 mg) plus acetaminophen (650 mg), and celecoxib (400 mg; sold as Celebrex).

Hit or miss
Moore said that whether a particular drug works for someone is often hit or miss — people either experience great pain relief, or none at all.

"If the first painkiller a person tries doesn't seem to be working, then a doctor should look to find an alternative reliable drug and see if it is more effective in that individual patient. There are plenty of options that have a solid evidence base," Moore said.