Choosing a painkiller off the drug store shelf can be, well, painful. To offer some relief, Consumer Reports Health released its "Best Buy Drugs" -- a 22-page report that compares the effectiveness, safety and price of some of the top brands (and generics) for pain killing.
The report focuses on non-steroidal anti-inflammatories (NSAIDs), which commonly are used to treat pain associated with arthritis.
But NSAIDs are only one type of painkiller. Depending on the ache, another type might be better. And depending on the sufferer, some drugs can be dangerous.
ABC News asked pain experts to weigh in on what drugs to take for various aches and pains, and when to avoid the drugs.
The drug commonly referred to as aspirin has been around since 400 B.C., when people used salicin-containing willow tree bark to treat pain and inflammation. It was the discovery of salicin as the bark's pain relieving ingredient that led the development of stomach-friendlier acetylsalicylic acid (ASA) in 1838.
"Aspirin was the 'original' headache medication," said Dr. Timothy Collins, associate professor of medicine and neurology at Duke University Medical Center's Pain and Palliative Care Clinic.
But acetylsalicylic acid's anti-inflammatory properties make it good for other types of pain, too, including muscle pain, joint pain from arthritis and toothaches. It's also relatively cheap.
The drug is an NSAID that works by suppressing the production of prostaglandins -- hormone-like molecules that play an important role in inflammation. Unfortunately, the same molecules help to protect the stomach lining.
Acetylsalicylic acid also interferes with blood-clotting thromboxanes. Some people take a daily dose to reduce the risk of heart attack and stroke.
Because of its effects on the stomach and the blood, acetylsalicylic acid isn't right for everyone. People with ulcers, bleeding disorders or kidney or liver problems should avoid it, as should anyone who might be allergic to it.
"There are a lot of other non-steroidal anti-inflammatory drugs (NSAIDs) that have fewer side effects than aspirin so, in many cases, aspirin is not a first choice," said Dr. Mike Schmitz, director of pediatric pain medicine at Arkansas Children's Hospital in Little Rock.
Acetylsalicylic acid use in kids with fevers has been linked to Reye's syndrome -- a potentially fatal disease that attacks the brain and liver. It should only been used in people under 19 under specific orders from a doctor.
Another NSAID, ibuprofen, has pain relieving effects similar to those of acetylsalicylic acid. But it tends to work better even at a lower dose and have milder side effects.
"It is a very good anti-inflammatory medication, originally developed to treat arthritis," said Duke's Collins. "It also lowers fever, and helps with symptoms from the common cold."
The brand name version of ibuprofen is Advil. But only the generic form of ibuprofen was named a "best buy" NSAID by Consumer Reports Health today.
Like acetylsalicylic acid, ibuprofen inhibits prostaglandin synthesis. So it can irritate the stomach and increase the risk for ulcers. It also can cause bruising and bleeding in people who use blood thinners. Ibuprofen should be avoided in people with ulcers, bleeding disorders or kidney disease. But it is not associated with Reye's syndrome and, therefore, can be used in children.
A relative newcomer to the pharmacy shelves, naproxen (Aleve) only was approved by the Food and Drug Administration for over-the-counter use in 1994.
Naproxen is an NSAID with a pain-killing mechanism similar to that of ibuprofen. The drugs have comparable effects and side effects, so the choice comes down to personal preference.
"The anti-inflammatory medications like ibuprofen and naproxen are very good for the common muscle aches from 'overdoing it' (like at the gym or working in the yard) and also help with common arthritis pain," said Collins.
Naproxen -- both Aleve and the generic form -- also was named a "best buy" NSAID by Consumer Reports Health.
When taking NSAIDs, hydration is important because the drugs may reduce blood flow to the filtering mechanism of the kidneys. According to the National Institutes of Health, NSAIDs other than acetylsalicylic acid also can increase the risk of stroke and heart attack.
Talk to a doctor about cardiovascular risk factors before taking NSAIDs regularly.
The drug known by most people as Tylenol is another mild pain reliever. It is not an NSAID, so it won't quell inflammation. However, it won't irritate the stomach, either.
"Acetaminophen is better for people who have stomach troubles," Schmitz said. "It has been a good drug for children as well."
The drug is good for treating aches and pains not related to injury or inflammation. But because it's metabolized in the liver, it can have serious side effects if taken at high doses or with alcohol.
"The most significant danger of high doses acetaminophen is liver damage and even liver failure," said Dr. Doris Cope, professor and vice chairman of pain at the University of Pittsburgh School of Medicine.
Acetaminophen use should be avoided in people who have consumed alcohol or are dehydrated, or who have kidney or liver problems.
Because of its potential to cause serious harm at high doses, people should be careful when taking combination drugs that contain acetaminophen, according to Dr. Carol Warfield, chair of anesthesia, critical care and pain medicine at Beth Israel Deaconess Medical Center in Boston.
Certain prescription painkillers also contain acetaminophen, opening the door for unintentional overdoses.
"In a recent study, fewer than 15 percent of patients knew that commonly prescribed pain medications [such as Percocet and Vicodin] contained acetaminophen," said the University of Pittsburgh's Cope.
Over-the-counter medications designed to treat multiple symptoms often contain painkillers in combination with other drugs. Cold and flu medications often contain painkillers as well as decongestants. And menstrual pain relievers often provide diuretics, too.
"I am not a big fan of combination drugs," Schmitz said. "I recommend that people know what they are taking, take specific medicines for specific problems or symptoms, and read the package before they purchase it so that they know what is in it."
Talk to a Doc
When in doubt, ask a doctor or pharmacist for a recommendation or an explanation of a particular drug's ingredients. And during pregnancy, it's important to talk to a doctor before taking any over-the-counter medication.
"It's not a bad idea to find out what might be OK before one needs any OTC medicine at the first OB visit," Schmitz said.