Used to be, aspirin and other salicylates were the only medications available for nonprescription relief of minor ailments- -from headaches and fever to muscle strain and minor arthritis. Today, consumers looking for temporary relief from such garden- variety ills have their pick of what can be a bewildering array of "regular," "extra-strength," and "maximum pain relief" tablets, caplets and gel caps on the drugstore shelf.

Though this cornucopia can seem confusing, the products' pain- relieving ingredients fall into just four categories: aspirin (and other salicylates), acetaminophen, ibuprofen, and naproxen sodium. For the most part, these over-the-counter (OTC) analgesic ingredients are equally effective. However, some may be more effective for certain types of ailments, and some people may prefer one type to another because of their varying side effects. "Knowing the pros and cons of each type of pain reliever will allow you to choose among them," says William T. Beaver, M.D., professor of pharmacology and anesthesia at Georgetown University School of Medicine in Washington, D.C.

Old Faithful

Americans have been reaching for aspirin for almost 100 years as an all-purpose pain reliever (see "Aspirin: A New Look at an Old Drug" in the January-February 1994 FDA Consumer). Aspirin (or acetylsalicylic acid) works in part by suppressing the production of prostaglandins, hormone-like substances that have wide-ranging roles throughout the body, such as stimulating uterine contractions, regulating body temperature and blood vessel constriction, and helping blood clotting. "Regular" strength aspirin contains 325 milligrams (mg) per tablet; "extra" or "maximum" strength, 500 mg per tablet. The usual adult (defined as 12 years and older) dosage is one to two 325-mg aspirin tablets every four hours.

Some manufacturers add caffeine to aspirin. "There is no evidence that caffeine relieves pain, but it can enhance the effects of aspirin, possibly by lifting a person's mood," says Michael Weintraub, M.D., director of FDA's Office of OTC Drug Evaluation. Since a two-tablet dose provides roughly the same amount of caffeine as a cup of coffee, you can get the same effect by taking two plain aspirin with coffee.

To minimize the stomach irritation aspirin can cause, some brands are "buffered" with calcium carbonate, magnesium oxide, and other antacids or coated so the pills don't dissolve until they reach the small intestine. Buffered formulas may offset aspirin's directly irritating effects on the stomach lining. They may be useful for people who get heartburn or stomach pain when they take aspirin, as well as for those with arthritis, who need to take as much as 4,000 mg every day.

Aspirin also causes gastrointestinal (GI) upset indirectly (by inhibiting production of a prostaglandin that protects the stomach lining by stimulating mucus production); buffering does nothing to offset this effect.

The downside of coated aspirin products is that they may take up to twice as long to provide pain relief as plain aspirin, according to Weintraub. Last September, an FDA advisory panel recommended that labels on products containing aspirin warn that heavy drinkers are especially vulnerable to developing GI bleeding.

Aspirin should not be taken by people who have:

• ulcers, because it can worsen symptoms
• asthma, because it can trigger an attack in some asthmatics
• uncontrolled high blood pressure, because of an increased risk of one type of stroke
• liver or kidney disease, because it may worsen these conditions
• bleeding disorders or who are taking anticoagulant medication, because it may cause bleeding.

Continual high dosages of aspirin can cause hearing loss or tinnitis — a persistent ringing in the ears.

FDA requires products containing aspirin and other salicylates to carry a label warning that children and teenagers should not use the medicine for chickenpox or flu symptoms because of its association with Reye syndrome, a rare disorder that may cause seizures, brain damage, and death.

The label also alerts pregnant women that use of aspirin in the last trimester may increase the risk of stillbirth and of maternal and fetal bleeding during delivery.

One Aspirin Alternative

Twenty years ago, FDA approved acetaminophen (Tylenol, and other brands and generics) in dosages of 325 mg and 500 mg for OTC use. "Nobody knows exactly how acetaminophen works, but one theory is that it acts on nerve endings to suppress pain," says Weintraub. Acetaminophen is as effective as aspirin in relieving mild-to- moderate pain and in reducing fever, but less so when it comes to soft tissue injuries, such as muscle strains and sprains, he adds. The usual adult dosage is two 325-mg tablets every four hours.

Acetaminophen-based products to ease menstrual cramps often contain other ingredients, such as pamabrom (a diuretic) or pyrilamine maleate (an antihistamine used for its sedative effects). "While these ingredients are safe, they have not been proven effective against uterine cramps, although they may relieve other symptoms associated with menstrual pain," says Weintraub.

Though acetaminophen is no better or faster at pain relief than aspirin, the drug is gentler on the stomach and reduces fever without the risk of Reye syndrome. However, even at moderate doses, acetaminophen can cause liver damage in heavy drinkers. At press time, FDA was planning to require a warning about this on the labels of OTC products containing the drug.

From Rx to OTC

Like aspirin, ibuprofen and naproxen sodium inhibit prostaglandin production. However, they are more potent pain relievers, especially for menstrual cramps, toothaches, minor arthritis, and injuries accompanied by inflammation, such as tendinitis. FDA approved ibuprofen for OTC marketing in 1984 at a dosage level of 200 mg every 4 to 6 hours, and naproxen sodium in 1994 at a dosage level of 200 mg every 8 to 12 hours.

"Ibuprofen and naproxen sodium were converted to OTC status after their manufacturers did the necessary studies to show that these pain relievers were effective at OTC dosages, which are lower than prescription dosages," explains Weintraub. The lowest dosage strength for prescription-strength ibuprofen (Motrin and others) is 300 mg per tablet, and 275 mg per tablet for the prescription version of naproxen sodium (Anaprox, for example). "In addition, the pharmaceutical companies had to show that these drugs were safe for use by a larger, more varied group of people [than would have received them by prescription only] and that the drugs were safe to use without medical supervision, as is the case with all nonprescription drugs."

Taken at the recommended adult dosage, OTC ibuprofen (Advil and others) and naproxen sodium (Aleve) are somewhat gentler on the stomach than aspirin. However, people who have ulcers or who get GI upset when taking aspirin should avoid both. In addition, asthmatics and people who are allergic to aspirin should avoid ibuprofen and naproxen sodium. An FDA advisory panel has recommended labeling on ibuprofen products like that recommended for aspirin, warning heavy drinkers about increased risk of gastric bleeding and impaired liver function (products with naproxen sodium labels already include this information).

Although ibuprofen and naproxen sodium interfere with blood clotting much less than aspirin does, they should not be used by people who have bleeding disorders or who are taking anticoagulants. Children under 12 should not be given either drug, except under a doctor's supervision, and people over 65 are advised to take no more than one naproxen sodium tablet every 12 hours.

Choosing an OTC pain reliever involves balancing effectiveness for a particular ailment with side effects. Often this is a very individual choice, based in part on your health history and how the drug affects you. Regardless of which type of OTC pain reliever you choose, remember that it is intended to be used on a short-term basis, unless directed by a doctor, cautions Weintraub. The warning labels on these products include limitations on duration of use to ensure that chronic or serious illnesses are not masked. Typically, labels advise against taking the product for more than 10 days to relieve pain (for children, the upper limit is five days), or more than three days to reduce fever. If symptoms worsen, pain persists, or there is redness or swelling, medical attention should be sought.

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