OTC Pain Relievers and Fever Reducers (cont.)

Pharmacy Author:
Medical Editor:

Drug interactions and aspirin

Aspirin may interact with other medications and cause undesirable side effects. For example, high doses of aspirin can increase the activity of valproic acid (Depakene; Depakote), an effect which can cause drowsiness or behavioral changes.

High doses of aspirin also can enhance the effect of some blood sugar-lowering medications used to treat diabetes, including glyburide (Diabeta), glipizide (Glucotrol), and tolbutamide (Orinase), which can possibly lead to hypoglycemia (low blood sugar). Blood sugar levels may need to be more closely monitored in this setting.

Aspirin, when taken together with an anti-coagulant such as warfarin (Coumadin) or enoxaparin (Lovenox), can greatly impair the body's ability to form blood clots, resulting in excessive bleeding spontaneously, from ulcers, or related to a procedure. Therefore, patients on such combinations must be closely monitored by a doctor.

Low dose aspirin can raise levels of uric acid in the blood and may need to be avoided in patients with increased uric acid levels or gout.

Certain NSAIDs, particularly ibuprofen (Motrin, Advil), if taken just before aspirin or in multiples doses each day, can reduce the anti-platelet effects of aspirin treatment and theoretically render aspirin less effective in preventing heart attacks and ischemic strokes.

Salicylates other than aspirin

Choline salicylate (Arthropan) is available as a liquid. It is absorbed more quickly, but its onset of action is no different than that of aspirin. Some people find choline salicylate fishy tasting. Fortunately, it can be mixed with juice or soda prior to ingestion. It is less effective at reducing fevers in children than either aspirin or acetaminophen.

Magnesium salicylate (Arthriten; Backache) is as effective as aspirin at reducing pain. Patients with chronic kidney disease should avoid magnesium salicylate, since the magnesium may accumulate in the body.

Sodium salicylate (Scot-Tussin Original) and aspirin are equally effective in the long-term treatment of rheumatoid arthritis, but sodium salicylate is less effective at reducing pain or fever.


Acetaminophen comes in various oral formulations, including different types (elixirs or syrups) and flavors of liquids, capsules, tablets, caplets, and suppositories. The capsules contain tasteless granules that can be emptied onto a teaspoon containing a small amount of drink or soft food, and can then be swallowed. However, the granules should not be mixed in a glass of liquid since the granules will stick to glass itself. The amount of acetaminophen that is absorbed from rectal suppositories is about half that of the oral formulations.

Side effects of acetaminophen

Acetaminophen generally is safe to use, and few people develop side effects. In high doses, however, it can cause liver damage and doses of 4000 mg (4 grams) per day should not be exceeded.

Pregnancy/breastfeeding and acetaminophen

Acetaminophen has no known harmful effects on the mother, fetus, or infant and, therefore, can be used safely during pregnancy and breastfeeding.

Drug interactions and acetaminophen

It has been reported that patients with HIV-related diseases (such as AIDS) who take AZT (zidovudine; Retrovir) and acetaminophen are at an increased risk of developing suppression of their bone marrow. Such patients develop lower white and red blood cell and platelet counts and, therefore, are more susceptible to infection, anemia, and bleeding.

Nonsteroidal Anti-inflammatory Drugs (NSAIDS)

There are three OTC NSAIDs; ibuprofen, naproxen sodium, and ketoprofen. All have pain relieving (analgesic), fever reducing (antipyretic), and anti-inflammatory properties. Additionally, NSAIDs are more effective than aspirin or acetaminophen for menstrual cramps.

Preparations of NSAIDs

Ibuprofen is available in tablets as well as in a pediatric suspension. Naproxen sodium is available in tablets. Ketoprofen is available as tablets and capelets.

Side effects and NSAIDs

The most frequent side effect of NSAIDs is damage to the lining of the stomach and duodenum that can lead to abdominal pain, nausea, and loss of appetite. NSAIDs also can cause ulcers and bleeding from the stomach and duodenum, but less frequently and less severely than occurs with aspirin use. NSAIDs, like aspirin, affect platelets and can inhibit the formation of blood clots, and, therefore, they should be discontinued at least 3 days before surgery or dental procedures.

Report Problems to the Food and Drug Administration

You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.

Pill Finder Tool

Need help identifying pills and medications?
Use the pill identifier tool on RxList.

Back to Medications Index