FEATURES OF ACETAMINOPHEN

Acetaminophen is widely used alone (Rx: 1000mg/day, 4x/day), and is approved for osteoarthritis but NOT for rheumatoid arthritis because it is a very weak COX-1, COX-2 inhibitor. We don’t know its precise activity, but we do know that it has no clinically significant anti-inflammatory properties. It DOES have anti-fever and anti-headache properties, and is an effective analgesic.


When you take med history of pt, be sure to take the regimen and dose that the pt is taking! There is a dose-limit! DO NOT EXCEED 4 GM/DAY, UP TO 10 DAYS, IN MANAGING ACUTE PAIN. FOR LONG TERM THERAPY, DO NOT EXCEED 2.6 GRAMS/ DAY. The reason for this warning is that severe liver toxicity may occur with prolonged use at high doses. So do not exceed the recommended dose! When acetaminophen is taken concurrently with alcohol, the drug toxicity is enhanced. So you must warn your patients NOT to drink alcohol because of its synergistic effects with acetaminophen.


Acetaminophen can be combined with codeine and related narcotics, caffeine (which accentuates many peripheral acting agents) and aspirin in fixed combination products (ie. Excedrin migraine tablets, available otc). Acetaminophen is contraindicated in active alcoholics, those with viral hepatitis and those with hepatic disease. If a person is allergic to one NSAID (aspirin or motrin) then they are allergic to all of them, prescribe acetaminophen instead.

Category: Pharmacology Notes