Acetaminophen (Tylenol)

Acetominophen (Tylenol) is a mild analgesic and is often the first choice in pain control because it is inexpensive and carries minimal side effects.  It does not cause GI/stomach irritation, as do many NSAIDs (see below). The maximum daily dosage is 4,000mg (1,000mg 4 times per day). Tylenol is not an option for patients with liver disease, patients who abuse alcohol, and should be taken with caution if on Coumadin.1

A 2009 literature review by Towheed et al compared 7 randomized controlled trials of acetaminophen versus placebo, and 10 trials comparing acetaminophen to NSAIDs for efficacy and safety.  The studies comparing Tylenol and the placebo found Tylenol to be more effective in pain reduction than the placebo, however it only improved pain levels by 5%. The two groups appeared to be equally safe.
In the studies comparing NSAIDs and Tylenol, the NSAIDs were more effective at pain reduction, global assessments, and return to function. Although the drugs rated similar in safety, the NSAIDs had more adverse GI reactions.2

A 2003 study by Case, et al, found Tylenol to be ineffective as treatment for knee OA. The study used the WOMAC pain score at two and twelve weeks post-treatment. Tylenol was compared to a placebo and diclofenac (Voltaren); the diclofenac was the only group that showed clinically and statistically significant improvements.3