The Bottom Line

• Osteoarthritis is one of the top causes of disability worldwide.  
• Tylenol, also commonly known as acetaminophen or paracetamol, is often the first treatment option tried for knee and hip osteoarthritis. 
• In people with knee or hip osteoarthritis, Tylenol provides marginal improvements in pain (immediately/short-term) and physical function (short-term), but not likely to a degree that makes a meaningful impact.
• Overall, Tylenol does not increase the risk of negative side effects. 
• Other potentially effective treatment options for osteoarthritis include: non‐steroidal anti‐inflammatory drugs (NSAIDs), exercise, acupuncture, and surgery.
• Start a discussion with your health care provider about the risks and benefits of different treatment options for knee and hip osteoarthritis. 

What’s in a name?
Acetaminophen, paracetamol, Tylenol… The use of these terms interchangeably can leave us getting Shakespearean and asking, what’s in a name? In this case, the answer is nothing. These three names all refer to the same medication, the only difference being that Tylenol is a brand name, while acetaminophen and paracetamol are generic names.

Tylenol is a common fixture in many of our medicine cabinets. It’s one of our go-to methods for relief from fevers, and all sorts of aches and pains. One particular kind of pain that has us opening those cabinet doors is arthritis pain (1). Over 4.7 million Canadians aged 50 years and older live with arthritis (2). When it comes to the top contributors of disability worldwide (1;3), osteoarthritis—the most common type of arthritis (4;5)—makes the list (3). Because osteoarthritis pain hinders our ability to move and function well physically (1), managing it is an important goal for both patients and doctors.

Hip and knee joints
Joints that carry our weight (4), such as the knees and hips, are locations that often bare the negative consequences of osteoarthritis (3;6). But just what is the first treatment option most often recommend for treating knee and hip osteoarthritis pain? You guessed it…Tylenol (1;7-8). Interestingly, as the evidence-base on the use of Tylenol grows, so does the debate around its use for treating knee and hip osteoarthritis. In particular, issues around how effective and safe this treatment option is are being raised (1;9-11).

What the research tells us

A recent systematic review comparing the use of paracetamol (a.k.a. acetaminophen or Tylenol) versus placebo for treating knee and hip osteoarthritis reported several interesting findings.

First and foremost, when it comes to pain, in both the immediate term (two weeks or less) and short-term (more than two weeks but three months or less), Tylenol only provides marginal improvements. Second, while Tylenol most likely does not enhance physical function immediately, it does provide small improvements in the short-term. With that said, in all instances where benefits were seen, the size of the difference was so small that the authors concluded that taking Tylenol daily likely would not make a meaningful impact on the lives of folks with knee and hip osteoarthritis in the immediate term or short-term.

What about the potential for negative side effects?

Overall, people with knee and hip osteoarthritis taking Tylenol do not appear to have a higher chance of experiencing negative side effects. Also worth mentioning, is that the risk of an abnormal liver function test—which relates to liver toxicity—may increase with Tylenol use. But this finding lacks certainty because of the reliability of the evidence. Remember, in terms of safety, always use medications as instructed by the package or a pharmacist, or as prescribed by a health care provider.

Daily use of Tylenol needs re-consideration
Taking into consideration both the findings on the limited benefits and the potential for harms, the authors of the review call for the use of Tylenol as the first-treatment option for people with knee or hip osteoarthritis to be reevaluated (1).

This might leave some wondering, if not Tylenol than what?

Doctors will often recommend over-the-counter non‐steroidal anti‐inflammatory drugs (NSAIDs)—such as celecoxib , diclofenac, ibuprofen, and naproxen—when Tylenol is not cutting it (1;12-14). Evidence shows that oral NSAIDs—specifically diclofenac, ibuprofen, and naproxen—are more effective in reducing pain than Tylenol in people with knee osteoarthritis. Oral NSAIDs can also be more effective than Tylenol in improving both physical functioning and reducing stiffness (14). Despite this, Tylenol is often used as a first-line treatment because it‘s seen as being a safer option (1). For instance, NSAIDs may come with an increased risk of heart attack and/gastrointestinal issues (14;15). More research comparing the safety of these treatment options is needed (14).

Non-drug options for dealing with knee or hip osteoarthritis
Non-drug options for dealing with knee or hip osteoarthritis—including exercise, acupuncture, and surgery—can also be effective. Click on the links below for more information on these strategies:

• Bad knees? The right kinds of exercise can bring pain relief and improve balance
• Painful knees? What about acupuncture?
• Mini-incision hip replacement surgery: Is it right for you?

All in all, these results do not mean you should be eager to stop a treatment recommended by your health care provider or start a new one they have not recommended. Instead, open a discussion about the different drug and non-drug treatment options available and the pros and cons of each for you.

Consult with your doctor regarding health issues.