Acetaminophen
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Taken as tablets, capsules, or liquid. The most important rule is the daily limit, because too much can seriously damage the liver. Acetaminophen is also hidden in many cold, flu, and combination pain products, so add those up too.
- Pain relief (adjunct): 325 to 650 mg every 4 to 6 hours, or 1000 mg every 6 to 8 hours, without going over the daily limit.
It usually works within 30 to 60 minutes.
Tests while you take it
No routine blood tests are needed at normal doses. Never combine it with other products that also contain acetaminophen, and get urgent medical care for any suspected overdose even if you feel fine.
What to know
How it is used in arthritis
In osteoarthritis, acetaminophen may help a little with pain and can be used if anti-inflammatories are not suitable, but studies show the benefit is small, so it is usually an add-on rather than the main treatment. In spine-related arthritis (axial spondyloarthritis) it does not treat the underlying inflammation, so it is used only for extra pain relief, not as a main medicine.
Monitoring
No routine blood tests are needed at normal doses. The main thing is to stay within the daily limit.
Common effects
At normal doses, side effects are uncommon. The main danger is liver harm from taking too much.
Important cautions
Take extra care, and use a lower daily limit, if you have liver problems, drink alcohol regularly, or are underweight. Always check other medicines for hidden acetaminophen.
What to watch for
- Signs of liver trouble such as yellowing of the skin or eyes, dark urine, or pain in the upper right belly.
- Any suspected overdose, even if you feel well (get urgent care).
- A rash or allergic reaction after taking it.