Many people believe that anything available over-the-counter is automatically safe, but all medications have their risks. Acetaminophen is a very safe drug, yet excessive amounts are still dangerous.
Acetaminophen and Liver Damage
In appropriate doses acetaminophen is a very safe drug , as long as it is not combined with alcohol. The problems arise when either taking an overdose or large doses in the long-term. Both of these can lead to liver damage.
Acetaminophen is in fact the leading cause of acute liver failure. There are about 450 yearly deaths from acetaminophen overdose in the United States, about half of them unintentional. Some lucky ones are saved by quick liver transplants.
Safety Issues
The maximum recommended daily dose of acetaminophen for an adult used to be four grams (4,000 mg), but the FDA is planning to revise it down. 4,000 mg corresponds to about a dozen normal strength Tylenols (325 mg) or four extra-strength ones (1,000 mg), but what many people don't realize is that opiate painkillers and cold medications often also contain acetaminophen, making it easy to exceed the maximum daily dose.
If you are taking painkillers for a chronic condition, you should check that you are not taking too much acetaminophen. Besides acetaminophen, it may also be listed under the name "APAP". If you are worried about your acetaminophen intake, you should ask your doctor for advice. Those with liver problems or taking drugs that also affect the liver should avoid large doses of acetaminophen.
If you have accidentally or intentionally taken a large dose of acetaminophen, you should go to the hospital immediately. The effects of an overdose may not appear for quite some time, but after they do, it may be too late for the antidote.
Remember to keep acetaminophen and all other drugs out of the reach of children! If you are giving medication to a child, double check the strength of the preparation, as different children's preparations can contain very different amounts of medication.
Reducing the Risk of Liver Damage
If you have to take large doses of acetaminophen (paracetamol) in the long run, there are some things you can do to reduce the risk of liver toxicity. It is important to avoid excessive consumption of alcohol. Even moderate consumption of alcohol greatly increases the risk of liver damage with acetaminophen.
Another safety measure is taking N-acetylcysteine, which is available as a supplement in the U.S. and many other countries. It is also used as an antidote in acute acetaminophen overdose. N-acetylcysteine has been suggested as an addition to all acetaminophen pills, but manufacturers have turned the idea down for cost reasons.
There are several herbs that have been shown to reduce the risk of liver damage from acetaminophen. One of them is milk thistle (silymarin), which is well known for its liver-protecting properties.
Acetaminophen vs. Other Painkillers
So are NSAIDs a safer choice? Non-steroidal anti-inflammatory drugs (NSAIDs) like aspirin, naproxen and ibuprofen have a different set of problems attached to them. In long-term use even moderate doses can cause severe health issues, especially stomach ulcers and kidney problems.
Kidney problems sometimes cause edema (swelling), but stomach ulcers may not cause any symptoms until a very late stage. The newer COX-2 specific NSAIDs like celecoxib (Celebrex) reduce the risk of stomach ulcers, but large doses still damage the lining of the stomach. Acetaminophen has a very low risk of causing stomach damage.
It should be kept in mind that acetaminophen is a very safe drug when taken properly, but most people are not aware of the risks of taking large doses. All medications have some risks which have to be weighed with the benefits of taking them.
References
The New York Times: Warnings Proposed for Over-the-Counter Drugs (12/20/2006)
Muriel P, Garciapiña T, Perez-Alvarez V, et al. Silymarin protects against paracetamol-induced lipid peroxidation and liver damage. J Appl Toxicol. 1992 Dec;12(6):439-42.
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