Drugs that are marketed without a prescription are generally thought to be safe and effective. To keep them so, careful attention must be paid to dosages. The “how much” and the “how often” matter a great deal. The normal adult dose for acetaminophen (Tylenol) isn’t harmful – up to eight 500mg tablets in a 24 hour period.
Unfortunately, some patients will exceed this dose. It can happen in a few different ways, but usually with combination medications, like Tylenol with codeine. Patients who legitimately receive these for pain may not realize they cannot simply increase the dose without bounds. This is especially true when the pills are labeled, “Take as needed for pain.” As they try to manage their pain by taking more codeine, they are also taking more acetaminophen as a consequence.
In accidental overdose situations, patients may be unaware that some combination of medications is providing too much Tylenol. Acetaminophen is commonly found, not only in over the counter pain medications, but also fever reducers, flu medicines and cough/cold preparations. Since someone may take several of these for different problems at the same time, they may get too much acetaminophen in total. Four thousand milligrams is considered safe – however that amount is reached.
Another path to liver damage comes when an addict is getting acetaminophen and codeine tablets illegally. To get a better experience, they may take more than the maximum daily dose and do it for an extended period of time. Their bodies become tolerant to the effects of the codeine in the medication but not to the ever increasing amount of Tylenol they get along with the opiate.
Liver damage occurs because it is the site where acetaminophen is converted into other metabolites that are then excreted. Normal and safe amounts are handled well. But when the amount the liver has to process exceeds its ability, toxic substances are formed in the liver. The cells nearby are damaged from this alternative type of metabolism.
Some drugs will also limit the liver’s ability to detoxify acetaminophen, and a severe lack of sulfur in the diet will do so as well. There is also a genetic component. Just through random genetic chance, some people will be able to metabolize more acetaminophen than others.
The general rule is to stick with the dosage prescribed by a physician. If the amount you are supposed to take exceeds the safe daily dose, see if your doctor will prescribe a stronger pain medication. And make sure you read ingredient labels for any other medications you may want to take.
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