I’ve heard that Tylenol is dangerous for the liver. Is this true, and are there any medications I need to avoid?

Almost all oral medications are absorbed into the bloodstream and carried immediately to the liver for processing. It is therefore important to avoid medications that can cause liver damage. Most prescription medications are safe for the liver, although some require a reduction in dose for patients with liver disease. If you have any questions about the safety of a new medication you have been prescribed, you should discuss your concerns with the prescribing physician and/or a member of the transplant team. Several commonly prescribed medications are worthy of specific mention in conjunction with liver disease.

Acetaminophen (Tylenol)

Acetaminophen is a medication that is available in both prescription strength and as an over-the-counter (OTC) drug. Acetaminophen is commonly combined with other pain medications such as oxycodone (Percocet), hydromorphone (Vicodin), and Darvocet. It is also found in many flu, cold, and headache preparations. Contrary to popular belief, acetaminophen can be taken safely by patients with liver disease, as long as they adhere to some limitations.

When swallowed, acetaminophen is absorbed into the blood and normally broken down into two parts: the part that controls flu and headache symptoms and a substance that is toxic to the liver. Fortunately, a detoxifier, called glutathione, is waiting for the toxin to arrive in the liver. Glutathione is rapidly, but not instantaneously, reproduced by the liver. The damaged liver may have a slower rate of glutathione production but nonetheless has a replenishable supply. Acetaminophen in doses up to 2,000 milligrams per 24 hours can be effectively detoxified even by the cirrhotic liver. It is important to note that acetaminophen does not slowly damage the liver and that it cannot cause cirrhosis. Because acetaminophen is found in many common medications, you should recognize that the total daily dose may come from different sources of acetaminophen.

Cholesterol-Lowering Agents

Cholesterol control has improved dramatically since the introduction of the cholesterol-lowering agents known as statins. One of the side effects of this class of drugs is liver cell toxicity, although this problem occurs in only a minority of patients. For patients with liver disease these drugs can be used with caution. First, however, you should determine whether a reduction in your cholesterol level is required. Lowering your cholesterol level reduces your risk of stroke and heart attack over the course of many years. For most patients with advanced liver disease this may not be a priority, so use of the statins can be avoided until after transplantation. Other patients may have a strong family history of coronary artery disease and stroke or may have had a heart attack themselves; in this group the statins may be necessary therapy. If a potentially liver-toxic drug is deemed to be of benefit to a particular patient, levels of the liver enzymes can be followed closely to confirm that liver toxicity is not occurring. These tests should be performed several times over the first 3 months of prescription use and then periodically thereafter. If the enzyme levels rise significantly above the baseline and remain high, the medication should be stopped.

Psychiatric Medications

Like the cholesterol-lowering agents, many psychiatric medications—but particularly the older ones—have the potential to cause liver damage. This effect occurs only rarely with use of the newer selective serotonin reuptake inhibitors such as Prozac, Paxil, and Celexa. Again, if a potentially liver-toxic drug is deemed to be of benefit to a particular patient, the liver enzyme levels can be followed closely to rule out liver toxicity. These tests should be performed several times over the first 3 months of prescription use and then periodically thereafter. If the enzyme levels rise significantly above the baseline and remain high, the medication should be stopped.