Effects of Liver Disorders on Drugs

Liver disorders often change the effect of drugs on the body—for example, by changing

(See also Drugs and the Liver Drugs and the Liver The body must process (chemically alter, or metabolize) drugs to be able to use and eliminate them. Most of this processing occurs in the liver, done by liver enzymes. Thus, drugs and the liver... read more .)

How liver disorders affect a drug depends on the particular drug. Liver disorders can increase the effects of some drugs and decrease the effects of others. The drug's effect is increased if the liver is less able to inactivate a drug. The drug's effect is decreased if the liver is less able to change the drug to an active form or if the liver makes the body less able to absorb a drug or to transport it throughout the body.

A chronic liver disorder can make people more sensitive to the effects of certain drugs, even when the disorder does not increase the amount of drug in the body. For example, if people with certain liver disorders take even small doses of opioid pain relievers Opioid Pain Relievers Pain relievers (analgesics) are the main drugs used to treat pain. Doctors choose a pain reliever based on the type and duration of pain and on the drug's likely benefits and risks. Most pain... read more (such as morphine) or sedatives Misuse of Antianxiety Medications and Sedatives Antianxiety and sedative medications are prescription drugs used to relieve anxiety and/or help with sleep, but their use can result in dependency and a substance use disorder. Using prescription... read more (such as lorazepam), mental function may deteriorate, and they may become confused, disoriented, and less alert. Mental function deteriorates, probably because the liver disorder makes the brain more sensitive to the effects of these drugs.

Because liver disorders are complicated, doctors often cannot predict how they will affect a particular drug. Thus, adjusting drug doses for people who have a liver disorder can be difficult.