Many medications can cause liver enzymes to be elevated.

A familiar over-the-counter medication that can cause liver damage from an overdose is acetaminophen (Tylenol). A healthy person should not take more than 3,000 to 4,000 milligrams in a single day. This maximum dose range may not be safe if you drink alcohol or have liver disease.

Another class of medications that sometimes causes liver enzymes to rise are cholesterol lowering medications, called statins. Statins include the medications simvastatin, atorvastatin, pravastatin and lovastatin. Statins rarely cause liver damage, and doctors no longer check liver enzymes for people on statins routinely.

Other common medications that may cause elevated liver enzymes include:

• The antibiotics synthetic penicillin, ciprofloxacin and tetracycline
• The anti-seizure drugs carbamazepine and phenytoin and valproic acid
• Nonsteroidal anti-inflammatory drugs (NSAIDs)
• The diabetes drugs sulfonylureas and glipizide
• The tuberculosis drugs isoniazid, pyrazinamide and rifampin
• The antifungal drug ketoconazole
• The antidepressant fluoxetine
• The antipsychotic risperidone
• The antiviral drugs valacyclovir and ritonavir
• The rheumatoid arthritis drug methotrexate
• Abused drugs such as alcohol, cocaine and anabolic steroids
• The herbal medications chaparral, comfrey tea, kava, skullcap, yohimbe, ji bu huan and ephedra

As part of the Food and Drug Administration (FDA) approval process, medications are screened for their potential to cause liver damage. In most cases, you will not get liver damage if you take these drugs as prescribed. Damage may occur if you are sensitive to the drug, if you take more than prescribed or if you already have a liver condition.

Herbal medications are not tested by the FDA. If you have liver disease, check with your doctor before taking any new medications or supplements.

Liver enzymes

Liver enzymes are proteins your liver uses for normal liver functions. When your liver is damaged, these enzymes leak out into your blood and can be measured with blood testing called liver function testing.

There are several liver enzymes, but the ones that show liver damage from medications are aspartate transaminase (AST) and alanine transaminase (ALT). Medications may cause liver enzymes to be elevated without serious liver damage until they reach 3 to 5 times the normal levels.