Dozens of commonly prescribed medications can raise ALT levels, the liver enzyme your doctor measures to check for liver cell damage. Antibiotics are the most frequent culprits, but pain relievers, cholesterol drugs, supplements, and several other drug classes can do it too. Normal ALT falls between 7 and 55 U/L for men and 7 and 45 U/L for women, and doctors typically flag an elevation as significant when it rises above three times the upper limit of normal.
Antibiotics Are the Most Common Cause
Across three large international studies tracking drug-induced liver injury, one antibiotic stood out above all others: amoxicillin-clavulanate, sold as Augmentin. It accounted for 10 to 22% of all drug-induced liver injury cases depending on the study. The injury typically appears within four weeks of starting the medication, though it sometimes shows up only after you’ve already finished the course. Most people recover within 16 weeks of stopping.
Other antibiotics that frequently raise ALT include isoniazid (used for tuberculosis), nitrofurantoin (used for urinary tract infections), trimethoprim-sulfamethoxazole (Bactrim), minocycline, azithromycin, ciprofloxacin, and doxycycline. Isoniazid is particularly notable because it often causes a temporary, asymptomatic bump in liver enzymes early in treatment that resolves on its own. In severe cases, though, ALT can spike above 10 times the upper limit of normal with symptoms of hepatitis.
Flucloxacillin and erythromycin round out the list of antibiotics most often linked to liver problems. Flucloxacillin-related injury can appear anywhere from one to nine weeks after starting the drug, and about 30% of affected patients have a prolonged course of recovery.
Acetaminophen (Tylenol)
Acetaminophen is one of the best-known causes of liver injury, and it can raise ALT even at recommended doses. In a controlled study of healthy adults taking 4 grams per day (the maximum labeled dose), some participants developed ALT elevations above three times normal. Those elevations didn’t appear before day three of use. After the medication was stopped, ALT continued climbing for up to four more days before peaking, and it took a median of 6.5 days to drop back below the danger threshold.
At higher-than-recommended doses, acetaminophen causes direct, predictable liver cell destruction. This makes it different from most other drugs on this list, where liver injury is unpredictable and happens only in certain individuals.
NSAIDs and Other Pain Relievers
Non-steroidal anti-inflammatory drugs as a class cause mild ALT and AST elevations in 5 to 15% of people who take them. Most of these elevations are small and don’t cause symptoms. Ibuprofen, diclofenac, and aspirin are the most commonly used NSAIDs linked to liver enzyme changes. Diclofenac appeared among the top causes of drug-induced liver injury in both the Spanish and Icelandic registries tracking these cases.
Several older NSAIDs were actually pulled from the market because of severe liver toxicity. The withdrawal of benoxaprofen in 1982 after reports of fatal jaundice in the United Kingdom was a turning point that focused serious attention on NSAID-related liver damage.
Statins (Cholesterol Medications)
About 3% of people taking statins develop elevated ALT levels. The chance of a significant elevation, above three times normal, ranges from 0.5 to 3% and increases with higher doses. These elevations mostly appear in the first three months of therapy and are usually temporary, resolving even if you continue taking the medication.
Atorvastatin, simvastatin, and fluvastatin have all appeared in liver injury registries, though serious statin-related liver damage is rare. The FDA no longer recommends routine liver enzyme monitoring for people on statins. Instead, testing is advised at baseline and then only if symptoms develop. If you notice unusual fatigue, dark urine, or yellowing of the skin while on a statin, that warrants prompt evaluation.
Methotrexate and Immune-Suppressing Drugs
Methotrexate, widely prescribed for rheumatoid arthritis and psoriasis, causes mild ALT elevations that are usually self-limited. The bigger concern is long-term use, which can lead to fatty liver, fibrosis, and eventually cirrhosis with cumulative exposure. This is why patients on methotrexate typically have their liver enzymes checked regularly throughout treatment.
Azathioprine, another immune-suppressing medication used in autoimmune conditions and after organ transplants, also appears in liver injury registries. Newer immune checkpoint inhibitors used in cancer treatment frequently cause asymptomatic liver enzyme elevations early in treatment, with a pattern that’s primarily hepatocellular.
Antidepressants and Psychiatric Medications
Several commonly prescribed psychiatric medications can cause hepatocellular injury and elevated ALT. These include fluoxetine (Prozac), sertraline (Zoloft), paroxetine (Paxil), trazodone, bupropion (Wellbutrin), and risperidone. Valproate, an anti-seizure and mood-stabilizing drug, is also well documented as a cause of liver enzyme elevation. The risk varies widely between individuals, and for most of these drugs, clinically significant liver injury is uncommon relative to how often they’re prescribed.
Other Prescription Medications
Several other drug classes round out the list of ALT-raising medications:
- Blood pressure drugs: Lisinopril and losartan can both cause hepatocellular injury.
- Heart rhythm drugs: Amiodarone is a well-known cause of liver enzyme elevation.
- Antifungals: Ketoconazole carries enough liver risk that oral formulations have been restricted in several countries.
- Antiretrovirals: Drugs used to treat HIV can elevate ALT, requiring ongoing monitoring.
- Acne medication: Isotretinoin (Accutane) appeared among the top causes in the Icelandic liver injury study.
- Acid reflux drugs: Omeprazole has been linked to hepatocellular injury, though rarely.
- Gout medication: Allopurinol can cause ALT elevations.
Herbal Supplements and Vitamins
Herbal and dietary supplements account for roughly 16% of all drug-induced liver injury cases, a number that surprises many people who assume “natural” products are inherently safe. Bodybuilding supplements are the single largest category, often because they’re contaminated with undisclosed anabolic steroids that damage liver cells directly.
Weight loss products carry particular risk. Hydroxycut, Herbalife products, and OxyELITE Pro have all been linked to severe liver injury, including acute liver failure. Green tea extract in concentrated supplement form (not regular brewed tea) is a documented cause of hepatocellular damage. Usnic acid, an ingredient in some fat-burning supplements, is toxic enough that products containing it have been pulled from shelves.
Other supplements with established links to liver injury include kava, black cohosh, kratom, high-dose vitamin A, ashwagandha, turmeric (especially newer high-absorption formulations that use piperine or nanoparticles to boost curcumin levels), and comfrey. Traditional Chinese medicine preparations, particularly those containing Polygonum multiflorum, have also been implicated. The challenge with supplements is that they’re not regulated the same way as prescription drugs, so contamination and mislabeling are common.
How Liver Injury Develops
ALT is an enzyme that lives inside liver cells. When those cells are damaged or destroyed, ALT leaks into the bloodstream, and your levels go up. The pattern of injury matters for identifying the cause. Most of the medications listed above cause what’s called hepatocellular injury, meaning they damage liver cells directly. This shows up as a prominent ALT elevation. Some drugs, like amoxicillin-clavulanate and erythromycin, instead cause cholestatic injury, where bile flow is blocked, which raises a different set of liver markers more prominently.
Drug-induced liver injury can be dose-dependent (predictable, like acetaminophen) or idiosyncratic (unpredictable, affecting only certain people regardless of dose). Most prescription medications cause the idiosyncratic type, which is why routine liver monitoring catches some people off guard. The timing varies too. Some drugs raise ALT within days, while others take weeks or even months. Statins typically cause changes in the first 12 weeks. Amoxicillin-clavulanate can cause delayed injury that shows up after you’ve already finished your prescription.
What Elevated ALT Levels Mean in Practice
Not every medication-related ALT bump is dangerous. Many drugs cause mild, temporary elevations that resolve without stopping the medication. This is common with statins, isoniazid, and methotrexate. Doctors generally become concerned when ALT rises above three times the upper limit of normal, and more so when it’s accompanied by symptoms like fatigue, nausea, abdominal pain, dark urine, or yellowing of the skin or eyes.
If you’re on a medication and your ALT comes back high, the initial workup typically includes a hepatitis panel, iron studies, and an abdominal ultrasound to rule out other causes. Borderline or mild elevations often need nothing more than repeat testing. Moderate elevations may prompt additional investigation for autoimmune conditions. Severe elevations, especially with symptoms, usually lead to stopping the suspected drug and closer monitoring until levels normalize.