When your doctor orders a blood test and sees AST, aspartate aminotransferase, a liver enzyme that leaks into the blood when liver cells are injured. Also known as SGOT, it's one of the first clues doctors use to check if your liver is under stress. It’s not a disease itself—but it’s a red flag. High AST doesn’t tell you why your liver is hurt, but it tells you something’s wrong. And when paired with another enzyme called ALT, it helps narrow down the cause: alcohol, medication, fatty liver, or even a virus.
Many of the medications covered in our posts—like clozapine, an antipsychotic known to cause liver enzyme spikes, or tolvaptan, a kidney-focused drug that can affect liver function, or even common painkillers like acetaminophen—require regular liver function tests, blood panels that track enzymes like AST and ALT to catch harm before it’s serious. That’s why lab monitoring calendars are so important. If you’re on long-term meds, your AST levels might be tracked every few weeks. A sudden jump could mean it’s time to adjust your dose—or stop the drug entirely. Seniors, in particular, are more vulnerable. Their livers process drugs slower, and polypharmacy increases the risk. That’s why deprescribing isn’t just about cutting pills—it’s about protecting organs like the liver from silent damage.
AST isn’t just about the liver, though. It’s also found in the heart, muscles, and kidneys. That’s why a high AST alone isn’t enough. If your AST is high but ALT is normal, it might point to muscle damage or a heart issue—not liver disease. Doctors always look at the full picture: the AST/ALT ratio, bilirubin, albumin, and how you feel. If you’ve ever had a bad reaction to antibiotics like metronidazole or secnidazole, or noticed unexplained fatigue after starting a new drug, your AST might have been the first sign. Monitoring isn’t just paperwork—it’s prevention. And with new FDA guidelines pushing for clearer medication labels, you’re more empowered than ever to ask: "Is my AST being checked? Why? What does it mean?" Below, you’ll find real-world guides on how medications affect liver enzymes, when to push back on unnecessary tests, and how to track your own liver health without waiting for a crisis.
Liver function tests like ALT, AST, and bilirubin don't measure liver function-they reveal damage. Learn how to interpret these results, what patterns mean, and when to take action for real liver health.
