SLCO1B1 Gene: How It Affects Drug Response and Safety

When your body breaks down certain medications, the SLCO1B1 gene, a gene that codes for a protein responsible for transporting drugs into the liver. Also known as SLC01B1, it plays a key role in how safely and effectively drugs like statins, methotrexate, and some HIV meds work in your system. If you have a common variation in this gene, your liver might not clear these drugs the way it should—leading to higher drug levels in your blood and a bigger risk of side effects.

This isn’t theoretical. Studies show people with a specific SLCO1B1 variant (called rs4149056) are up to four times more likely to get severe muscle pain from statins like simvastatin. That’s not a rare fluke—it’s a well-documented genetic pattern. And it’s not just about statins. The same gene affects how your body handles drugs like repaglinide for diabetes and some antivirals used in HIV treatment. If you’ve ever been told to stop a medication because of side effects, only to find out later that it worked fine for someone else, your SLCO1B1 gene might be why.

The good news? You don’t need to guess. Genetic testing for SLCO1B1 is available and increasingly used in clinics to guide prescribing. If you’re on long-term medication, especially for cholesterol, diabetes, or HIV, knowing your SLCO1B1 status can help avoid unnecessary side effects and find the right dose faster. It’s not about changing your genes—it’s about adjusting your treatment to fit them.

Below, you’ll find real-world guides on how this gene connects to drug safety, what to ask your doctor, and how to interpret test results. Whether you’re managing statin side effects, wondering why a medication didn’t work for you, or just curious about how your body handles drugs, these posts give you the facts—not the hype.