I’m taking a statin drug for my cholesterol. Will a genetic test tell me whether I’ll have side-effects?

August 22, 2016

Genetic testing that can detect the risk of medication side-effects is called “pharmacogenomics” – a brand-new field in pharmacy. The goal of pharmacogenomics is to answer the question: Does the patient have certain genetic mutations that are known to influence their response to a drug in a certain way? Ideally, pharmacogenomics helps predict who will benefit from a medication, who will not respond at all, and who will experience negative side effects.

You ask about statins. A common side-effect of statin drugs is “myalgia” – muscle soreness or pain (similar to the muscle achiness felt when you have the flu). But most reports of myalgia are not linked to any actual muscle tissue damage, and severe muscle side effects involving muscle tissue damage are very rare.

There has been a lot research around the side-effects of statins and understanding how genetic risk factors influence statin-induced muscle-related side-effects. Recent data has shown that certain genetic variations do impact how statins work. For example, there’s strong evidence that people who have a specific genetic mutation are more likely to experience myalgia when taking a specific drug at a high dose, but that drug/dose combination is seldom used today. For all other statins (including the one you’re likely taking), the evidence available concludes that most patients with the mutation don’t develop symptoms, so genetic testing to predict myopathy isn’t recommended.

And keep in mind that genetic risk is only one of many factors that influence your risk of side-effects. Many other factors influence how you’ll respond to a statin, such as age, gender, ethnicity, body size, pre-existing illnesses like thyroid or kidney disease, alcohol use, drug interactions, as well as the statin dose you’re taking. Working closely with your pharmacist to understand and manage your own risk factors, such as how to avoid drug interactions, is the best way to reduce the risk of statin side-effects, including myalgia.

While research currently available hasn’t shown genetic testing for statin side-effects to be very useful, there are situations where knowing whether a person has a particular genetic mutation is valuable in determining effective treatment. For instance, the genetic makeup of breast cancer patients can help doctors choose the most appropriate chemotherapy, and HIV-positive patients are tested for a certain gene mutation that can result in serious reactions with a specific drug.

It’s still early days for pharmacogenomics, but as more research is done that demonstrates its value, genetic testing in specific situations will likely become more routine when choosing drug treatment options in future.