Two patients with depression each take the same dose of the same medication. One patient’s medication makes her feel extremely nauseous, leaves her with no energy and does not alleviate the symptoms of her depression. The other patient has no side effects and her medication works as prescribed. How can this be? The answer may lie in a patient’s genes.

Genes map what makes us unique. According to the Genetic Alliance, genes explain:

• Why family members’ appearances are similar
• How families’ health history can be passed down for generations, including some diseases like cancer

Genes also play an important role in how our bodies metabolize certain medications, such as antidepressants.

How Genes Impact Metabolism

Our unique genetic profile contains six enzymes that metabolize 90 percent of all medications patients are given.

These genes and enzymes help determine our individual rate of metabolism, which varies from person to person. Depending on your genetic profile, you may process some medications too quickly, or others, too slowly, which can both cause complications.

Research has found that people fall into one of four general metabolizer types.

The Four Metabolizer Types

1. Poor Metabolizer: Medication is broken down very slowly. May experience side effects at standard doses.
2. Intermediate Metabolizer: Slow rate of metabolism. May have too much medication at standard doses, potentially causing side effects.
3. Extensive Metabolizer: Normal rate of metabolism. Has normal amount of medication at standard doses.
4. Ultrarapid Metabolizer: Medication is rapidly broken down. Medication may be removed from a patient’s system too quickly to provide symptom relief.

Giving Your Doctor Information

Administered by your physician, a genetic test can give your doctor information about how your body processes certain medications based on your genetic metabolism rate.

According to Mayo Clinic: “Pharmacogenomic tests look for changes or variants in genes that may determine whether a medication could be an effective treatment for you or whether you could have side effects to a specific medication.”

• Clinicians can use genetic tests to:
  • analyze how genes may affect outcomes with medications
  • learn which medications may require dose adjustments
  • understand which medications may be less likely to work or may have an increased risk of side effects based on genetic makeup