What if the GeneSight test shows no known genetic markers for certain medications, such as Selective Serotonin Reuptake Inhibitors (SSRIs) or Serotonin-Norepinephrine Reuptake Inhibitors (SNRIs), how should they be prescribed?

From the Guidelines

If the GeneSight test shows no known genetic markers for certain medications, such as Selective Serotonin Reuptake Inhibitors (SSRIs) or Serotonin-Norepinephrine Reuptake Inhibitors (SNRIs), clinicians should follow standard prescribing protocols based on symptom presentation, medical history, and clinical guidelines. When prescribing SSRIs or SNRIs, consider starting with a first-line SSRI such as sertraline (starting at 50mg daily) or escitalopram (starting at 10mg daily), as these typically have favorable side effect profiles and broad efficacy, as suggested by the Japanese Society of Anxiety and Related Disorders/Japanese Society of Neuropsychopharmacology 1. Some key points to consider when prescribing these medications include:

• Starting at the lower end of the dosing range and gradually titrating upward over 2-4 weeks as needed while monitoring for therapeutic response and side effects
• If the first medication trial is unsuccessful after an adequate duration (6-8 weeks at a therapeutic dose), consider switching to another SSRI/SNRI or augmenting with another agent
• Regular follow-up appointments (initially every 2-4 weeks) are essential to assess response, manage side effects, and adjust treatment accordingly The absence of genetic markers doesn't mean these medications won't be effective; it simply indicates that the patient doesn't have the specific genetic variations known to affect metabolism or response to these medications 1. Medication response involves multiple factors beyond genetics, including environmental influences, concurrent medications, and individual physiology. In the context of social anxiety disorder, the Japanese Society of Anxiety and Related Disorders/Japanese Society of Neuropsychopharmacology suggests SSRIs and venlafaxine, a serotonin-norepinephrine reuptake inhibitor (SNRI), as treatment options 1.

From the Research

GeneSight Test Results

• The GeneSight test reported no proven genetic markers for certain medications, such as Selective Serotonin Reuptake Inhibitors (SSRIs) or Serotonin-Norepinephrine Reuptake Inhibitors (SNRIs) 2.
• This means that the test did not identify any specific genetic variations that would affect how the patient responds to these medications.

Implications for Medication Prescription

• In the absence of genetic markers, healthcare providers may need to rely on other factors, such as medical history, symptoms, and trial-and-error, to determine the most effective medication and dosage for the patient 3.
• The selection of SSRIs or SNRIs may be based on their pharmacological profiles, efficacy, and tolerability, as well as the patient's individual needs and medical history 4, 5, 6.
• For example, venlafaxine, a SNRI, has a dose-dependent effect on blood pressure, and its use may need to be carefully monitored in patients with hypertension 4.
• Duloxetine, another SNRI, has a more balanced profile of binding to 5-HT and NE transporters and may be a suitable option for patients who do not respond to SSRIs 4.

Considerations for Treatment

• The choice of medication should be based on a comprehensive evaluation of the patient's condition, including their medical history, symptoms, and potential interactions with other medications 5.
• Healthcare providers should be aware of the potential advantages and disadvantages of each medication, including their efficacy, tolerability, and potential side effects 4, 6.
• The use of pharmacogenomic testing, such as the GeneSight test, may help guide medication selection, but its effectiveness is still uncertain and requires further research 2.