Pharmacogenetic Testing: Does It Improve Therapy in Patients With MDD?

• Published in: The clinical advisor 2020-10, Vol.23 (8), p.12-16
• Main Authors: Nolan, Lauren, Solh, Tia M
• Format: Magazinearticle
• Language: English
• Subjects: Antidepressants; Comorbidity; Drug dosages; Enzymes; Laboratories; Mental depression; Metabolism; Metabolites; Patients; Pharmaceutical industry; Self destructive behavior
• ISSN: 1524-7317

Efficacy and tolerability of antidepressants vary among patients, which can make it challenging to relieve patients' symptoms.2 Although no genes have been associated with depression,3 several genetic variants may help clinicians predict how patients with MDD will metabolize antidepressants.4 Performing genetic testing of patients with MDD and matching patients with an antidepressant class based on identification of genetic variants that convey sensitivity to particular antidepressants could improve response to drug therapy in patients with MDD.5 Current Antidepressant Management The process of selecting an antidepressant should take into account cost, tolerability, adverse effect profiles, and patient preferences.2 When evaluating treatment options for patients with MDD, the current standard of care is to initiate an antidepressant at a starting dose and reassess effectiveness within 2 to 4 weeks, with adjustments to monitoring frequency dependent on the patients suicide and self-harm risk, comorbid conditions, age, and concomitant medication use.2 Several metrics are used to determine whether a selected antidepressant is working: * Does the patient feel better? * If not, the clinician should increase dosage to see if the desired effect can be produced. * If dose titration does not reduce symptoms, the clinician should select another antidepressant. * If the patient does feel better, is he or she experiencing adverse effects; if so, how tolerable are they? With ultrarapid drug metabolism, patients may never experience a clinical response to medication. [...]these patients may require higher doses to achieve the same therapeutic effect as patients who metabolize the medication as predicted. * Extensive metabolizers process the medication as predicted. Laboratories often advise clinicians to proceed with caution when prescribing an antidepressant in a patient who is known to be an intermediate metabolizer. * Poor metabolizers process medications significantly more slowly, leaving the patient with higher plasma drug levels than patients who metabolize the medication as predicted. [...]patients who are poor metabolizers are more susceptible to adverse effects or potential toxicity. [...]patients are also at greater risk for adverse effects if practitioners increase dosages of a drug. [...]greater caution should be used during dosage changes in these patients, and closer followup should be considered.