What role does CYP2C19 play in fatigue?

CYP2C19 is a liver enzyme involved in metabolizing many drugs, including certain antidepressants (e.g., escitalopram, amitriptyline) and proton pump inhibitors (e.g., omeprazole). Genetic variants (*2, *3, *17) can classify individuals as poor, intermediate, normal, or ultrarapid metabolizers. In poor metabolizers, standard doses of some drugs may accumulate, potentially causing side effects such as sedation, dizziness, or fatigue. However, there is no established direct link between CYP2C19 genotype and fatigue independent of medication. The provided context does not contain any studies or statements addressing CYP2C19 and fatigue specifically. Therefore, the evidence is considered mechanistic/indirect. Consumer DNA tests may report CYP2C19 variants, but clinical utility for fatigue is limited. Always interpret such results with a healthcare professional.