Moderate
Probable
Description
Sertraline can increase levothyroxine clearance, particularly in patients with pre-existing hypothyroidism, potentially necessitating levothyroxine dose increases.
Mechanism
Sertraline may induce hepatic CYP enzymes involved in levothyroxine metabolism and increase biliary excretion of thyroid hormone; it may also alter transport proteins that regulate T4 bioavailability.
Clinical Significance
Case series and retrospective reports describe increased levothyroxine dose requirements after initiation of sertraline, with TSH rising despite stable prior replacement therapy.
Management
Recheck TSH 6–8 weeks after starting sertraline in levothyroxine-treated patients; adjust levothyroxine dose as needed; conversely, monitor for signs of hyperthyroidism if sertraline is discontinued.