When Fire Meets Ice: a Case of Silent Clinical Course after Massive Levothyroxine and Sedative Co-Ingestion

Levothyroxine overdose is uncommon in adults and often presents with variable clinical severity, ranging from overt thyrotoxicosis to an entirely asymptomatic course.We report the case of a 47-year-old woman with a history of total thyroidectomy who intentionally ingested 10 mg of levothyroxine along with supratherapeutic doses of zolpidem and clonazepam at once in a suicide attempt.She presented three days later without adrenergic or gastrointestinal symptoms.Laboratory tests revealed markedly elevated free thyroxine and total triiodothyronine with suppressed thyroid stimulating hormone.She was treated with propranolol for heart rate control and empirical hydrocortisone in case of adrenal insufficiency.She remained asymptomatic with gradual biochemical improvement and normalization of thyroid function on follow-up.The protective effect of co-ingested supratherapeutic doses of gamma-aminobutyric acid (GABA)-ergic agents suggests a potential role for anti-anxiety medications in mitigating severe adrenergic symptoms in endogenous thyrotoxicosis, such as Graves' disease.