A 35-year-old woman on levothyroxine 75 mcg daily for hypothyroidism reports persistent fatigue and myalgias despite a normal TSH of 2.1 mIU/L 6 weeks ago. She takes her medication with breakfast and her calcium supplement. Recent labs show TSH 6.8 mIU/L and free T4 0.9 ng/dL. Which of the following is the most likely cause of her worsening symptoms?
- A)Malabsorption of levothyroxine due to calcium supplement interferenceGABARITO
- B)Development of secondary hypothyroidism from pituitary insufficiency
- C)Noncompliance with levothyroxine therapy
- D)Thyroid hormone resistance syndrome
- E)Graves' disease superimposed on treated hypothyroidism
Explicação
Calcium supplements significantly impair levothyroxine absorption when taken concurrently, reducing bioavailability. The patient should take levothyroxine on an empty stomach, at least 30-60 minutes before food or supplements. Taking levothyroxine with breakfa... Ver explicação completa e trilha adaptativa →