Thyroid-stimulating hormone (TSH) is released from the pituitary gland to stimulate the thyroid to secrete hormones (T3, T4). When sufficient thyroid hormone is circulating, negative feedback causes a normally functioning pituitary to slow or stop the release of TSH. In primary hypothyroidism, the thyroid is unable to synthesize enough T3 or T4, slowing the metabolic rate. In response to low circulating thyroid hormones, the pituitary continues to release TSH, resulting in high TSH levels. Levothyroxine (Synthroid), a thyroid hormone replacement drug, is commonly used to treat hypothyroidism. Levothyroxine dosing is adjusted to regulate circulating thyroid hormone levels; this creates a euthyroid (normal) state and TSH levels are decreased (Option 2).
(Options 1 and 3) Decreasing the dose or discontinuing levothyroxine would lead to increased TSH and worsening hypothyroidism as the amount of circulating thyroid hormone. decreases.
(Option 4) Levothyroxine should be taken on a consistent morning schedule, at least 30 minutes before a meal. Foods containing certain ingredients (eg, walnuts, soy products, dietary fiber, calcium) can decrease drug absorption.
Educational objective: In primary hypothyroidism, the thyroid does not produce enough hormones (T3, T4). In response to low circulating thyroid hormones, the pituitary continues to release TSH, resulting in high levels of circulating TSH. Levothyroxine is usually started or increased to lead to a euthyroid (normal) state.
Thyroid-stimulating hormone (TSH) is released from the pituitary gland to stimulate the thyroid to secrete hormones (T3, T4). When sufficient thyroid hormone is circulating, negative feedback causes a normally functioning pituitary to slow or stop the release of TSH. In primary hypothyroidism, the thyroid is unable to synthesize enough T3 or T4, slowing the metabolic rate. In response to low circulating thyroid hormones, the pituitary continues to release TSH, resulting in high TSH levels. Levothyroxine (Synthroid), a thyroid hormone replacement drug, is commonly used to treat hypothyroidism. Levothyroxine dosing is adjusted to regulate circulating thyroid hormone levels; this creates a euthyroid (normal) state and TSH levels are decreased (Option 2).
(Options 1 and 3) Decreasing the dose or discontinuing levothyroxine would lead to increased TSH and worsening hypothyroidism as the amount of circulating thyroid hormone. decreases.
(Option 4) Levothyroxine should be taken on a consistent morning schedule, at least 30 minutes before a meal. Foods containing certain ingredients (eg, walnuts, soy products, dietary fiber, calcium) can decrease drug absorption.
Educational objective: In primary hypothyroidism, the thyroid does not produce enough hormones (T3, T4). In response to low circulating thyroid hormones, the pituitary continues to release TSH, resulting in high levels of circulating TSH. Levothyroxine is usually started or increased to lead to a euthyroid (normal) state.
