All of the following are true about amiodarone induced thyroid dysfunction except? (DNB June 2010)
|A||Both hyperthyroidism & Hypothyroidism can occur|
|B||Hypothyroidism is more common in men|
|C||Amiodarone inhibits deiodinase activity|
|D||Amiodarone therapy is associated with initial reduction of serum T4 levels|
Hypothyroidism is more common in men
Drug – induced hypothyroidism
1). Lithium carbonate
a. Due to the high iodine content of the Amiodarone (37.3% by weight), abnormalities in thyroid function are common.
b. Amiodarone is structurally similar to thyroxine , which contributes to the effects of amiodarone on thyroid function.
c. Both under- and overactivity of the thyroid may occur on amiodarone treatment.
d. Hypothyroidism (slowing of the thyroid, due to the Wolff-Chaikoff effect) can also occur.
e. Hyperthyroidism (an overactive thyroid, due to the Jod-Basedow Effect) can also occur.
f. Amiodarone associated hypothyroidism is more common in women and individual with positive TPO antibodies.
g. Mechanism of Action: Amiodarone inhibits deiodinase activity.
h. Amiodarone therapy is associated with initial reduction of serum T4 levels