70 下列何種副作用與長期使用抗心律不整藥物amiodarone最無關？

Hyperthyroidism Pulmonary fibrosis Depression Photosensitivity

ans depression

Amiodarone is categorized as a class III antiarrhythmic agent, and prolongs phase 3 of the cardiac action potential. It has numerous other effects however, including actions that are similar to those of antiarrhythmic classes Ia, II, and IV.

Amiodarone shows beta blocker-like and potassium channel blocker-like actions on the SA and AV nodes, increases the refractory period via sodium- and potassium-channel effects, and slows intra-cardiac conduction of the cardiac action potential, via sodium-channel effects.

Amiodarone resembles thyroid hormone, and its binding to the nuclear thyroid receptor might contribute to some of its pharmacologic and toxic actions

Gastrointestinal system and liver

Abnormal liver enzyme results are common in patients on amiodarone. Much rarer are jaundice, hepatomegaly (liver enlargement), and hepatitis (inflammation of the liver).^[14]

Low-dose amiodarone has been reported to cause pseudo-alcoholic cirrhosis.^[15][16]

[edit]Skin

Long-term administration of amiodarone is associated with a blue-grey discoloration of the skin. This is more commonly seen in individuals with lighter skin tones. The discoloration may revert upon cessation of the drug. However, the skin color may not return completely to normal.

Individuals taking amiodarone may become more sensitive to the harmful effects of UV-A light. Using sunblock that also blocks UV-A rays appears to prevent this side effect.

The most serious reaction that is due to amiodarone is interstitial lung disease. Risk factors include high cumulative dose, more than 400 milligrams per day, duration over two months, increased age, and preexisting pulmonary disease. Some individuals were noted to develop pulmonary fibrosis after a week of treatment, while others did not develop it after years of continuous use. Common practice is to avoid the agent if possible in individuals with decreased lung function.

The most specific test of pulmonary toxicity due to amiodarone is a dramatically decreased DL_CO noted onpulmonary function testing.