tokens: The most common symptomatic adverse reactions were tremor or ataxia ( 35 %), nausea and anorexia ( 8 %), visual halos or blurring ( 6 %), thyroid function abnormalities ( 6 %) and pulmonary interstitial infiltrates ( 5 %). Although large - dose amiodarone is highly effective in the long - term treatment of VT or VF refractory to conventional antiarrhythmic drugs , it causes significant toxicity in approximately 50 % of patients .