Israel Medical Association Journal

Background: Hepatotoxicity due to intravenous amiodarone (HIVAD) is a rare side effect with a distinct pattern of enzyme disturbances compared to liver damage from oral amiodarone. Intravenous amiodarone is administered for acute arrhythmias often causing heart failure. The enzyme abnormalities and clinical setting are very similar to that of ischemic hepatitis, a far more common condition.

Objectives:  To ascertain if acute HIVAD exists as a separate entity or whether reported cases may be explained by ischemic hepatitis.

Methods: In this case-control retrospective study the files of hospitalized patients with markedly elevated aminotransferases were reviewed for the diagnoses of HIVAD or ischemic hepatitis. Medline was searched for published cases of HIVAD. Pooled data of all patients with HIVAD were compared to a control group with ischemic hepatitis.

Results: There were no significant differences in the clinical characteristics, laboratory results or histological findings between HIVAD and ischemic hepatitis patients.

Conclusions: In our opinion, there is currently insufficient data to support the existence of distinct HIVAD, and ischemic hepatitis is a more probable diagnosis in most reported cases. Withdrawing amiodarone because of assumed hepatic damage could deprive patients of a life-saving therapy.
 

Background: Drug-induced thyrotoxicosis is not uncommon. It may worsen life-threatening arrhythmias and may be refractory to medical treatment. Near-total thyroidectomy presents a valid alternative to medical therapy and should be considered early in the management of the disease.

Objectives: To assess whether near-total thyroidectomy was a viable approach for our patients.

Methods: Twelve patients – 7 men and 5 women, aged 63 to 82 years – presented with drug-induced fulminant thyrotoxicosis following 1 to 12 months of amiodarone treatment (11 patients, mean 7 months) and after a 6 months course of interferon-alpha treatment (one patient). Medical therapy included propylthiouracil in doses up to 1200 mg/day in all patients and a beta-receptor antagonist in seven. Five patients had to stop amiodarone treatment and start high doses of steroids. A thyroid scan was performed in all patients using 5 mCi of Tc-99m pertechnetate. The thyroid scan showed absent uptake of the tracer in the thyroid bed in all patients, precluding the use of radioablation.

Results: Four patients (three with AIT[1] and one with interferon therapy) who did not respond to 3 months of medical therapy required surgical thyroidectomy due to severe unremitting thyrotoxicosis. A near-total thyroidectomy resulted in rapid correction of thyrotoxicosis, enabling continuation of the anti-arrhythmic drug. There were no intraoperative or postoperative arrhythmias. Subsequently, all patients recovered rapidly and remained well and euthyroid on thyroxine replacement therapy.

Conclusions: Since surgery results in rapid control of thyrotoxicosis and permits continued therapy with amiodarone, we suggest that near-total thyroidectomy warrants consideration as a definitive treatment for resistant amiodarone or interferon-induced thyrotoxicosis.

Objective: To identify risk factors and associated conditions that may cause TdP[1] in patients on chronic amiodarone treatment.

Methods: We reviewed the data of six consecutive patients on chronic amiodarone treatment who were admitted to the intensive cardiac care unit due to syncope and TdP.

Results: The patients’ median age was 73.5 years, and five were women. Concomitantly, loratadine was given to two patients and trazodone to one patient. Associated and attributing conditions to the development of TdP were hypokalemia in three patients, drug-induced bradycardia in one and reduced left ventricular function in four.

Conclusions: TdP associated with chronic amiodarone treatment may occur when amiodarone is co-administered with drugs that may potentially prolong QT interval. Additional risk factors for amiodarone-associated TdP include female gender, hypokalemia, reduced left ventricular function and bradycardia.

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[1] TdP = torsade de pointes