Very early onset of acute amiodarone pulmonary toxicity presenting with hemoptysis

Amiodarone-induced diffuse alveolar haemorrhage: a rare but potentially life-threatening complication of a commonly prescribed medication

Amiodarone is an antiarrhythmic agent that is used commonly in clinical practice. It is associated with many side effects, the most common being pulmonary manifestations. Interstitial pneumonitis is one of the most common complications, however rarely amiodarone can cause diffuse alveolar haemorrhage (DAH) too. We describe the case of a 73-year-old woman who presented with shortness of breath and haemoptysis 4 days after starting amiodarone. She was diagnosed with amiodarone-induced DAH based on imaging and bronchoalveolar lavage. She was treated with intravenous and then oral steroids, and amiodarone was discontinued. The patient made a significant clinical and radiological recovery. She was discharged 10 days after her presentation. This case highlights a rare but potentially life-threatening complication of a commonly used medication.

Rapid onset of amiodarone induced pulmonary toxicity after lung lobe resection - A case report and review of recent literature

Amiodarone-induced pulmonary toxicity (APT) is a severe side effect that can lead to lung fibrosis or fatal respiratory failure. Usually APT occurs during long term therapy after administration of prolonged loading doses or high cumulative doses. We present the case of a 58 year old woman who underwent thoracic surgery with lobe resection. She developed atrial fibrillation with hemodynamic-instability on the first post-operative day. We initiated amiodarone therapy and four days later she developed respiratory failure. The pulmonary function further deteriorated showing signs of an acute respiratory distress syndrome (ARDS). We therefore started mechanical ventilation, but still the gas exchange did not improve. A computer tomography-(CT)-scan presented bilateral interstitial and alveolar infiltrations. The patient also presented with leukocytosis, elevated C-reactive protein (CRP) levels however without elevated procalcitonin (PCT) concentrations. In the tracheal secretion we only harvested foam cells, but got no evidence for pathogens causing pneumonia. We immediately started glucocorticoid therapy with prednisolone 50 mg/d for five days. Almost instantaneously the gas exchange ameliorated. We were able to wean the patient from the respirator within five days. Pulmonary infiltrations were nearly vanished in a CT-scan few days later and completely disappeared in follow up examinations. This case demonstrates a per-acute onset of APT caused by a low loading dose in association with thoracic surgery. The initiation of glucocorticoid therapy in parallel to amiodarone withdrawal led to full recovery of the patient. One should consider APT when signs of pulmonary failure occur during brief periods of amiodarone therapy especially after thoracic surgery.

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Amiodarone-induced pulmonary toxicity (APT) can develop after low dose and short term amiodarone therapy.

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The early generation of APT is supported by thoracic surgery.

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APT can cause severe adult respiratory distress syndrome, leading to respiratory failure.

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Glucocorticoid therapy ameliorates APT symptoms and can restore respiratory failure in early state.

Amiodarone-induced alveolar haemorrhage: a rare complication of a common medication

Amiodarone pulmonary toxicity (APT) is a common and distinctive form of drug-induced lung injury. Several patterns have been described and the most common pattern of APT is interstitial pneumonitis. However, amiodarone-induced diffused alveolar haemorrhage is rarely reported. We describe a case of early onset of APT manifested by respiratory distress, haemoptysis, severe hypoxia and bilateral pulmonary infiltrates that was finally diagnosed with amiodarone-induced diffuse alveolar haemorrhage. High suspicion of APT in patients with these non-specific clinical symptoms is needed. Early recognition and treatment are imperative.

Vanoxerine: cellular mechanism of a new antiarrhythmic

INTRODUCTION

There remains an unmet need for safe and effective antiarrhythmic drugs, especially for the treatment of atrial fibrillation. Vanoxerine is a drug that is free of adverse cardiac events in normal volunteers, yet is a potent blocker of the hERG (hK(v)11.1) cardiac potassium channel. Consequently,we hypothesized that vanoxerine might also be a potent blocker of cardiac calcium (Ca) and sodium (Na) currents, and would not affect transmural dispersion of repolarization.

METHODS

The whole cell patch clamp technique was used to measure currents from cloned ion channels overexpressed in stable cell lines and single ventricular myocytes. We measured intracellular action potentials from canine ventricular wedges and Purkinje fibers using sharp microelectrode technique.

RESULTS

We found that vanoxerine was a potent hK(v)11.1 blocker, and at submicromolar concentrations, it blocked Ca and Na currents in a strongly frequency-dependent manner. In the canine ventricular wedge preparation vanoxerine did not significantly affect transmural action potential waveforms, QT interval or transmural dispersion of repolarization.

CONCLUSIONS

Vanoxerine (1) is a potent blocker of cardiac hERG, Na and Ca channels; (2) block is strongly frequency-dependent especially for Na and Ca channels; and (3) transmural dispersion of ventricular repolarization is unaffected. The multichannel block and repolarization uniformity resemble the effects of amiodarone, the exemplar atrial fibrillation drug. Vanoxerine is a completely different chemical and has none of amiodarone's toxic effects. Vanoxerine has characteristics of a potentially effective and safe antiarrhythmic.

Amiodarone-induced pulmonary toxicity

AIMS

A number of factors have been hypothesized to increase the risk of amiodarone-induced pulmonary toxicity (AIPT). This study aimed to confirm these risk factors and determine whether a cohort of tertiary hospital patients diagnosed with AIPT demonstrated comparable characteristics.

METHODS

Phase I of this study involved compilation of a database of adverse reactions to amiodarone reported to the Australian and US drug agencies, and identification of risk factors for AIPT using logistic regression analysis. In Phase II, AIPT cases were identified via a retrospective review of medical records of patients discharged from Fremantle Hospital and Health Service, Western Australia (FHHS) between 2000 and 2005 with diagnosed interstitial lung disease. Data were collected regarding these patients' risk factors for AIPT and compared with those previously identified in Phase I.

RESULTS

A total of 237 cases of AIPT were identified from agency data. Patients aged > 60 years and those on amiodarone for 6-12 months (odds ratio 18.28, 95% confidence interval 6.42, 52.04) were determined to be at the highest risk of AIPT. Australian data also suggested increased risk in patients who had received cumulative doses of 101-150 g. The seven AIPT cases identified among the FHHS patients were all at high risk of AIPT based on their age and duration of amiodarone therapy.

CONCLUSION

Contrary to previous findings, only patient age and the duration of amiodarone therapy were confirmed as significant risk factors for AIPT. Targeted monitoring of these patients may facilitate early identification and management of AIPT.

Tc-99m HMPAO Scintigraphy in Amiodarone-Induced Acute Lung Toxicity

PURPOSE

This case demonstrates the use of Tc-99m HMPAO scintigraphy in amiodarone (AD)-induced lung toxicity. The aim of this presentation is also to discuss different scintigraphic modalities in the diagnosis and follow up in AD-induced lung toxicity.

MATERIALS AND METHODS

A 77-year-old man, with a suspicious AD-induced acute lung toxicity, underwent Tc-99m DTPA aerosol inhalation scintigraphy and Tc-99m HMPAO scintigraphy.

RESULTS

Rapid alveolar clearance of Tc-99m DTPA was found during AD therapy and increased lung uptake of Tc-99m HMPAO was also demonstrated. These findings supported the diagnosis AD lung toxicity. After cessation of therapy, Tc-99m DTPA alveolar clearance was decreased. Although there was some decrease in L/H and L/B ratios of Tc-99m HMPAO after 3 weeks of stopping therapy, Tc-99m HMPAO uptake in the lungs was still continued. This finding may be the result of ongoing pulmonary inflammation as a result of the long half-life of AD.

CONCLUSION

Compared with Tc-99m DTPA aerosol inhalation scintigraphy, Tc-99m HMPAO scintigraphy may have a role in the diagnosis of AD lung toxicity. Nevertheless, there is a need for longitudinal studies investigating patients under AD therapy using follow-up Tc-9m HMPAO scintigraphy.

Amiodarone-induced Alveolar Hemorrhage

Amiodarone is increasingly prescribed for patients with ventricular and supraventricular tachyarrhythmias. Many adverse effects have been reported due to this drug and include injury to the liver, thyroid, cornea, skin, and neuromuscular system. Pulmonary toxicity is one of the more serious side effects of this anti-arrhythmic drug and is potentially fatal. Since the first case of amiodarone-induced pneumonitis was described in the early 1980s, amiodarone pneumonitis has been recognized as a distinctive and not uncommon form of drug-induced lung injury. On the other hand, amiodarone-induced pulmonary toxicity resulting in alveolar hemorrhage is rare. The authors report a patient with amiodarone-induced alveolar hemorrhage and review the literature.

A review of class III antiarrhythmic agents for atrial fibrillation: maintenance of normal sinus rhythm

A noteworthy shift from class I to class III antiarrhythmic agents for suppression of atrial fibrillation has occurred. Sotalol, amiodarone, and dofetilide have been evaluated for their ability to maintain sinus rhythm in patients with chronic atrial fibrillation. All of these agents are moderately effective; however, amiodarone appears to be most efficacious. Aside from their common class III actions, these agents have profoundly different pharmacologic, pharmacokinetic, safety, and drug interaction profiles that help guide drug selection. Amiodarone and dofetilide are safe in patients who have had a myocardial infarction and those with heart failure. The safety of commercially available d,l-sotalol in these patients is poorly understood. Torsades de pointes is the most serious adverse effect of sotalol and dofetilide, and risk increases with renal dysfunction. Amiodarone has minimal proarrhythmic risk but has numerous noncardiac toxicities that require frequent monitoring. Overall, an ideal antiarrhythmic agent does not exist, and drug selection should be highly individualized.