Amiodarone: a candidate for the title ‘riskiest drug’
Hugh Mcgavock in Pitfalls in Prescribing and How to Avoid Them, 2017
Amiodarone is a remarkably useful drug for treating cardiac arrhythmias. Its indications include atrial fibrillation and flutter, paroxysmal ventricular tachycardia, nodal and ventricular tachycardia, ventricular fibrillation and tachyarrhythmia. It is part of the management of many patients, greatly improving their quality of life and life expectancy. The BNF states that amiodarone ‘should be initiated only under hospital or specialist supervision’, and with very good reason. This is because amiodarone presents the prescriber with two complex problems: 1 an unenviable list of adverse drug reactions (ADRs) due to amiodarone itself 2 an extensive and complex set of interactions with many other commonly used drugs – adverse drug interactions (ADIs). Let us examine these problems separately.
Thyroid function
Martin Andrew Crook in Clinical Biochemistry & Metabolic Medicine, 2013
Amiodarone is sometimes used to treat certain cardiac arrhythmias. This drug can evoke hypothyroidism, partly because it interrupts the conversion of T to T. However, it contains iodine and can also evoke thyrotoxicosis by the Jod–Basedow or type 1 phenomenon. Conversely, it may elicit disruptive thyroiditis and thyrotoxicosis with raised interleukin-6 concentration (type 2 phenomenon). The drug has a long half-life (40–100 days) and thus takes a long time to clear from the body (see Chapter 25).
Heart failure
Clive Handler, Gerry Coghlan, Nick Brown in Management of Cardiac Problems in Primary Care, 2018
Myocardial ischaemia, fibrosis and atrial dilatation may result in atrial fibrillation, which can precipitate heart failure and stroke. It is important to diagnose this promptly and treat patients with warfarin to reduce the risk of stroke. Amiodarone is useful for treating supraventricular and ventricular tachycardias and it may, if the arrhythmia has occurred recently and the heart is not dilated, restore sinus rhythm. It is also used to improve the chances of successful electrical cardioversion in patients with atrial fibrillation. It does not improve survival in chronic heart failure, and is not indicated for primary prevention of arrhythmias. Side-effects include nausea and vomiting, taste disturbance, bradycardia, hyper- and hypothyroidism, corneal deposits, photosensitivity, hepatitis, pulmonary fibrosis, and peripheral neuropathy and myopathy. Low doses reduce the risk of side effects
Reduced intravenous toxicity of amiodarone nanosuspension in mice and rats
Published in Drug and Chemical Toxicology, 2013
Ester Lovšin Barle, Manica Černe, Luka Peternel, Miha Homar
The toxicity of amiodarone Lek formulation (test formulation) was investigated after a single intravenous (i.v.) administration to mice and rats. When compared to the reference item, Cordarone (Cordarone®; Wyeth Pharmaceuticals Inc., Collegeville, Pennsylvania, USA), median lethal dose (LD50) after i.v. administration in female mice was 294.0 mg/kg body weight (b.w.) for the test formulation and 227.5 mg/kg b.w. for Cordarone. In female rats after i.v. administration, the LD50 value was 269.9 mg/kg b.w. for the test formulation and 192.4 mg/kg b.w. for Cordarone. By altering the particle size of amiodarone in the Lek formulation, we were able to improve the solubility of amiodarone, thereby decreasing the number and quantity of excipients needed for preparation of the i.v. formulation and, consequently, reduced the acute toxic effects observed in the present study.
Dronedarone or amiodarone for rhythm control for atrial fibrillation: implications from the DIONYSOS study
Published in Expert Opinion on Pharmacotherapy, 2010
Management of persistent AF involves rhythm or rate control strategies and thromboprophylaxis for cardioembolic events. Although amiodarone appears to be more effective than other current antiarrhythmics for a rhythm control approach in AF patients, many side effects limit its long-term use. Dronedarone is a new antiarrhythmic drug that may offer advantages for rhythm control, given its relative safety (although not in patients with decompensated heart failure), efficacy and tolerability. With regard to the latter, dronedarone has fewer adverse effects and is better tolerated than amiodarone. Nonetheless, in one head-to-head comparison of dronedarone and amiodarone, the latter drug was superior to dronedarone for maintenance of sinus rhythm post cardioversion, but dronedarone was safer and better tolerated, with useful benefit to decrease hospitalizations and thus healthcare costs. This provides clinicians (and patients) with a new option when choosing antiarrhythmic therapy.
Syndrome of Inappropriate Antidiuretic Hormone in Association with Amiodarone Therapy: A Case Report and Review of Literature
Published in Renal Failure, 2011
Farsad Afshinnia, Neil Sheth, Rachel Perlman
Background: Amiodarone is a class III antiarrhythmic agent that is widely used in the treatment of a variety of arrhythmias. Several different systemic side effects are reported after use of this medication. In this article, we report a case that had developed syndrome of inappropriate antidiuretic hormone (SIADH) after starting treatment with this agent. Case report: The patient is a 66-year-old male with past medical history of hypertension, hyperlipidemia, coronary artery disease, and class III New York Heart Association congestive heart failure who presented with monomorphic nonsustained ventricular tachycardia. A loading dose of amiodarone followed by maintenance dose was started. Baseline serum sodium of 138 mmol/L on admission decreased to 119 mmol/L by day 7, and a diagnosis of SIADH was made. The patient was not taking any other medication known to cause SIADH, nor had any such comorbidity to explain it. Serum sodium increased to 133 and 138 mmol/L, respectively, after 16 and 33 days from discontinuation of amiodarone. Conclusion: SIADH is a rare but serious side effect of amiodarone and practicing physicians should be aware of this complication, particularly after loading dose of the medication.
Related Knowledge Centers
- Arrhythmia
- Benzene
- Potassium Channels
- III
- Gated Sodium Channels
- Benzofurans
- Voltage