Amiodarone adverse effects

Ventricular Rate Control is achieved by inhibiting the proportion of electrical impulses conducted from the atria to the ventricles through the AV node. Therefore, drugs that are effective for ventricular rate control are those that inhibit AV nodal impulse conduction P-blockers, diltiazem, verapamil, and digoxin (Tables 6-5 and 6-6). Amiodarone also inhibits AV nodal conduction, but is not a preferred drug for ventricular rate control in AF due to its unfavorable adverse-effect profile (Table 6-6). 

Administration with amiodarone When flecainide is given in the presence of amiodarone, reduce the usual flecainide dose by 50% and monitor the patient closely for adverse effects. Plasma level monitoring is strongly recommended to guide dosage with such combination therapy. 

Hypotension - Hypotension is the most common adverse effect seen with amiodarone IV. Clinically significant hypotension during infusions was seen most often in the first several hours of treatment and appeared to be related to the rate of infusion. Hypotension necessitating alterations in therapy was reported in 3% of patients, with permanent discontinuation required in less than 2% of patients. Treat hypotension initially by slowing the infusion additional standard therapy may be needed. 

Nelfinavir (Viracept) is probably the most commonly used protease inhibitor because of its low incidence of serious adverse effects. Its most common side effects are diarrhea and flatulence these may resolve with continued use. In addition to the drugs contraindicated for use with all protease inhibitors, amiodarone, rifampin, and quinidine are contraindicated in patients taking nelfinavir. 

In the USA, amiodarone is approved for oral and intravenous use to treat serious ventricular arrhythmias. However, the drug is also highly effective for the treatment of supraventricular arrhythmias such as atrial fibrillation. As a result of its broad spectrum of antiarrhythmic action, it is very extensively used for a wide variety of arrhythmias. Amiodarone has unusual pharmacokinetics and important extracardiac adverse effects. Dronedarone, an analog that lacks iodine atoms, is under investigation. 

T effects OF amiodarone, astemizole, atorvastadn, barbiturates, bepridil, bupropion, cerivastatin, cisapride, clorazepate, clozapine, clarithromycin, desipramine, diazepam, encainide, ergot alkaloids, estazolam, flecainide, flurazepam, indinavir, ketoconazole, lovastatin, meperidine, midazolam, nelfinavir, phenytoin, pimozide, piroxicam, propafenone, propoxyphene, quinidine, rifabutin, saquinavir, sildenafil, simvastatin, SSRIs, TCAs, terfenadine, triazolam, troleandomycin, zolpidem X effects W/ barbiturates, carbamazepine, phenytoin, rifabutin, rifampin, St. John s wort, tobacco X effects OF didanosine, hypnotics, methadone, OCPs, sedatives, theophylline, warfarin EMS T Effects of amiodarone, diazepam, midazolam and BBs, may need X- doses concurrent use of Viagra-type drugs can lead to hypotension X- effects of warfarin concurrent EtOH use can T adverse effects T glucose ODs May cause an extension of adverse SEs symptomatic and supportive Rivasrigmine (Exelon) [Cholinesterase Inhibitor/Anri ... 

Amiodarone-induced hyponatremia, due to the syndrome of inappropriate secretion of antidiuretic hormone, is rare (SEDA-21, 199 25). The mechanism is unknown. Unlike other adverse effects of amiodarone, it seems to occur rapidly and to resolve rapidly after withdrawal. 

It has been suggested that potassium perchlorate should be used in the treatment of type 1 hyperthyroidism and glucocorticoids in the treatment of type 2 (SEDA-21, 199). Since hypothyroidism due to amiodarone tends to occur in areas in which there is sufficient iodine in the diet, it has been hypothesized that an iodinated organic inhibitor of hormone synthesis is formed and that the formation of this inhibitor is inhibited by perchlorate to a greater extent than thyroid hormone iodination is inhibited, since the iodinated lipids that are thought to be inhibitors require about 10 times more iodide than the hormone. However, there is a high risk of recurrence after treatment with potassium perchlorate, and it can cause serious adverse effects (SED-13,1281). 

Amiodarone has a higher incidence of side effects than sotalol. Seventy-five percent of patients report side effects over 5 years with 15-35 percent requiring discontinuance of the drug. Severe adverse effects, including pulmonary fibrosis, can occur with usual doses of amiodarone and may be lethal or irreversible or persist for months after treatment is stopped. 

Adverse effects Amiodarone shows a variety of toxic effects. After long-term use, more than one half of the patients receiving the drug show side effects sufficiently severe to prompt its discontinuation. Some of the more common effects include interstitial pulmonary fibrosis, gastrointestinal tract intolerance, tremor, ataxia, dizziness, hyper- or hypothyroidism, liver toxicity, photosensitivity, neuropathy, muscle weakness, and blue skin discoloration caused by iodine accumulation in the skin. As noted earlier (see p. 166) recent clinical trials have shown that amiodarone did not reduce incidence of sudden death or prolong survival in patient with congestive heart failure (CHF). 

CIMETIDINE, RANITIDINE ANTIARRHYTHMICS-AMIODARONE, FLECAINIDE, MEXILETINE, PROCAINAMIDE, PROPAFENONE Likely t plasma concentrations of these antiarrhythmics and risk of adverse effects Cimetidine inhibits CYP2D6-mediated metabolism of flecainide, mexiletine, procainamide and propafenone. Ranitidine is a much weaker CYP2D6 inhibitor. Cimetidine is a potent inhibitor of organic cation transport in the kidney, and the elimination of procainamide is impaired Monitor PR and BP at least weekly until stable. Warn patients to report symptoms of hypotension (lightheadedness, dizziness on standing, etc.). Consider alternative acid suppression therapy... 

Adenosine is the treatment of choice for diagnosis and reversal of supraventricular arrhythmias. Verapamil is an alternative for the management of narrow complex tachycardias. Amiodarone is the most effective drug at reversing atrial fibrillation, and in prevention of ventricular arrhythmias, but has several adverse effects. 

Amiodarone is highly effective in treating both ventricular and supraventricular dysrhythmias (1). Its pharmacology, therapeutic uses, and adverse effects and interactions have been extensively reviewed (2-14). 

Amiodarone and carvedilol have been used in combination in 109 patients with severe heart failure and left ventricular ejection fractions of 0.25 (16). They were given amiodarone 1000 mg/week plus carvedilol titrated to a target dose of 50 mg/day. A dual-chamber pacemaker was inserted and programmed in back-up mode at a basal rate of 40. Significantly more patients were in sinus rhythm after 1 year, and in 47 patients who were studied for at least 1 year the resting heart rate fell from 90 to 59. Ventricular extra beats were suppressed from 1 to 0.1/day and the number of bouts of tachycardia over 167 per minute was reduced from 1.2 to 0.3 episodes per patient per 3 months. The left ventricular ejection fraction increased from 0.26 to 0.39 and New York Heart Association Classification improved from 3.2 to 1.8. The probability of sudden death was significantly reduced by amiodarone plus carvedilol compared with 154 patients treated with amiodarone alone and even more so compared with 283 patients who received no treatment at all. However, the study was not randomized, and this vitiates the results. The main adverse effect was s)mptomatic bradycardia, which occurred in seven patients two of those developed atrioventricular block and four had sinoatrial block and/or sinus bradycardia one patient developed slow atrial fibrillation. 

In 186 patients randomized equally to amiodarone 200 mg/day, sotalol 160-480 mg/day, or placebo, the incidence of atrial fibrillation after 6 months was higher in those taking placebo compared with amiodarone and sotalol and higher in those taking sotalol compared with amiodarone (19). Of the 65 patients who took amiodarone, 15 had significant adverse effects after an average of... 

In a meta-analysis of five randomized, placebo-controlled trials of intravenous amiodarone about 500-2200 mg over 24 hours in the treatment of recent-onset atrial fibrillation in 410 patients, the incidence of adverse events was 27% with amiodarone and 11% with placebo (28). Intravenous amiodarone was significantly more effective than placebo in producing cardioversion. The most common adverse effects of intravenous amiodarone were phlebitis, bradycardia, and hypotension most of these effects were not considered to be dose-limiting. 

Of 85 patients with persistent atrial fibrillation after balloon mitral valvotomy given amiodarone (600 mg/day for 2 weeks and 200 mg/day thereafter), 33 converted to sinus rhythm (29). Of the other 52 patients, who underwent DC cardioversion at 6 weeks, 41 converted to sinus rhythm. Six patients had adverse effects attributable to amiodarone. Five had mild gastrointestinal symptoms, such as abdominal discomfort and nausea. One developed hypothyroidism after 3 months, which resolved when the dosage of amiodarone was reduced to 100 mg/day. 

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