nexterone

Amiodarone shows considerable interindividual variation in response. Although a starting dose adequate to suppress life-threatening arrhythmias is needed, close monitoring with adjustment of dose is essential. The recommended starting dose of NEXTERONE is about 1000 mg over the first 24 hours of therapy, delivered by the following infusion regimen: After the first 24 hours, continue the maintenance infusion rate of 0.5 mg/min (720 mg per 24 hours) by directly infusing NEXTERONE Premixed Injection (360 mg/200 mL; 1.8 mg/mL) at a rate of 0.278 mL/min. The rate of the maintenance infusion may be increased to achieve effective arrhythmia suppression. In the event of breakthrough episodes of VF or hemodynamically unstable VT, use 150 mg supplemental infusions of NEXTERONE (infused over 10 minutes to minimize the potential for hypotension). The first 24-hour dose may be individualized for each patient; however, in controlled clinical trials, mean daily doses above 2100 mg were associated with an increased risk of hypotension. Do not exceed an initial infusion rate of 30 mg/min. Based on the experience from clinical studies of intravenous amiodarone, a maintenance infusion of up to 0.5 mg/min can be continued for 2 to 3 weeks regardless of the patient's age, renal function, or left ventricular function. There has been limited experience in patients receiving intravenous amiodarone…

The following adverse reactions are described in Warnings and Precautions: hypotension, rhythm disturbances, hepatic injury, pulmonary injury, thyroid injury, hypersensitivity. 6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. In a total of 1836 patients in controlled and uncontrolled clinical trials, 14% of patients received intravenous amiodarone for at least one week, 5% received it for at least 2 weeks, 2% received it for at least 3 weeks, and 1% received it for more than 3 weeks, without an increased incidence of severe adverse reactions. The mean duration of therapy in these studies was 5.6 days; median exposure was 3.7 days. The most important adverse reactions were hypotension, asystole/cardiac arrest/pulseless electrical activity (PEA), cardiogenic shock, congestive heart failure, bradycardia, liver function test abnormalities, VT, and AV block. Overall, treatment was discontinued for about 9% of the patients because of adverse reactions. The most common adverse reactions leading to discontinuation of intravenous amiodarone therapy were hypotension (1.6%), asystole/cardiac arrest/PEA (1.2%), VT (1.1%), and cardiogenic shock…

NEXTERONE is contraindicated in patients with: • Known hypersensitivity to any of the components of NEXTERONE Premixed Injection, including iodine. Hypersensitivity reactions may involve rash, angioedema, cutaneous/mucosal hemorrhage (bleeding), fever, arthralgias (joint pains), eosinophilia (abnormal blood counts), uritcaria (hives), thrombotic thrombocytopenic purpura, or severe periarteritis (inflammation around blood vessels). • Cardiogenic shock. • Marked sinus bradycardia. • Second- or third-degree atrio-ventricular (AV) block unless a functioning pacemaker is available.

There have been cases, some fatal, of amiodarone overdose. Effects of an inadvertent overdose of intravenous amiodarone include hypotension, cardiogenic shock, bradycardia, AV block, and hepatotoxicity. Treat hypotension and cardiogenic shock by slowing the infusion rate or with standard therapy: vasopressor drugs, positive inotropic agents, and volume expansion. Bradycardia and AV block may require temporary pacing. Monitor hepatic enzyme concentrations closely. Neither amiodarone nor DEA is dialyzable.

U.S. Poison Control: call or text 1-800-222-1222 (free, 24/7). In an emergency call 911. From the FDA label; not medical advice.

7.1 Pharmacodynamic Interactions Drugs prolonging the QT interval: Co-administration of drugs prolonging the QT interval (such as class I and III antiarrhythmics, lithium, certain phenothiazines, tricyclic antidepressants, certain fluoroquinolone and macrolide antibiotics, azole antifungals, halogenated inhalation anesthetic agents) increases the risk of Torsade de Pointes. In general, avoid concomitant use of drugs that prolong the QT interval [see Warnings and Precautions ( 5- 5.4)]. Drugs that slow heart rate: Concomitant use of drugs with depressant effects on the sinus and AV node (e.g., digoxin, beta blockers, verapamil, diltiazem, ivabradine, clonidine) can potentiate the electrophysiologic and hemodynamic effects of amiodarone, resulting in bradycardia, sinus arrest, and AV block. Monitor heart rate in patients on amiodarone and concomitant drugs that slow heart rate. 7.2 Pharmacokinetic Interactions Effect of other drugs on amiodarone Amiodarone is metabolized to the active metabolite desethylamiodarone (DEA) by the cytochrome P450 (CYP450) enzyme group, specifically CYP3A and CYP2C8. Amiodarone has the potential for interactions with drugs or substances that may be substrates, inhibitors or inducers of CYP450 enzymes (e.g., inhibitors such as protease inhibitors, grapefruit juice, certain fluoroquinolone and macrolide antibiotics, azole antifungals and inducers such as St. John’s Wort) or P-glycoprotein. In view of the long and variable half-life of amiodarone, potential for drug interactions exists not only with concomitant medication but also with drugs administered after discontinuation of amiodarone [see Clinical Pharmacology ( 12- 12.3)]. Patients should avoid grapefruit juice beverages while taking amiodarone because exposure to amiodarone is significantly increased [see Clinical Pharmacology ( 12- 12.3)]. Effect of amiodarone on other drugs Amiodarone and DEA are inhibitors of P-glycoprotein and certain CYP450 enzymes, including CYP1A2, CYP2C9, CYP2D6 and CYP3A [see Clinical Pharmacology ( 12- 12.3)]. Antiarrhythmics: The metabolism of quinidine, procainamide, flecainide can be inhibited by amiodarone. In general, initiate any added antiarrhythmic drug at a lower than usual dose and monitor the patient carefully. During transfer to oral amiodarone, reduce the dose levels of previously administered agents by 30 to 50% several days after the addition of oral amiodarone. Review the continued need for the other antiarrhythmic agent after the effects of amiodarone have been established, and attempt discontinuation [see Clinical Pharmacology ( 12- 12.3)]. Digoxin: In patients receiving digoxin therapy, administration of oral amiodarone results in an increase in serum digoxin concentration. Reduce dose of digoxin by half or discontinue digoxin. If digitalis treatment is continued, monitor serum levels closely and observe patients for clinical evidence of toxicity [see Clinical Pharmacology ( 12- 12.3)]. HMG-CoA Reductase Inhibitors: Limit the dose of simvastatin in patients on amiodarone to 20 mg daily. Limit the daily dose of lovastatin to 40 mg. Lower starting and maintenance doses of other CYP3A4 substrates (e.g., atorvastatin) may be required as amiodarone may increase the plasma concentration of these drugs. Anticoagulants: Potentiation of warfarin-type (CYP2C9 and CYP3A substrate) anticoagulant response is almost always seen in patients receiving amiodarone and can result in serious or fatal bleeding. Since the concomitant administration of warfarin with amiodarone increases the INR by 100% after 3 to 4 days, reduce the dose of the anticoagulant by one-third to one-half, and monitor INR closely. Cyclosporine (CYP3A substrate) administered in combination with oral amiodarone has been reported to produce persistently elevated plasma concentrations of cyclosporine resulting in elevated creatinine, despite reduction in dose of cyclosporine. Monitor cyclosporine drug levels and renal function in patients taking both drugs. Increased steady-state levels of phenytoin during concomitant therapy with amiodarone have been reported. Monitor phenytoin levels in patients taking both drugs. 7.3 Serious Symptomatic Bradycardia When Co-administered with Ledipasvir/Sofosbuvir or with Sofosbuvir with Simeprevir Postmarketing cases of symptomatic bradycardia, some requiring pacemaker insertion and at least one fatal, have been reported when ledipasvir/sofosbuvir or sofosbuvir with simeprevir were initiated in patients on amiodarone. Bradycardia generally occurred within hours to days, but in some cases up to 2 weeks after initiating antiviral treatment. Bradycardia generally resolved after discontinuation of antiviral treatment. The mechanism for this effect is unknown. Monitor heart rate in patients taking or recently discontinuing amiodarone when starting antiviral treatment.