Flecainide drug interactions

Drug Interactions Other antihypertensive agents Carbamazepine (vasodilators, ACE inhibitors, Rifampin diuretics, and beta-blockers) Phenobarbital Digoxin Cyclosporine Disopyramide Theophylline Flecainide Inhalation anesthetics Quinidine Neuromuscular blocking agents Cimetidine Lithium ... 

The calcium channel blocker mibefradil (Posicor ) was removed from the market in 1998. The headline for the Pink Sheets article describing this action was "Posicor Withdrawal Reflects Complexity of Interaction Profile" (59). Products identified as potentially dangerous in combination with mibefradil included cardiac drugs, such as amiodarone, flecainide, and propafenone oncologic products, such as tamoxifen, cyclophosphamide, etoposide, ifosfamide, and vinblastine and the immunosuppressant medications cyclosporine and tacrolimus. The sponsor s decision to withdraw mibefradil was based on the complexity of the drug interaction information that would have to be communicated to ensure safe usage. 

Drug-Drug and Drug-Food Interactions. Since cinacalcet is metabolized by multiple hepatic enzymes there is potential for drug interactions. Cinacalcet is also a potent inhibitor of the enzyme CYP2D6. As a result, dose adjustments of concomitant medications that are predominantly metabolized by this enzyme and have a narrow therapeutic index such as flecainide, thioridazine, vinblastine, and most tricyclic antidepressants (i.e., amitriptyline) may be required. ... 

Other authors have reported this interaction, and suggest reducing the flecainide dosage by between one-third to one-half when amiodarone is added. " Another study found that amiodarone raised steady-state flecainide plasma levels by 37% in extensive metabolisers, and 55% in poor me-tabolisers of dextromethorphan (a probe drug for CYP2D6 activity). In a later report of this study the authors concluded that these differences were nof clinically imporfanf, and that CYP2D6 phenotype does not affect the extent of the flecainide-amiodarone interaction. An isolated report describes torsade de pointes in a patient on amiodarone when given flecainide. ... 

Tsao YY, Gugger JJ. Delirium in a patient with toxic flecainide plasma concentrations the role of a pharmacokinetic drug interaction with paroxetine. Ann Pharmacother 2009 43(7) 1366-9. 

Drug-drug interactions Flecainide Fleca-inide, a class 1C antidysrhythmic agent, is metabolized by CYP2D6. In a study of the interaction of the CYP2D6 10 allele and paroxetine in an open crossover study in healthy Korean subjects, paroxetine significantly increased the AUC of flecainide and... 

Drug-drug interaction The possible drug interaction between lidocaine and flecainide, both of which are anti-arrhythmics (lidocaine type IB and flecainide type 1C) could be contributing to CNS toxicity after a normal lidocaine dose [40 ]. 

Drugs that may interact include chlorpropamide, lithium, methotrexate, salicylates, tetracyclines, anorexiants, flecainide, mecamylamide, quinidine, and sympathomimetics. 

Drugs that may affect amiodarone include hydantoins, cholestyramine, fluoroquinolones, rifamycins, ritonavir, and cimetidine. Drugs that may be affected by amiodarone include anticoagulants, beta-blockers, calcium channel blockers, cyclosporine, dextromethorphan, digoxin, disopyramide, fentanyl, flecainide, hydantoins, lidocaine, methotrexate, procainamide, quinidine, and theophylline. Drug/Lab test interactions Amiodarone alters the results of thyroid function tests, causing an increase in serum T4 and serum reverse T3 levels and a decline in... 

Secondary> hyperparathyroidism 30 mg PO daily Parathyroid carcinoma 30 mg PO bid titrate q2—4wk based on Ca PTH levels swallow whole take w/ food Caution [C, /—] w/ Szs Disp Tabs SE N/V/D, myalgia, dizziness, 4- Ca2+ Interactions T Effects W/ CYP3A4 inhibitors such as ketoconazole, itraconazole, erythromycin T effects OF drugs metabolized at CYP2D6 such as TCA, thioridazine, flecainide, vinblastine EMS Monitor ECG for signs of hypocalcemia (T QT interval) OD May cause severe hypocalcemia calcium salts can be given... 

Lopinavir/Ritonavir (Kaletra) [Anrirelroviral/Protease Inhibitor] Uses HIV Infxn Action Protease inhibitor Dose Adults. Tx naive 2 tab PO daily or 1 tab PO bid Tx experiencedpt 1 tab PO bid (T dose if w/ amprenavir, efavirenz, fosamprenavir, nelfinavir, nevirapine) Peds. 7-15 kg 12/3 mg/kg PO bid 15-40 kg 10/2.5 mg/kg PO bid >40 kg Adult dose w/ food Caution [C, /-] Numerous interactions Contra w/drugs dependent on CYP3A/CYP2D6 (Table VI-8) Disp Tab, soln SE Avoid disulfiram (soln has EtOH), metronidazole GI upset, asthenia, T cholesterol/triglycerides, pancreatitis protease metabolic synd Interactions T Effects Wl clarithromycin, erythromycin T effects OF amiodarone, amprenavir, azole andfungals, bepridil, cisapride, cyclosporine, CCBs, ergot alkaloids, flecainide, flurazepam, HMG-CoA reductase inhibitors, indinavir, lidocaine, meperidine, midazolam, pimozide, propafenone, propoxyphene, quinidine, rifabutin, saquinavir, sildenafil, tacrolimus, terfenadine, triazolam, zolpidem 1 effects Wl barbiturates, carbamazepine, dexamethasone, didanosine, efavirenz, nevirapine, phenytoin, rifabutin, rifampin, St. John s wort 1 effects OF OCPs, warfarin EMS Use andarrhythmics and benzodiazepines... 

The results showed that mortality among patients treated with the drugs flecainide and encainide (the latter is no longer available) was increased more than twofold compared with those treated with placebo. The mechanism underlying this effect is not known, although an interaction between conduction depression by sodium channel block and chronic or acute myocardial ischemia seems likely. Indirect evidence suggests that other sodium channel blockers may produce a similar effect. 

Although verapamil reduces the clearance of flecainide, this is probably not clinically important (76). However, there is also a pharmacodjmamic interaction, since both drugs increase the PR interval and have additive effects on myocardial contractihty and atrioventricular conduction (77). 

Holtzman JL, Finley D, Mottonen L, Berry DA, Ekholm BP, Kvam DC, McQuinn RL, Miller AM. The pharmacodynamic and pharmacokinetic interaction between single doses of flecainide acetate and verapamil effects on cardiac function and drug clearance. Clin Pharmacol Ther 1989 46(l) 26-32. 

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