Names and pronunciation
(flek-ay′nide) Tambocor
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Drug reference
(flek-ay′nide) Tambocor
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Func. class.: Antidysrhythmic (Class IC)
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Chem. class.: Benzamide derivative
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ACTION: Decreases conduction in all parts of the heart, with greatest effect on the His-Purkinje system, which stabilizes cardiac membrane
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USES: Life-threatening ventricular dysrhythmias, sustained ventricular tachycardia, supraventricular tachydys- rhythmias, paroxysmal atrial fibrillation/ flutter associated with disabling symptoms
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CONTRAINDICATIONS: Hyper- sensitivity, AV bundle branch block, car- diogenic shock Precautions: Pregnancy, breastfeeding, children, geriatric patients, renal/ hepatic disease, HF, respiratory depres- sion, myasthenia gravis, electrolyte abnormalities, atrial fibrillation, sick sinus syndrome, torsades de pointes, MI, bundle branch block, QT prolongation
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Black Box Warning: Cardiac arrhyth- mias, atrial fibrillation, MI Black Box Warning: HF, cardiogenic shock, LVEF <30%: should not be used in these conditions Black Box Warning: Atrial fibrillation: avoid use; risk of ventricular dysrhyth- F mias; use only in life-threatening dys- rhythmias Black Box Warning: Cardiac dysrhyth- mias: discontinue in those with pro- longed QRS >180 ms or prolonged PR >300 ms, monitor for QT prolongation, monitor ECG before and during treatment • Electrolyte imbalances: hypo/hyperka- lemia before administration; correct electrolytes before use • CNS effects: dizziness, confusion, psy- chosis, paresthesias, seizures; product should be discontinued • Monitor renal studies: BUN, creatinine • Flecainide level: monitor level in those with HF or renal failure; peak, trough • Pregnancy/breastfeeding: no well- controlled studies; use only if benefits out- weigh fetal risk; discontinue breastfeeding or product, excreted in breast milk
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SIDE EFFECTS CNS: Headache, dizziness, involuntary movement, confusion, psychosis, rest- lessness, irritability, paresthesias, ataxia, flushing, somnolence, depres- sion, anxiety, malaise, fatigue, asthenia, tremors CV: Hypotension, bradycardia, angina, PVCs, heart block, cardiovascular collapse, arrest, dysrhythmias, HF, fatal ventricular tachycardia, palpitations, QT prolongation, torsades de pointes EENT: Tinnitus, blurred vision, hearing loss, corneal deposits, dry eyes GI: Nausea, vomiting, anorexia, constipa- tion, abdominal pain, flatulence, change in taste, diarrhea GU: Impotence, decreased libido, poly- uria, urinary retention HEMA: Leukopenia, thrombocytopenia INTEG: Rash, urticaria, edema, swelling RESP: Dyspnea, respiratory depression
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INTERACTIONS Increase: QT prolongation—class IA/III antidysrhythmics, some phenothi- azines, β-agonists, local anesthetics, tricyclics, haloperidol, chloroquine, dro- peridol, pentamidine; CYP3A4 inhibitors (amiodarone, clarithromycin, erythro- mycin, telithromycin, troleandomycin), arsenic trioxide, levomethadyl; CYP3A4 substrates (methadone, pimozide, QUE- tiapine, quiNIDine, risperiDONE, ziprasidone) Increase: of both products—propranolol Increase: CV depressant action—β- blockers, disopyramide, verapamil Increase: flecainide level—amiodarone, cimetidine, ritonavir Increase: digoxin level—digoxin Increase or decrease: effect—urinary, alkalinizing agents, acidifying agents Drug/Herb • Do not use with hawthorn Drug/Lab Test Increase: CPK
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TREATMENT OF OVERDOSE: O2, artificial ventilation, ECG, DOPamine for circulatory depression, diazepam or thiopental for seizures, treat ventricular dysrhythmias
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DOSAGE AND ROUTES PSVT/PAT • Adult: PO 50 mg q12hr; may increase q4days by 50 mg q12hr to desired re- sponse, max 300 mg/day Life-threatening ventricular dysrhythmias • Adult: PO 100 mg q12hr; may increase by 50 mg q12hr q4days, max 400 mg/day Renal dose • Adult: PO CCr <35 mL/min, 100 mg daily or 50 mg bid initially
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Available forms: Tabs 50, 100, 150 mg
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Administer: PO route • Reduced dosage as soon as dysrhyth- mia is controlled • May give with meals for GI upset • May adjust dose q4days • Adjust dosage at intervals of ≥4 days (approximate plateau effects); however, longer intervals are needed in patients with renal or hepatic impairment • Frequent serum drug concentration monitoring is required for patients with severe renal (CrCl <35 mL/min) or he- patic disease and may also be helpful in patients with HF or in patients with mod- erate renal disease • Monitoring of flecainide serum con- centrations is strongly recommended in patients receiving amiodarone therapy
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Assess:
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Evaluate: • Therapeutic response: decreased dys- rhythmias
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CLINICAL CONSIDERATIONS
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Patient and caregiver information: • To change position slowly from lying or sitting to standing to minimize orthostatic hypotension • To take as prescribed; not to skip or double dose, to take missed dose as soon as remembered within 6 hr of next dose • To avoid hazardous activities that require alertness until response is known • To carry emergency ID with disorder, medications taken • To notify all health care providers of treatment, that follow-up will be needed • To report new or worsening cardiac symptoms (chest pain, trouble breathing, sweating)
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PHARMACOKINETICS Peak 3 hr, half-life 12-27 hr, metabolized by liver, excreted unchanged by kidneys (10%), excreted in breast milk
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• Adult: PO 50 mg q12hr; may increase q4days by 50 mg q12hr to desired re- sponse, max 300 mg/day Life-threatening ventricular dysrhythmias
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• Adult: PO 100 mg q12hr; may increase by 50 mg q12hr q4days, max 400 mg/day Renal dose
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• Adult: PO CCr <35 mL/min, 100 mg daily or 50 mg bid initially
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