Names and pronunciation
(pro-paff′e-nown) Rythmol , Rythmol SR
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Drug reference
(pro-paff′e-nown) Rythmol , Rythmol SR
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Func. class.: Antidysrhythmic (class IC)
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ACTION: Slows conduction velocity; reduces membrane responsiveness; inhibits automaticity; increases ratio of effective refractory period to action potential duration; β-blocking activity
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USES: Sustained ventricular tachycardia, atrial fibrillation (single dose), paroxysmal supraventricular tachycardia (PSVT) prophylaxis, supraventricular dysrhythmias
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Unlabeled uses: Wolff-Parkinson-White (WPW) syndrome
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CONTRAINDICATIONS: 2nd/3rd- degree AV block, right bundle branch block, cardiogenic shock, hypersensitivity, bradycardia, uncontrolled HF, sick-sinus syndrome, marked hypotension, bron chospastic disorders, electrolyte imbal ance, Brugada syndrome Precautions: Pregnancy, breastfeed- ing, children, geriatric patients, HF, hypo/hyperkalemia, nonallergic bron- chospasm, renal/hepatic disease, hema- tologic disorders, myasthenia gravis, COPD
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Black Box Warning: Recent MI, cardiac arrhythmias, QT prolongation, torsades de pointes Black Box Warning: QT/PR prolonga- tion: ECG or Holter monitor before and during therapy Black Box Warning: HF: dyspnea, jugu- lar venous distention, crackles, edema in extremities, I&O ratio; check for decreas- ing output; daily weight • CBC, ANA titer, LFTs • Chest x-ray, pulmonary function test during treatment • Lung fields; bilateral crackles, dys- pnea, peripheral edema, weight gain; jugular venous distention may occur in patient with HF • Toxicity: fine tremors, dizziness, hy- potension, drowsiness, abnormal heart P rate • Pregnancy/breastfeeding: use only if benefits outweigh fetal risk; do not breastfeed, excreted in breast milk
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SIDE EFFECTS CNS: Headache, dizziness, abnormal dreams, syncope, confusion, seizures, insomnia, tremor, anxiety, fatigue CV: Supraventricular dysrhythmia, ven- tricular dysrhythmia, bradycardia, pro- dysrhythmia, palpitations, AV block, intra- ventricular conduction delay, AV dissociation, hypotension, chest pain, asystole EENT: Blurred vision, altered taste, tinnitus GI: Nausea, vomiting, constipation, dys- pepsia, cholestasis, abnormal hepatic studies, dry mouth, diarrhea, anorexia HEMA: Leukopenia, agranulocytosis, thrombocytopenia, granulocytopenia, anemia, bruising INTEG: Rash RESP: Dyspnea
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INTERACTIONS Increase: propafenone effects—CYP1A2, CYP2D6, CYP3A4 inhibitors (protease inhibitors, quiNINE, PARoxetine, saqui- navir, erythromycin, azole antifungals, sertraline, tricyclics) Increase: QT prolongation—other class IA/IC antidysrhythmics, arsenic trioxide, chloroquine, clarithromycin, droperidol, erythromycin, haloperidol, methadone, pentamidine, chlorproMAZINE, mesorida- zine, thioridazine Increase: anticoagulation—warfarin Increase: CNS effects—local anesthetics Increase: digoxin level—digoxin Increase: β-blocker effect—proprano- lol, metoprolol Increase: cycloSPORINE levels— cycloSPORINE Decrease: propafenone effect— rifAMPin, cimetidine, quiNIDine Drug/Food Increase: propafenone effect—grape- fruit juice Drug/Herb Decrease: propafenone effect—St. John’s wort Drug/Lab Test Increase: CPK, Hct, HB Decrease: WBC, platelets
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TREATMENT OF OVERDOSE: O2, artificial ventilation, defibrillation ECG; administer DOPamine for circulatory depression, diazePAM or thiopental for seizures, isoproterenol See Appendix B HIGH ALERT
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DOSAGE AND ROUTES PSVT • Adult: PO 150 mg q8hr; allow 3-4 day interval before increasing dose, max 900 mg/day Atrial fibrillation • Adult: PO 450 or 600 mg as single dose; SR 225 mg q12hr, may increase to 325 q12hr, max 425 mg q12hr
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Available forms: Tabs 150, 225, 300 mg; SR cap 225, 325, 425 mg
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Administer: • Do not break, crush, or chew tabs; swallow whole • To hospitalized patients because heart monitoring is required • After hypo/hyperkalemia is corrected • With dosage adjustment q3-4days • Without regard to meals
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Assess: • GI status: bowel pattern, number of stools
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Evaluate: • Therapeutic response: absence of ven- tricular dysrhythmias; decreasing recur- rence of PAF, PSVT
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CLINICAL CONSIDERATIONS
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Patient and caregiver information: • To avoid hazardous activities until re- sponse is known • To report fever, chills, sore throat, bleeding, SOB, chest pain, palpitations, blurred vision • To take tab with food; alterations in taste sensation may occur; not to use with grapefruit juice or St. John’s wort • To carry emergency ID identifying medication and prescriber • To avoid abrupt discontinuation of product; to take as prescribed; not to miss, double doses • Pregnancy/breastfeeding: to notify prescriber if pregnancy is planned or sus- pected; not to breastfeed
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PHARMACOKINETICS Peak 3-8 hr, half-life 2-10 hr, poor metabolizers 10-32 hr; metabolized in liver; excreted in urine (metabolite)
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• Adult: PO 150 mg q8hr; allow 3-4 day interval before increasing dose, max 900 mg/day Atrial fibrillation
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• Adult: PO 450 or 600 mg as single dose; SR 225 mg q12hr, may increase to 325 q12hr, max 425 mg q12hr
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