Verapamil has been shown to have some efficacy in Table 7. Ongoing Drug Therapy for SVT, Oral Administration* Drug Initial Daily Dose(s) Maximum Total Daily Maintenance Dose Potential Adverse Effects Precautions (Exclude or Use With Caution) and Interactions Beta blockers Atenolol 25 50 mg QD 100 mg QD (reduced dosing in patients with severe renal dysfunction) Hypotension, bronchospasm, bradycardia AV block greater than first degree or SA node dysfunction (in absence of pacemaker) Decompensated systolic HF Hypotension Reactive airway disease Severe renal dysfunction Drugs with SA and/or AV nodal blocking properties Metoprolol tartrate 25 mg BID 200 mg BID Hypotension, bronchospasm, bradycardia AV block greater than first degree or SA node dysfunction (in absence of pacemaker) Decompensated systolic HF Hypotension Reactive airway disease Drugs with SA and/or AV nodal blocking properties Metoprolol succinate (long-acting) 50 mg QD 400 mg QD Hypotension, bronchospasm, bradycardia AV block greater than first degree or SA node dysfunction (in absence of pacemaker) Decompensated systolic HF Hypotension Reactive airway disease Drugs with SA and/or AV nodal blocking properties Nadolol 40 mg QD 320 mg QD (reduced dosage with renal impairment) Hypotension, bronchospasm, bradycardia AV block greater than first degree or SA node dysfunction (in absence of pacemaker) Reactive airway disease Cardiogenic shock Decompensated HF Hypotension Renal dysfunction Drugs with SA and/or AV nodal blocking properties Propranolol 30 60 mg in divided or single dose with long- acting formulations 40 160 mg in divided or single dose with long-acting formulations Hypotension, worsening HF, bronchospasm, bradycardia AV block greater than first degree or SA node dysfunction (in absence of pacemaker) Reactive airway disease Decompensated systolic HF Hypotension Drugs with SA and/or AV nodal blocking properties Nondihydropyridine calcium channel antagonists Diltiazem 120 mg daily in divided or single dose with long- acting formulations 360 mg daily in divided or single dose with long-acting formulations Hypotension, worsening HF in patients with pre-existing ventricular dysfunction, bradycardia, abnormal liver function studies, acute hepatic injury (rare) AV block greater than first degree or SA node dysfunction (in absence of pacemaker) Hypotension Decompensated systolic HF/severe LV dysfunction WPW with AF/atrial flutter Drugs with SA and/or AV nodal blocking properties Diltiazem is a substrate of CYP3A4 (major) and a moderate CYP3A4 inhibitor Apixaban, itraconazole, bosutinib, ceritinib, cilostazol, cyclosporine, everolimus, ibrutinib, idelalisib, ivabradine, lomitapide, olaparib, ranolazine, rifampin, simeprevir (Continued) Page et al 2015 ACC/AHA/HRS SVT Guideline e529 Verapamil 120 mg daily in divided or single dose with long- acting formulations 480 mg daily in divided or single dose with long-acting formulations Hypotension, worsening HF in patients with pre-existing ventricular dysfunction, pulmonary edema in patients with hypertrophic cardiomyopathy, bradycardia, abnormal liver function studies AV block greater than first degree or SA node dysfunction (in absence of pacemaker) Decompensated systolic HF/severe LV dysfunction Hypotension WPW with AF/atrial flutter Verapamil is a moderate CYP3A4 inhibitor and also inhibits P-glycoprotein Contraindicated with dofetilide Itraconazole, bosutinib, ceritinib, cilostazol, colchicine, cyclosporine, everolimus, dabigatran, edoxaban, flecainide, ibrutinib, ivabradine, olaparib, ranolazine, rivaroxaban, rifampin, silodosin, simeprevir, rivaroxaban, rifampin, simvastatin, topotecan, trabectedin, vincristine, grapefruit juice Cardiac glycosides Digoxin Loading: 0.5 mg, with mg doses administered at 6 8-h intervals until evidence of adequate effect (maximum dose 8 12 mcg/ kg over 24 h) 0.25 mg QD Maintenance: 0.125 0.25 mg QD, with dosing based on patient s age, lean body weight, and renal function and drug interactions; occasionally down to 0.0625 mg in cases of renal impairment (trough serum digoxin level 0.5 to Bradycardia, heart block, anorexia, nausea, vomiting, visual changes and cardiac arrhythmias in cases of digoxin toxicity (associated with levels >2 ng/mL, although symptoms may also occur at lower levels) Renal dysfunction WPW with AF/atrial flutter AV block greater than first degree or SA node dysfunction (in absence of pacemaker) Drugs with SA and/or AV nodal blocking properties Reduce dose by 30% 50% when administering with amiodarone and by 50% when administering with dronedarone Monitor digoxin concentrations with verapamil, clarithromycin, erythromycin, itraconazole, cyclosporine, propafenone, flecainide Class Ic antiarrhythmic agents Flecainide 50 mg every 12 h 150 mg every 12 h (PR and QRS intervals should be monitored. 