Class Ia | | | | |
Quinidine gluconate (SR) | - 250 mg PO q 8 h
- ↑ By 250 mg doses if QTc <460 ms
- ↓ Dose if QTc ≥500 ms
- Discontinue if QTc ≥550 ms
| ↓ Initial dose 50% + ↑ dosing interval to q 12 h in renal failure | Diarrhea, stomach cramps, tinnitus; torsade de pointes VT | |
Procainamide SR | - 250 mg PO q 6 h
- ↑ By 250 mg increments if QTc <460 ms
- Maximum dose 1 g PO 1 6 h
- ↓ Dose if QTc ≥500 ms
- Discontinue if QTc >550 ms
| Metabolism depends on rate of acetylation; the active metabolite NAPA accumulates in fast acetylators and in renal failure; monitor procainamide + NAPA levels and keep sum <80 μM: monitor ECG intervals | Agranulocytosis, rash, fever, SLE syndrome, torsade de pointes VT |
Amiodarone, cimetidine, propranolol may increase procainamide concentrations |
Procainamide IV | - 750–1000 mg loading
- 15–17 mg/kg at 20 mg/min; maintenance 1–4 mg/min
| | Hypotension | |
Disopyramide | - 100 mg PO q 8 h
- SR 150–250 mg q 12 h
- ↑ By 100-mg increments if QTc <460 ms
- Maximum dose 300 mg PO q 8 h dose if QTc ≥500 ms
- Discontinue if QTc ≥550 ms
| ↓ Initial dose 50% and ↑ dosing interval q 12 h in renal failure | Urinary retention, blurred vision, constipation, dry month, worsening heart failure, torsade de pointes VT | |
Class Ib | | | | |
Lidocaine IV | 1.5 mg/kg loading; 1–4 mg/min maintenance | ↓ dose in CHF | Numbness, paresthesia, slurred speech, altered consciousness. |
Propranolol, metoprolol, cimetidine, increase lidocaine concentrations |
Mexiletine | 150 mg–300 mg PO q 8 h | | Nausea, stomach cramps, tremor, blurred vision, ataxia, confusion. |
Cimetidine, quinidine, increase mexiletine concentrations |
Class Ic | | | | |
Flecainide | - 50 mg PO q 12 h
- ↑ by 25–50-mg increments
- Maximum dose 200 mg PO q 12 h
- ↓ Dose if QRS prolonged >20% from baseline
| ↓ Initial dose 50% in renal failure; titrate dose based on QRS intervals. | Tremor, blurred vision, headache, ataxia, CHF, VT proarrhythmia |
Amiodarone, cimetidine, propranolol, quinidine, increase flecainide concentrations |
Propafenone | - 150 mg PO q 8–12 h
- Maximum dose 300 mg PO q 8 h
- ↓ Dose if QRS prolonged >20% from baseline
| - ↓ Initial dose 50% in renal and hepatic failure and ↑ dosing interval to q 12 h
- Active metabolites accumulate in rapid metabolizers; monitor QRS duration carefully
| Constipation, dizziness, headache, metallic taste, exacerbation of asthma, VT proarrhythmia | ↓ Digoxin dose by 25%–50%; cimetidine and quinidine increase propafenone concentrations |
Class II | | | | |
Atenolol | 50–200 mg PO daily | - Caution in patients with CHF or bronchiospastic lung disease
- Monitor carefully in diabetic patients
- ↓ Dose in moderate to severae renal insufficiency
| Bradycardia, hypotension, dyspnea, fatigue, depression | |
Bisoprolol | 2.5–10 mg PO bid | As per atenolol
| As per atenolol
| As per atenolol
|
Carvedilol | 3.25–50 mg PO bid | - As per atenolol
- Titrate dose every 1–2 wk to achieve maximum tolerated dose
| As per atenolol
| As per atenolol
|
Metoprolol | - 5–15 mg IV
- 25–400 mg PO bid
| As per atenolol
| As per atenolol
| As per atenolol
|
Nadolol | 20–160 mg PO daily | As per atenolol and ↓ dose in moderate to severe renal insufficiency | As per atenolol
| As per atenolol
|
Propranolol | - 1–2 mg IV q 2–4 min
- PRN × 4–5 doses
- 20–80 mg PO bid/tid
| As per atenolol
| As per atenolol
| As per atenolol
|
Class III | | | | |
Amiodarone | - For AF: 200 mg PO tid × 2 wk, then 200 mg/d
- For VT: accelerated loading dose in hospital 400 mg PO tid × 10–14 d, then 400 mg PO bid × 7 d, then 300–400 mg PO daily
| Avoid high loading dose in setting of sinus bradycardia (HR <50 beats/min) | Pulmonary toxicity, CNS effects, hyper-/hypothyroidism, photosensitivity, corneal deposits, hepatic toxicity. | |
Amiodarone IV | 150–300 mg IV over 20–30 min, then 0.5–1 mg/min; repeat boluses may be required | May cause hypotension | | |
Dofetilide | 125–500 μg PO bid | ↓ Dose if QT interval prolongs after first dose by 15%; discontinue if QTc ≥550 ms | Headache; torsade de pointes VT |
Cimetidine, verapamil, ketoconazole, trimethoprim alone or in combination with sulfamethoxazole
|
Sotalol | - 80 mg PO q 12 h
- ↑ By 80-mg increments if QTc <460 ms
- Maximum dose 240 mg PO q 12 h
- ↓ Dose if QTc ≥500 ms; discontinue if QTc ≥550 ms
| - ↓ Initial dose in renal failure
- ↓ Initial dose to 40 mg PO q 12 h in the elderly
| Torsade de pointes VT, hypotension, bradycardia, wheezing; caution in CHF and bronchospastic lung disease |
Digoxin/verapamil/other β blockers may cause AV block, bradycardia |
Class IV | | | | |
Diltiazem | - 0.25–0.35 mg/kg IV
- 120–480 mg PO daily/bid
| Caution in patients with CHF | Bradycardia, hypotension, peripheral edema | β Blockers, digoxin, amiodarone
|
Verapamil | - 5–15 mg IV
- 80 mg PO tid; maximum dose 120 mg qid or 240 mg bid
| Caution in patients with CHF | Bradycardia, hypotension, constipation, flushing | β Blockers, digoxin, amiodarone
|
Digoxin | 0.0625–0.25 mg PO daily | ↓ Dose in renal failure | Arrhythmias, visual disturbance, nausea, vomiting | β Blockers; calcium channel blockers, quinidine, propafenone, procainamide, amiodarone. |
Digoxin IV | 0.25–1.0 mg IV over 20–30 min | | | |