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sotalol (Betapace, Sotacor)
Tradename: Betapace. Class III antiarrhythmic agent.
Indications:
1) prevents recurrence of sustained ventricular tachycardia (70%)
2) decreases frequency & duration of non-sustained ventricular tachycardia (40%)
3) prevents recurrence of atrial fibrillation/flutter, but benefits outweighed by proarrhythmic effects
Contraindications:
- avoid in patients with acute heart failure [6]
- avoid in patients with severe LV systolic dysfunction
Dosage:
1) initiate therapy while patient is hospitalized
2) start 80 mg PO BID
3) increase at 2-3 days intervals
4) max 640 mg/day
5) usual maintenance dose is 160-320 mg/day
6) PRN dosing for paroxysmal atrial fibrillation [7]
Dosage adjustment in renal failure:
creatinine clearance dosage interval
30-60 mL/min every 24 hours
10-30 mL/min every 36-48 hours
< 10 mL/min NOT recommended
Tabs: 80, 160, 240 mg.
Pharmacokinetics:
1) bioavailability is 90-100%
2) minimal 1st pass hepatic metabolism
3) not bound to plasma proteins
4) onset of activity is 1-3 hours
5) elimination 1/2life is approximately 7.5 hours
- increased with renal insufficiency
6) duration of action is 12-20 hours
7) excreted unchanged in the urine
Adverse effects:
1) common (> 10%)
- bradycardia, depression, sexual dysfunction
2) less common (1-10%)
- dyspnea, confusion, congestive heart failure, hallucinations, reduced peripheral circulation, anxiety, constipation, diarrhea, dizziness, drowsiness, itching, nausea/vomiting, nightmares, epigastric discomfort, insomnia, weakness, tiredness
3) uncommon (< 1%)
- rash, chest pain, leukopenia, hypotension, diaphoresis, phlebitis, Raynaud's phenomenon, skin necrosis after extravasation, cold extremities, life-threatening ventricular arrhythmias, torsades de pointes, retroperitoneal fibrosis (rare), red & crusted skin
4) cardiac
- prolongation of QT interval
- torsades de pointes, especially with
- hypokalemia
- hypomagnesemia
- diuretic use
- bradyarrhythmias
- prolongs AV conduction
- sinus bradycardia
- contraindicated in patients with sinus bradycardia, 2nd or 3rd degree AV block
- exacerbation of ventricular arrhythmia
- heart failure (3%)
5) non cardiac
- fatigue
- bronchospasm
- may mask symptoms of hypoglycemia
Drug interactions:
1) cardiac effects additive with Ca+2-channel blockers
2) excessive reduction of sympathetic tone when used with:
a) reserpine
b) bretylium
c) guanethidine
3) avoid concurrent use of:
- clonidine, insulin, sulfonylureas, verapamil, class 1A antiarrhythmic agents, digoxin, terfenadine, astemizole, cisapride
Mechanism of action:
1) class III antiarrhythmic agent
2) non-selective beta adrenergic antagonist
3) delays repolarization by blocking K+ channels
Interactions
drug interactions
drug adverse effects (more general classes)
General
antiarrhythmic agent, Group III
non-specific beta-adrenergic receptor antagonist (non-specific beta-blocker)
Properties
MISC-INFO: elimination route KIDNEY 90%
1/2life 12 HOURS
pregnancy-category B
safety in lactation ?
Database Correlations
PUBCHEM correlations
References
- The Pharmacological Basis of Therapeutics, 9th ed.
Gilman et al, eds. Permagon Press/McGraw Hill, 1996
- Harrison's Principles of Internal Medicine, 13th ed.
Isselbacher et al (ed), Companion Handbook, McGraw
Hill, NY, 1994
- Manual of Medical Therapeutics, 28th ed, Ewald &
McKenzie (eds), Little, Brown & Co, Boston, 1995, pg 160-61
- Drug Information & Medication Formulary, Veterans Affairs,
Central California Health Care System, 1st ed., Ravnan et al
eds, 1998
- Kaiser Permanente Northern California Regional Drug
Formulary, 1998
- Medical Knowledge Self Assessment Program (MKSAP) 11, 16.
American College of Physicians, Philadelphia 1998, 2012
- Prescriber's Letter 12(1): 2005
"Pill-in-the-Pocket" Approach to Treating Atrial Fibrillation
Detail-Document#: 210108
(subscription needed) http://www.prescribersletter.com