Trade Names:Norpace- Capsules 100 mg- Capsules 250 mg as phosphate
Trade Names:Norpace CR- Capsules, extended-release 100 mg- Capsules, extended-release 150 mg as phosphateRythmodan (Canada)Rythmodan-LA (Canada)
Decreases rate of diastolic depolarizations rate; decreases upstroke velocity; increases action potential duration; prolongs refractory period.
Rapidly and almost completely absorbed. T max is 2 h.Extended release (ER) (300 mg dose)
C max approximately 3.23 mcg/mL. T max is approximately 2.5 h.
50% to 65% protein bound (concentration dependent). Excreted in human milk.
The t ½ is approximately 6.7 h (IR) and approximately 11.65 h (ER). Approximately 50% excreted unchanged in the urine and approximately 30% as metabolites.
Because more than 50% excreted in the urine, dosage reduction recommended.Hepatic Function Impairment
The t ½ increased. Dosage reduction recommended.Heart failure
T max and C max are increased. The t ½ is also prolonged.Heart disease
The t ½ slightly prolonged to approximately 7.8 h.
Suppression and documented prevention of ventricular arrhythmias considered to be life threatening.
Treatment of paroxysmal supraventricular tachycardia.
Cardiogenic shock; preexisting second- or third-degree AV block (if no pacemaker present); congenital QT prolongation; sick sinus syndrome; known hypersensitivity to the drug.
PO 400 to 800 mg/day. Divide total daily dose and administer every 6 h in IR form or every 12 h in ER form. If patient weighs less than 50 kg, give 400 mg/day in divided doses; administer every 6 h for IR or every 12 h for ER.Children (12 to 18 yr of age)
PO 6 to 15 mg/kg/day in divided doses.Children (4 to 12 yr of age)
PO 10 to 15 mg/kg/day in divided doses.Children (1 to 4 yr of age)
PO 10 to 20 mg/kg/day in divided doses.Children (younger than 1 yr of age)
PO 10 to 30 mg/kg/day in divided doses.Rapid Control Of Ventricular Arrhythmia
PO Initial loading dose 300 mg IR (200 mg for less than 50 kg), followed by appropriate maintenance dose.Severe Refractory Ventricular Tachycardia
PO May give up to 400 mg every 6 h.With Cardiomyopathy or Cardiac Decompensation
PO Limit initial dose 100 mg every 6 to 8 h.Renal/Hepatic Function ImpairmentAdults
PO For moderate renal insufficiency (Ccr greater than 40 mL/min) or hepatic insufficiency, give 400 mg in divided doses as 100 mg every 6 h for IR, or 200 mg every 12 h for ER. In severe renal insufficiency, administer the immediate-release form as follows with or without an initial loading dose of 150 mg. Ccr 30 to 40 mL/min: give 100 mg every 8 h. Ccr 15 to 30 mL/min: give 100 mg every 12 h. Ccr less than 15 mL/min: give 100 mg every 24 h.
Store capsules at controlled room temperature (59° to 86°F). Store extemporaneous suspension in refrigerator (36° to 46°F). Discard any unused suspension after 30 days.
May cause widened QRS and prolonged QT.Beta-blockers (eg, metoprolol, propranolol)
Both agents may depress cardiac output, increasing the risk of side effects (eg, sinus bradycardia).Cisapride, quinolone antibiotics (eg, sparfloxacin), thioridazine, ziprasidone
Possible additive prolongation of the QT interval, increasing the risk of life-threatening cardiac arrhythmias, including torsades de pointes.CYP3A4 inhibitors (eg, azole antifungal agents [ketoconazole], macrolide antibiotics [eg, clarithromycin, erythromycin])
Disopyramide plasma levels may be elevated. Arrhythmias, increased QTc intervals, and hypoglycemia have been reported with coadministration of erythromycin or clarithromycin and disopyramide.Hydantoins
May decrease disopyramide serum levels, t ½ , and bioavailability.Quinidine
Disopyramide levels may be elevated, increasing the risk of toxicity, while quinidine levels may be reduced, decreasing the therapeutic response to quinidine.Rifamycins (eg, rifampin)
Disopyramide plasma levels may be decreased while levels of the active metabolite may be increased. The clinical importance of this interaction has not been determined.Verapamil
Do not administer disopyramide within 48 h before or 24 h after verapamil.
None well documented.
Cardiac conduction disturbances, increased CHF, hypotension, syncope (1% to 3%).
Dizziness, fatigue, headache, malaise (3% to 9%); nervousness (1% to 3%).
Generalized rash/dermatoses, itching (1% to 3%).
Blurred vision, dry nose, dry eyes, and dry throat (3% to 9%).
Dry mouth (32%); constipation (11%); nausea, pain/bloating/gas (3% to 9%); anorexia, diarrhea, vomiting (1% to 3%).
Urinary hesitancy (14%); urinary frequency, urgency, urinary retention (3% to 9%); impotence (1% to 3%).
Elevated cholesterol/triglycerides, hypokalemia (1% to 3%).
Edema, weight gain (1% to 3%); hypoglycemia.
Muscle weakness (3% to 9%).
Shortness of breath (1% to 3%).
Aches, pain (3% to 9%); chest pain (1% to 3%).
Because of the known proarrhythmic properties of disopyramide and the lack of evidence of improved survival for any antiarrhythmic drug in patients without life-threatening arrhythmias, reserve the use of disopyramide for patients with life-threatening ventricular arrhythmias.
Ensure that IOP is measured in patient with family history of glaucoma before therapy is initiated. Ensure that patient with atrial flutter or fibrillation is adequately digitalized before initiating therapy with disopyramide to prevent accelerated ventricular rates.
Category C .
Excreted in breast milk.
Safety and efficacy not established. See Route/Dosage.
Use with caution because of the greater frequency of decreased hepatic, renal, or cardiac function, and concomitant diseases or other drug therapy.
Because disopyramide has anticholinergic activity, do not use disopyramide in patients with glaucoma, urinary retention, or benign prostatic hypertrophy.
Use with extreme caution in patients with urinary retention, glaucoma, or myasthenia gravis.
Patients with myocarditis or other cardiomyopathy may develop significant hypotension.
Use with caution in patients with bundle branch block, sick sinus syndrome, or Wolff-Parkinson-White syndrome.
Reduce dose if first-degree block occurs; drug may need to be discontinued if heart block continues.
May cause or aggravate CHF or produce severe hypotension, especially in patients with depressed systolic function.
In rare cases may produce significant lowering of blood glucose.
Disopyramide may be ineffective in hypokalemia and have enhanced toxicity in hyperkalemia.
Widening of the QRS complex more than 25% may occur.
Prolongation of the QT interval and worsening of arrhythmia may occur.
Loss of consciousness, cardiac arrhythmias, loss of spontaneous respiration, death.
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