Details About Overdose or Poisoning Generic Salt :: Bretylium
Drug Pharmacology ::
I. Pharmacology. Bretyliumis a quaternary ammonium compound that is an effective type IIIantifibrillatory drug and also suppresses ventricular ectopic activity.It increases the threshold for ventricular fibrillation and reduces thedisparity in action potential duration between normal and ischemictissue, which is believed to abolish the boundary currents responsiblefor reentrant arrhythmias. Its pharmacologic actions are complex.Initially, norepinephrine is released from sympathetic neurons; this isfollowed by a block of further norepinephrine release. In addition,norepinephrine uptake is inhibited at adrenergic neurons. The result isa transient increase in heart rate, blood pressure, and cardiac outputthat may last from a few minutes to 1 hour. Subsequent adrenergicblockade produces vasodilation, which may result in hypotension.
Drug Indications ::
Prophylaxis and treatment of ventricular fibrillation. Bretylium may be particularly effective in hypothermic patients.
Ventricular tachycardia resistant to other antiarrhythmic agents. However, it has not been proved beneficial for drug- or chemical-induced ventricular dysrhythmias.
Drug Contra-Indications ::
Usewith extreme caution in patients with intoxication by digitalis,chloral hydrate, or halogenated hydrocarbons, because the initialrelease of catecholamines may aggravate arrhythmias.
Usewith extreme caution in patients with arrhythmias caused byintoxication with cyclic antidepressants or type Ia or type Icantiarrhythmic agents because of additive cardiac depression.
Use with extreme caution in patients with severe pulmonary hypertension or aortic stenosis.
Not recommended for children under 12 years old.
Drug Adverse Effects ::
IV. Adverse effects
Hypotension (both supine and orthostatic).
Nausea and vomiting from rapid intravenous administration.
Transient hypertension and worsening of arrhythmias may be caused by initial catecholamine release.
Use in pregnancy. FDAcategory C (indeterminate). However, this does not preclude its acute,short-term use for a seriously symptomatic patient (see Table III–1).
Drug Lab Interactions ::
Drug or laboratory interactions
The pressor effect of sympathomimetic amines may be enhanced with initial catecholamine release.
Cardiac-depressant effects may be additive with other antiarrhythmic drugs, particularly type Ia and type Ic drugs.
Drug Dose Management ::
Dosage and method of administration
For ventricular fibrillation,give 5 mg/kg IV over 1 minute (in addition to cardiopulmonaryresuscitation and defibrillation). If this is not effective,administration may be repeated with 10 mg/kg.
For ventricular tachycardia,give adults and children older than 12 years 5–10 mg/kg IV over 8–10minutes or IM, repeated as necessary at 15-minute intervals to amaximum dose of 30 mg/kg; repeat every 6 hours as needed.
The continuous infusion rate after the loading dose is 1–2 mg/min (children 12 years old, 20–30 mcg/kg/min).
Drug Chemical Formulations ::
Parenteral. Bretyliumtosylate (various), 50 mg/mL: 10-mL ampules, vials, and syringes; 500(2 mg/mL) and 1000 (4 mg/mL) mg premixed in 250-mL 5% dextrosesolutions.
The suggested minimum stocking level to treat a 70-kg adult for the first 24 hours is six 10-mL vials.