Anti Arrhythmic Drug Dosage

1. Adenosine

Dosage for SVT : 1st 3-6 mg , if not effective within 1-2min
2nd 6 mg , if not effective within 1-2min
3rd 12 mg. ( Consider other drugs / methods if still not effective)

Method of administration

Rapid intravenous - over 1-2 seconds, via peripheral line

Site as proximal as possible to trunk (not in lower arm, hand, lower leg, or foot); follow each bolus with normal saline flush.

Follow each I.V. bolus of adenosine with normal saline flush.

In adults may be administered via a central line at lower doses (ie,initial dose: 3 mg).

Use

SVT including that associated with accessory bypass tracts (WPW), appropriate vagal maneuvers should be attempted prior to adenosine administration;

not effective in atrial flutter, atrial fibrillation, or ventricular tachycardia

2. Verapamil

Dosage for SVT : I.V.: 1st dose 2.5-5 mg (over 2 minutes);
2nd dose 5-10 mg (~0.15 mg/kg) may be given 15-30min
after the initial dose if patient tolerates, but does
not respond to initial dose; max total dose: 20 mg

Oral : 120 -480 mg/day in divided doses

Contraindications and Precautions:

Try to avoid using verapamil in the following condition;

heart failure, hypotension (systolic pressure <90 mm Hg) or cardiogenic shock; sick sinus syndrome (except in patients with a functioning artificial pacemaker); second- or third-degree AV block (except in patients with a functioning artificial pacemaker); accessory bypass tract (WPW, Lown-Ganong-Levine syndrome)

3. Amiodarone.

IV Amiodarone Loading : 300mg / 100cc D5% in ½ - 1hr, then
Maintenance: 900mg/ 1 OD5% in 23 hrs or till arrhythmia is controlled
(10-20mg/kg/day)

Or infusion @ 0.5 mg/min ( utilizing concentration of 1-6 mg/mL)

* A fast I.V.: 150 mg supplemental doses in 100 mL D5% over 10 minutes can be given in cases of breakthrough VF or VT

Contraindications and Precautions:

Severe liver disease, porphyria, thyroid dysfunction, Correct electrolyte disturbances, especially hypokalemia or hypomagnesemia, prior to use and throughout therapy.
Prolonged QT syndromes.

4. Digoxin.

Dosage for Atrial Fibrilation

Initial: Total digitalizing dose: Give 1/2 of the total digitalizing dose (TDD) in the initial dose, then additional fraction in 4-8 hrs interval. Obtain ECG 6 hours after each dose to assess potential toxicity.

Oral: 0.75-1.5 mg
I.V. or I.M.: 0.5-1 mg

Example; Digoxin 0.5mg stat followed by another 0.25mg x 2doses in 6 hrs interval

Daily maintenance dose: Give once daily
Oral: 0.125-0.5 mg
I.V. or I.M.: 0.1-0.4 mg

Contraindications and Precautions:

ventricular tachycardia or fibrillation; Wolff-Parkinson-White syndrome and atrial fibrillation concurrently, Correct hypokalemia and hypomagnesemia before initiating therapy, Use with caution in acute MI (within 6 months). Adjust doses in renal impairment and when verapamil or amiodarone are added to a patient on digoxin.




5. Lignocaine.

Dosage for Ventricular Tachycardia / fibrilation:

I.V.: 1-1.5 mg/kg bolus over 2-3 minutes;
may repeat doses of 0.5-0.75 mg/kg in 5-10 minutes up to a total of 3 mg/kg;

Continuous infusion: 1-4 mg/minute

Infusion rates: 2 g/250 mL D5W (infusion pump should be used):

1 mg/minute: 7 mL/hour
2 mg/minute: 15 mL/hour
3 mg/minute: 21 mL/hour
4 mg/minute: 30 mL/hour

E.T. (loading dose only): 2-2.5 times the I.V. dose

Contraindications and Precautions:

Intravenous: Use cautiously in hepatic impairment, any degree of heart block, Wolff-Parkinson-White syndrome, CHF, marked hypoxia, severe respiratory depression, hypovolemia, history of malignant hyperthermia, or shock.

Increased ventricular rate may be seen when administered to a patient with atrial fibrillation. Correct any underlying causes of ventricular arrhythmias. Monitor closely for signs and symptoms of CNS toxicity. The elderly may be prone to increased CNS and cardiovascular side effects. Reduce dose in hepatic dysfunction and CHF.