Antiarrythmic Dosages

Question 1

Lidocaine

Answer 1

■ 1-1.5 mg/kg IV
■ Infusion 1-4 mg/min (max dose 3 mg/kg)

●	E½T = 1.4-8.0 hours
●	Therapeutic plasma concentration 1-5 ug/mL
○	50% protein binding
○	Hepatic metabolism 
■	Active metabolite, which prolongs E½T

Question 2

Propranolol

Answer 2

●	E½T = 1.4-8.0 hours
●	Therapeutic plasma concentration 1-5 ug/mL
○	50% protein binding
○	Hepatic metabolism 
■	Active metabolite, which prolongs E½T
●	Dose: 
○	1 mg/min (total dose of 3-6 mg) IV or 10-80 mg PO
●	Onset: 
○	2-5 minutes
○	Peak effect 10-15 minutes, duration 3-4 hours
○	E½T = 2-4 hours
●	Highly protein bound 90-95%
●	Therapeutic plasma level 10-30 ng/mL

Question 3

Metoprolol

Answer 3

●	Dose: 
○	Dose 5 mg IV over 5 minutes; max dose 15 mg over 20 minutes
●	Onset: 
○	2.5 minutes
●	Duration: 
○	Half-life 3-4 hours

Question 4

Esmolol

Answer 4

●	Dose: 
○	Dose 5 mg IV over 5 minutes; max dose 15 mg over 20 minutes
●	Onset: 
○	2.5 minutes
●	Duration: 
○	Half-life 3-4 hours
●	Dose: 
○	0.5 mg/kg IV bolus over 1 min, then 50-300 mcg/kg/min
●	Duration:
○	<15 mins

Question 5

Amiodarone

Answer 5

● Dose:
○ Bolus 150-300 mg IV over 2-5 minutes, up to 5 mg/kg, then 1 mg/hr x 6 hrs, then 0.5 mg/hr x 18 hrs
● Prolonged E½ Life = ~29 days (10-100 days)
● Therapeutic plasma level 1.0-3.5 ug/mL
● Extensive protein binding 96%

Question 6

Verapamil

Answer 6

● E½T = 6-8 hours
○ 2.5-10 mg IV over 1-3 minutes (max dose 20 mg)
○ Continuous infusion 5 ug/kg/minute (rare)

Question 7

Diltiazem

Answer 7

○ 5-20 mg IV (0.25-0.35mg/kg) over 2 min.
○ Continuous infusion 10 mg/hour
● E½T = 4-6 hours

Question 8

Adenosine

Answer 8

● Dose:
○ 6 mg IV, rapid bolus, FLUSH AFTER
○ Repeated if necessary after 3 minutes, 6-12 mg IV
● E½T = < 10 seconds

Question 9

Digoxin

Answer 9

○	0.5-1 mg in divided doses over 12-24 hrs
●	Onset of action 30-60 minutes
●	E½T = 36 hours
●	Narrow therapeutic index
○	Therapeutic levels 0.5-1.2 ng/mL
○	Takes ~7 days to reach therapeutic levels
●	Weak protein binding
●	90% Excreted by kidneys

Question 10

Dilatin

Answer 10

○	1.5 mg/kg IV every 5 min. up to 10-15 mg/kg
●	Therapeutic blood levels 10-18 mcg/mL
●	Metabolized by liver
●	Excreted in urine
●	E½T = 24 hours

Question 11

Atropine

Answer 11

○ 0.4 to 1.0 mg IV & repeat as necessary
● Onset less 1 min; duration 30-60 minutes
● Metabolized by liver
● Caution dosing less than 0.4 mg