Procainamide
Chemical
Class IA antiarrhythmic drug
Use
- Acute & chronic SVTs
- Ventricular arrhythmias
Presentation
Clear colourless solution
500mg/mL
Dose
IV: 15mg/kg load (up to 100mg)
Then infusion: 2 – 6mcg/min
Route
PO/IV
Onset
Immediate
MoA
- Blocks Na+ channel = ↓slope Ph 4 depol = suppresses arrhythmias caused by ↑automaticity
- Blocks K+ channel = prolongs AP = prolonged QT
ECG effects
- Prolongs QT
- Broad QRS (slows conduction of impulses)
PD
Negative inotropy
PK
A
–
D
15% PPB
M
Acetylation in liver
E
60% unchanged by kidneys
Adverse Effects
- Drug fever
- Rash
- Agranulocytosis
- Leukopaenia
- Caution with pre-existing prolonged QT