Lignocaine
Chemical
Tertiary amine amide
Class IB antiarrhythmic
Use
Tx of ventricular arrhythmias, esp. assoc with AMI
Dose
Loading: 1.5mg/kg
Infusion: 1.5mg/kg/hr
To achieve therapeutic plasma level 2 – 6mcg/mL
Route
IV only → extensive 1st pass hepatic metabolism, only 3% oral dose reaches plasma
Onset
15 mins
MoA
- Rapidly blocks active & inactive Na+ channel
→ More effect on cells with long AP (Purkinje, ventricular)
→ Doesn’t really affect atrial cells
→ ∴not used for SVTs
→ ↓refractory period → shortens AP
ECG effects: no ECG ∆ at therapeutic levels
* One of the least cardiotoxic Na channel blockers *
PD
Neuro: reversible neural blockade
Biphasic → CNS excitement → CNS depression
PK
A
–
D
65% PPB
α1 glycoprotein
0.7 – 1.5L/kg
M
Liver, N-dealkylation
E
Metabolites excreted in urine
<10% unchanged
t ½ B = 90 mins
Adverse Effects
- Due to supratherapeutic levels
- Cardiovascular collapse, ↓SVR, ↓FoC, hypotension
- > 600mg → MetHb