lidocaine (IV)
Brand: Xylocaine
ISMP High Alert Prototype Drug
Drug Class: antiarrhythmic (Class IB) / local anesthetic
Drug Family: antiarrhythmic
Subclass: sodium channel blocker (inactivated state selective)
Organ Systems: cardiovascularcns
Mechanism of Action
Blocks inactivated sodium channels preferentially in ischemic tissue with abnormal automaticity; minimal effect on normal cardiac tissue; also Class IB local anesthetic.
voltage-gated sodium channels (inactivated state)
Indications
- ventricular arrhythmias (VT/VF — second-line to amiodarone in ACLS)
- local/regional anesthesia
- ventricular arrhythmias in setting of acute MI
Contraindications
- Stokes-Adams syndrome
- severe SA/AV block
- allergy to amide local anesthetics
- WPW (accelerates ventricular rate in certain settings)
Adverse Effects
Common
- dizziness
- lightheadedness
- confusion
- perioral numbness
- bradycardia
Serious
- CNS toxicity (seizures)
- cardiovascular collapse
- respiratory arrest
- methemoglobinemia (rare)
Pharmacokinetics (ADME)
| Absorption | <35% oral (extensive first-pass — IV only for arrhythmia) |
| Distribution | large Vd — widely distributed |
| Metabolism | extensive hepatic CYP3A4, CYP1A2 (MEGX active metabolite) |
| Excretion | renal (<10% unchanged) |
| Half-life | 1.5-2 hours |
| Onset | immediate (IV) |
| Peak | immediate (IV) |
| Duration | 10-20 min IV bolus |
| Protein Binding | 60-80% |
| Vd | 1-2 L/kg |
Drug Interactions
| Drug / Agent | Mechanism | Severity |
|---|---|---|
| beta-blockers | reduced hepatic clearance of lidocaine (reduced liver blood flow) | moderate |
| cimetidine | reduces hepatic lidocaine clearance | moderate |
Nursing Considerations
- IV use only for arrhythmia (extensive first-pass oral)
- CNS toxicity precedes cardiac: circumoral numbness → tinnitus → confusion → seizures → cardiac arrest
- Use ideal body weight for loading dose
- Monitor for CNS toxicity during infusion
Clinical Pearls
- CNS toxicity precedes cardiac toxicity in overdose — use sequential symptoms as dose guide
- Amide local anesthetic: not metabolized by plasma cholinesterase (unlike ester-type); cross-allergy within amide class
Safety Profile
Pregnancy use-with-caution
Lactation use-with-caution
Renal Adjustment Required
Hepatic Adjustment Required
TDM Not required
Concordance Terms
Cross-referenced clinical concepts — click any term to see all content where it appears.