Drug reference

Lidocaine

Local Anesthetic

Also known as Lidocaine hydrochloride

START

Confirm ventricular arrhythmia or local anesthesia indication. Baseline ECG, BP, weight. For IV antiarrhythmic: continuous cardiac monitoring. Calculate max local dose based on weight and epinephrine use.

TYPICAL MAX

3 mg/kg IV bolus; 4 mg/min infusion. Local: 4.5 mg/kg (no epi); 7 mg/kg (with epi).

STOP IF

Seizures, severe CNS toxicity, cardiovascular collapse, complete heart block, severe hypotension (SBP <90)

WATCH

ECG (rhythm, QT), BP, CNS status (early toxicity signs: numbness, tinnitus, metallic taste), drug levels if prolonged infusion (therapeutic: 1.5-5 mcg/mL; toxic: >5 mcg/mL)

CDSCO approvedSchedule HATC C01BB01

Dose laddermg/d

Renal dose adjustmenteGFR mL/min/1.73m²

KDIGO 2024 + manufacturer label

Pharmacokineticsplasma · t hours

ONSET: 6min · Immediate (IV); 1-5 min (local)
PEAK: 30min · 20-30 min (local)
t½: 1.8h · 1.5-2 h (normal); 4-6 h (hepatic impairment)
DURATION: 1.5h · 10-20 min (IV); 0.5-2 h (local); 12 h (patch)

EXCRETION

~90% renal (metabolites MEGX, GX); hepatic CYP1A2/CYP3A4; <10%

route + CYP

INTERACTIONS

12 major

SEVERE in our sources

PREGNANCY

FDA PLLR: Animal studies showed no teratogenicity. Widely used in pregnancy for local anesthesia. Large doses may cause fetal bradycardia. Use lowest effective dose.

FDA category + note

Top interactionssee all 12 →

AtenololSevereTextbook-citedKDT 7e · p950
BisoprololSevereTextbook-citedKDT 7e · p950
CarvedilolSevereTextbook-citedKDT 7e · p950
MetoprololSevereTextbook-citedKDT 7e · p950

Available in India

106 branded formulations and 223 fixed-dose combinations. Look up specific brands in the Drugs workspace.

Mechanism

Lidocaine is a class IB antiarrhythmic and amide-type local anesthetic. As an antiarrhythmic, it blocks voltage-gated sodium channels in their open or inactivated state, preferentially affecting ischemic or depolarized tissues (such as in myocardial infarction). It shortens the action potential duration and effective refractory period in Purkinje fibers and ventricular muscle, and suppresses automaticity in ectopic foci. As a local anesthetic, it blocks sodium channels in neuronal membranes, preventing depolarization and propagation of action potentials, resulting in reversible loss of sensation in the targeted area. Unlike ester-type local anesthetics, lidocaine is metabolized by hepatic amidases and does not require plasma pseudocholinesterase.

Indications

Ventricular arrhythmias (PVCs, ventricular tachycardia) — especially post-MIPrevention of ventricular fibrillationLocal anesthesia (infiltration, nerve block, spinal/epidural, topical)Post-herpetic neuralgia (5% patch — Lidoderm)Neuropathic pain (off-label, topical, IV infusion)Status epilepticus (refractory — off-label, IV)Intubation/awake fiberoptic intubation (topical anesthesia)

Dosing

Adult: Antiarrhythmic: 1-1.5 mg/kg IV bolus; repeat 0.5-0.75 mg/kg at 5-10 min intervals (max 3 mg/kg); then 1-4 mg/min IV infusion. Local anesthesia: 1-2% solution; max 4.5 mg/kg (without epinephrine) or 7 mg/kg (with epinephrine). Patch (post-herpetic neuralgia): apply to intact skin over painful area; max 3 patches simultaneously for 12 hours on, 12 hours off.
Pediatric: Antiarrhythmic: 1 mg/kg IV bolus; then 20-50 mcg/kg/min infusion. Local anesthesia: weight-based; max 4.5 mg/kg.
Renal adjustment: No specific adjustment for antiarrhythmic use. Metabolite MEGX may accumulate in severe renal impairment.
Hepatic adjustment: Reduce bolus dose by 50% and infusion rate by 50%. Monitor levels if available.
Geriatric: Reduce dose by 50%. Increased risk of CNS toxicity (confusion, seizures). Monitor drug levels.
Max dose: Antiarrhythmic: 3 mg/kg bolus; 4 mg/min infusion. Local: 4.5 mg/kg (without epi); 7 mg/kg (with epi). Patch: 3 patches q12h.

Pharmacokinetics

Onset

IV: immediate antiarrhythmic effect. Local infiltration: 1-5 minutes. Nerve block: 5-15 minutes.

Peak effect

IV: immediate. Local: 20-30 minutes. Patch: 12-24 hours (steady-state tissue levels).

Duration

IV antiarrhythmic: 10-20 minutes (short — requires infusion). Local infiltration: 0.5-2 hours. Nerve block: 1-3 hours. Patch: 12 hours.

Half-life

~1.5-2 hours (adults); prolonged in hepatic impairment (4-6 hours), CHF (3-4 hours), and elderly.

Bioavailability

Negligible oral (extensive first-pass hepatic metabolism). IV/IM/local: 100%. Transdermal: ~3-5%.

Protein binding

~65-70% (bound to alpha-1-acid glycoprotein; increased in acute phase response).

Metabolism

Extensive hepatic via CYP1A2 (primary — N-deethylation to monoethylglycinexylidide [MEGX] — active metabolite) and CYP3A4 (further metabolism to glycinexylidide [GX] — less active). MEGX has ~80% activity of lidocaine and contributes to toxicity.

Excretion

Renal: ~90% (as metabolites MEGX and GX; <10% unchanged).

Contraindications

Hypersensitivity to lidocaine or other amide local anesthetics
Severe degree of SA, AV, or intraventricular heart block (without pacemaker)
Wolf-Parkinson-White syndrome
History of malignant hyperthermia (relative)
Relative: severe hepatic impairment (reduced metabolism, toxicity risk)
Relative: severe renal impairment (metabolite MEGX accumulation)

Side effects

Common

Local: injection site pain, burning, numbnessCNS: dizziness, lightheadedness, paresthesiasGI: nausea, vomitingCV: hypotension, bradycardiaMuscle twitching

Serious

CNS toxicity (dose-related progression: circumoral numbness → tinnitus → confusion → seizures → respiratory depression → coma)
Cardiovascular collapse (severe hypotension, bradycardia, asystole — usually at higher plasma levels than CNS toxicity)
Methemoglobinemia (rare, especially with topical use in infants or large surface area application)
Allergic reactions (rare with amide-type; more common with ester-type local anesthetics)
Malignant hyperthermia (rare trigger)

Pregnancy & lactation

Pregnancy

FDA PLLR: Animal studies showed no teratogenicity. Widely used in pregnancy for local anesthesia. Large doses may cause fetal bradycardia. Use lowest effective dose.

Lactation

Excreted in breast milk in low concentrations. Compatible with breastfeeding for local anesthesia. Monitor infant if large systemic doses used.