Lidocaine
XYLOCAINE
What it isSodium channel blocker; local anesthesia, and IV for ventricular arrhythmia.
Why this oneFast onset with a well-defined maximum dose, and the patch treats localized neuropathic pain with negligible systemic exposure.
What limits itSystemic toxicity progresses from perioral tingling to seizures and cardiac arrest — know the weight-based maximum. Hepatic clearance falls in heart failure.
FDA-approved for
- local anesthesia (~1948)
FDA label
Read the full label on DailyMed ↗
| FDA dosing | Population | Start | Target | Max |
|---|---|---|---|---|
| Symptomatic irritated/inflamed mucous membranes of mouth and pharynx | Adults | 15 mL undiluted, swished or gargled, not more often than q3h | 300 mg (<=4.5 mg/kg) per dose; <=8 doses/24h | |
| Oral/pharyngeal topical anesthesia | Children >3 yr (normal lean mass) | Weight/age-based (e.g., 3.7–5 mL in a 50-lb 5-yr-old) | Do not exceed weight-based maximum | |
| Oral topical anesthesia | Infants and children <3 yr | <=1.2 mL to affected area via cotton-tipped applicator; wait >=3h | <=4 doses per 12h |
Renal Undefined
Hepatic Undefined
Max single dose <=4.5 mg/kg (2 mg/lb), not to exceed 300 mg total; space doses >=3h.
Instructions
- For the mouth: swish solution around and spit out.
- For the pharynx: gargle undiluted solution; may be swallowed.
- Measure pediatric doses accurately — overdoses have occurred from inappropriate dosing.
- Adjust dose for patient age, weight, and physical condition.
Cautions
- Dose-related systemic toxicity from high plasma levels or rapid absorption (CNS excitation then depression, convulsions, respiratory arrest)
- Cardiovascular depression: bradycardia, hypotension, cardiovascular collapse, cardiac arrest
- Allergic reactions, incl. to methylparaben/propylparaben excipients
- Risk of overdose in pediatric patients
Adverse reactions
- CNS: lightheadedness, dizziness, tinnitus, blurred/double vision, tremors, convulsions, respiratory depression
- Cardiovascular: bradycardia, hypotension, cardiovascular collapse, cardiac arrest
- Allergic: urticaria, edema, anaphylactoid reactions
Pregnancy No evidence of fetal harm in animal studies; no adequate human studies; use in pregnancy only if clearly needed.
Lactation Undefined
NO BOXED WARNINGS
Principal riskSystemic toxicity: perioral tingling, then seizures
Cost, est. cash$10–$400/month
Generic entry1982
Classes and tags
Clinical profile
Legacy pregnancy categoryC
Defining liabilitySystemic local-anesthetic toxicity causes seizures, conduction block and ventricular dysrhythmia.
Mechanism of action: Lidocaine ballicule
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