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Lidocaine Parenteral

Tradename: Xylocaine. (lidocaine hydrochloride) Class-IB antiarrhythmic agent. Indications: - antiarrhythmic of choice for ventricular tachycardia (VT) or ventricular fibrillation (VF) that persists following defibrillation & administration of epinephrine - also of benefit in stable VT & wide QRS complex tachycardias of uncertain type - local anesthetic used for anesthesia & analgesia - intravenous analgesia - neuropathic pain when opiates not effective - diabetic neuropathy - post-herpetic neuralgia [8] - used as a last resort for status epilepticus - skin irritation, superficial injury [8] - pruritus, dermatitis - eye surgery - gag reflex Contraindications: 1) 3rd degree heart block with a ventricular escape rhythm 2) Wolf-Parkinson-White syndrome 3) Stokes-Adams syndrome Dosage: Load: -> 1-1.5 mg/kg IV (generally 100 mg), then 0.5 mg/kg every 8-10 min, max 3 mg/kg Caution: - initial bolus should be reduced 50% in patients with: a) heart failure b) shock c) hepatic dysfunction Maintenance: - 1-3 mg/kg/hr, 2 mg in 250 mL D5W (8 mg/mL)* at 1-4 mg/min (7-30 mL/hr) Pediatrics: -> 20-50 ug/kg/min, 10 kg: 3 mL/hr = 40 ug/kg/min * a concentration >= 40 mg/mL is needed for PCA pump because the total volume must be < 3 mL/hour Status epilepticus: 1) bolus: 1 mg/kg followed in 5 min by 0.5 mg/kg 2) infusion: 1-2 mg/min Injection: 0.05% (5 mg/mL) (50 mL) 1% (10 mg/mL) (5, 10, 30, 50 mL) 2% (20 mg/mL) (5 & 50 mL) 4% (40 mg/mL) (5 mL) 20% (200 mg/mL) (5 & 10 mL) 7.5% in 5% dextrose (75 mg/mL) (2 mL) Injection with endotracheal cannulation: (Duo-Trach) 4% (40 mg/mL) (5 mL) (max 2-4 mg/kg) Pharmacokinetics: 1) anesthetic - well absorbed by tissue - faster absorption is associated with a shorter duration of action - addition of epinephrine prolongs the action & localizes the anesthesia - distributes to all tissues - crosses the blood brain barrier - metabolized by the liver - eliminated in the urine - acidification of the urine increases the rate of elimination 2) analgesic - therapeutic level is 2-6 ug/mL for analgesia 3) antiarrhythmic - onset of action 45-90 seconds - duration of action 10-20 minutes - therapeutic level is 1-5 ug/mL - well distributed to all tissue - volume of distribution - decreased in CHF - increased in liver disease - crosses the blood-brain barrier - 1/2life - initial: 7-30 minutes - terminal 1.5-2 hours - metabolized by the liver to MEGX & GX both of which are active metabolites Adverse effects: 1) not common (1-10%) - positional headache, hypotension, shivering 2) central nervous system (< 1%) - confusion, seizures, respiratory arrest, agitation, tremors, psychosis, drowsiness, visual disturbances, lethargy, euphoria, slurred speech, hallucinations 3) cardiac (< 1%) - negative inotropic effects at high doses - arrhythmias - sinus arrest - AV block - increased AV conduction in atrial fibrillation/flutter - hypotension 4) other (< 1%) - urticaria, paresthesias, nausea/vomiting, tinnitus, dyspnea, itching, rash 5) adverse effects by serum blood levels (in parentheses) a) transient adverse effects within therapeutic range - lightheadedness (1 ug/mL) - peri-oral numbness (2 ug/mL) - metallic taste (2-3 ug/mL) - tinnitus (5-6 ug/mL) b) indications for stopping lidocaine infusion - blurry vision (6 ug/mL) - twitching (8 ug/mL) - convulsions (10 ug/mL) - cardiac depression (20-25 ug/mL) Drug interactions: 1) serum 1/2 life of lidocaine is prolonged by: a) propranolol b) cimetidine 2) agents which increase metabolism of lidocaine a) phenobarbital b) phenytoin 3) agents which decrease cardiac output or hepatic blood flow probably decrease lidocaine clearance a) propranolol b) anesthetics c) norepinephrine Laboratory: 1) specimen: a) serum, plasma (heparin, EDTA) b) collect > 30 minutes after a bolus dose c) stable at neutral pH for 1 year at -20 degrees C 2) methods: HPLC, GLC, GC-MS, EIA, FPIA 3) interferences: a) some GLC methods lack sensitivity & specificity b) do NOT collect in serum separator tubes; lidocaine may be extracted by the separator gel Mechanism of action: 1) local anesthetic - amide-type local anesthetic - reversible blocks nerve conduction in all nerve fibers (sensory, motor, autonomic) by decreasing permeability of nerve to Na+ - decreases rate of nerve depolarization - increases threshold of excitability - prevents propagation of action potential - autonomic activity is lost 1st followed by sensory & motor function 2) antiarrhythmic - class 1B antiarrhythmic agent - decreases phase 0 - decreases action potential duration - decreases phase 4 - suppresses automaticity in the His-Purkinje system - suppresses depolarization of the ventricles during diastole

General

lidocaine (Xylocaine) parenteral agent antiarrhythmic agent, Group IB

References

  1. Manual of Medical Therapeutics, 28th ed, Ewald & McKenzie (eds), Little, Brown & Co, Boston, 1995, pg 155, 173
  2. Advanced Cardiac Life Support, The American Heart Association 1994
  3. Harrison's Principles of Internal Medicine, 13th ed. Isselbacher et al (ed), Companion Handbook, McGraw Hill, NY, 1994
  4. Drug Information & Medication Formulary, Veterans Affairs, Central California Health Care System, 1st ed., Ravnan et al eds, 1998
  5. Kaiser Permanente Northern California Regional Drug Formulary, 1998
  6. Clinical Guide to Laboratory Tests, 3rd ed. Teitz ed., W.B. Saunders, 1995
  7. Frederich M., UCLA Multicampus Program in Geriatrics & Gerontology, Syllabus: The Cutting Edge in Palliative Medicine, 2001
  8. Patel BK, Wendlandt BN, Wolfe KS et al. Comparison of two lidocaine administration techniques on perceived pain from bedside procedures: A randomized clinical trial. Chest 2018 Oct; 154:773. PMID: 29698720