What Is Lidocaine and How Does It Work?
Lidocaine is used to relieve nerve pain after shingles (infection with the herpes zoster virus). This type of pain is called post-herpetic neuralgia. Lidocaine helps to reduce sharp/burning/aching pain as well as discomfort caused by skin areas that are overly sensitive to touch. Lidocaine belongs to a class of drugs known as local anesthetics. It works by causing a temporary loss of feeling in the area where you apply the patch.
Lidocaine is available under the following different brand names: Lidocaine CV, and Lidopen.
What Are Dosages of Lidocaine?
Dosage of Lidocaine:
Adult and Pediatric Dosage Forms and Strengths
Infusion solution in D5W
- 100 mg/100mL
- 200 mg/100mL
- 400 mg/100mL
- 800 mg/100mL
Injectable solution
- 10 mg/100mL
- 20 mg/100mL
Dosing Considerations – Should be Given as Follows:
Adult
- 1-1.5 mg/kg slow intravenous (IV) bolus over 2-3 minutes
- May repeat doses of 0.5-0.75 mg/kg in 5-10 minutes up to 3 mg/kg total
- Continuous infusion: 1-4 mg/min intravenously (IV)
- If IV is not feasible may use intraosseous infusion (IO) or via an endotracheal tube (ET)
- Monitor: ECG
Pediatric
- Bolus: 0.5-1 mg/kg IV/IO/ET, not to exceed 100 mg; follow with continuous infusion; if the delay between bolus and start of infusion is more than 15 minutes, administer a second bolus every
- 5-10 minutes to 5 mg/kg, THEN
- Continuous infusion: 20-50 mcg/kg/min intravenous (IV)
- Monitor ECG
Regional Anesthesia (IV)
- 4 mg/kg
Paracervical Block
- 200 mg per 90 minutes in obstetric and non-obstetric patients
Other Indications and Uses
- Acute management of ventricular arrhythmias (cardiac surgery, acute MI)
- Off-label: Pediatrics with premature ventricular beats during cardiac arrest
What Are Side Effects Associated with Using Lidocaine?
Common Side effects of Lidocaine include:
- Low blood pressure (hypotension)
- Swelling (edema)
- Redness at the injection site
- Small red or purple spots on the skin
- Skin irritation
- Constipation
- Nausea
- Vomiting
- Confusion
- Dizziness
- Headache
- Numbness and tingling
- Drowsiness
- Tremor
- Irritation symptoms (topical products); i.e., redness, swelling
Serious side effects of lidocaine include:
- Cardiac arrest
- Abnormal heartbeat
- Methemoglobinemia
- Seizures
- Severe allergic reactions (anaphylaxis)
- Malignant hyperthermia
This document does not contain all possible side effects and others may occur. Check with your physician for additional information about side effects.
What Other Drugs Interact with Lidocaine?
If your doctor has directed you to use this medication, your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them. Do not start, stop, or change the dosage of any medicine before checking with your doctor, health care provider, or pharmacist first.
Severe Interactions of lidocaine include:
- bupivacaine liposome
- dofetilide
- eliglustat
- flibanserin
- lomitapide
Serious Interactions of lidocaine include:
- axitinib
- bosutinib
- cobimetinib
- eliglustat
- fentanyl
- fentanyl intranasal
- fentanyl iontophoretic transdermal system
- fentanyl transdermal
- fentanyl transmucosal
- fluvoxamine
- fosamprenavir
- ivabradine
- ivacaftor
- mefloquine
- naloxegol
- olaparib
- pefloxacin
- phenytoin
- pimozide
- pomalidomide
Lidocaine has moderate interactions with at least 62 different drugs.
Lidocaine has mild interactions with at least 28 different drugs.
This information does not contain all possible interactions or adverse effects. Therefore, before using this product, tell your doctor or pharmacist of all the products you use. Keep a list of all your medications with you, and share this information with your doctor and pharmacist. Check with your health care professional or doctor for additional medical advice, or if you have health questions, concerns, or for more information about this medicine.
What Are Warnings and Precautions for Lidocaine?
Warnings
- This medication contains lidocaine
- Do not take Lidocaine CV or Lidopen if you are allergic to lidocaine or any ingredients contained in this drug
- Keep out of reach of children
- In case of overdose, get medical help or contact a Poison Control Center immediately
Contraindications
- Hypersensitivity to lidocaine or amide-type local anesthetic
- Adams-Stokes syndrome, SA/AV/intraventricular heart block in the absence of an artificial pacemaker
- CHF, cardiogenic shock, 2nd and 3rd-degree heart block (if no pacemaker is present), Wolff-Parkinson-White Syndrome
Effects of Drug Abuse
- No information available
Short-Term Effects
- See "What Are Side Effects Associated with Using Lidocaine?"
Long-Term Effects
- See "What Are Side Effects Associated with Using Lidocaine?"
Cautions
- Constant monitoring with an EKG is essential to the proper administration of lidocaine IV; discontinue immediately with signs of excessive depression of cardiac conductivity (e.g., PR interval prolongation, QRS interval widening, arrhythmia exacerbation)
- Lidocaine effects increased by beta-blockers and cimetidine
- Not recommended as prophylaxis in acute myocardial infarction (MI) (controversial)
- Liver disease, CHF, bradycardia, Wolff-Parkinson-White syndrome, marked hypoxia, severe respiratory depression, hypovolemia, incomplete heart block
- Good for automatic and re-entrant arrhythmias, not PSVTs
Pregnancy and Lactation
- Lidocaine may be acceptable to use during pregnancy
- Either animal studies show no risk but human studies are not available or animal studies showed minor risks and human studies done and showed no risk
- Lidocaine crosses into breast milk; use caution if breastfeeding
From 
https://reference.medscape.com/drug/lidocaine-cv-lidopen-342302