LIDOCAINE HYDROCHLORIDE U.S.P. 1% _ Injection/Solution for

What is LIDOCAINE HYDROCHLORIDE U.S.P. 1% _

LIDOCAINE HYDROCHLORIDE U.S.P. 1% is a sterile, aqueous solution formulated for injection and is used primarily as a local anesthetic and sometimes as an antiarrhythmic agent. This preparation contains lidocaine hydrochloride at a concentration of 1%, meaning 10 mg of lidocaine per milliliter. The solution comes in a 50 mL plastic vial and is intended for parenteral administration under professional medical supervision.

• Generic Name: Lidocaine Hydrochloride (Lidocaine HCl)
• Concentration: 10 mg/mL (1%)
• Presentation: 50 mL sterile plastic vial
• Use: Local and regional anesthesia, intravenous antiarrhythmic (with caution)
• Onset: Rapid (usually within 2–5 minutes)
• Duration: Approximately 30–180 minutes depending on site and dosage

Lidocaine belongs to the amide class of local anesthetics and functions by blocking sodium channels in nerve membranes. This temporarily halts nerve signal transmission, leading to reversible numbness in the targeted area. It is widely employed in minor surgical procedures, dental applications, diagnostic interventions, and peripheral nerve blocks.

This 50 mL vial size is particularly useful for procedures requiring larger volumes, such as regional anesthesia, infiltration for extensive tissue repair, or intravenous regional anesthesia (Bier block), though dilution may be necessary for IVRA. The solution must be used under sterile conditions, and the vial should be discarded if contamination is suspected or if the solution appears cloudy or discolored.

It is important to use Lidocaine Hydrochloride U.S.P. 1% strictly under medical supervision. Overdosing or incorrect administration, especially intravascular injection, may result in serious central nervous system or cardiovascular complications. The availability of resuscitative equipment and trained personnel is mandatory in all settings where lidocaine is administered.

While lidocaine is generally safe when dosed appropriately, it must be used with caution in patients with liver dysfunction, heart block, or hypersensitivity to amide-type anesthetics. Combining lidocaine with epinephrine may prolong its anesthetic action and reduce systemic absorption, but this should only be done using validated, stable formulations.

How to use LIDOCAINE HYDROCHLORIDE U.S.P. 1% _

Lidocaine Hydrochloride 1% injection should be administered only by trained healthcare professionals. It is intended for local or regional anesthesia and should never be used without proper aseptic precautions and monitoring.

• Route of Administration: Local infiltration, peripheral nerve block, epidural, or intravenous regional anesthesia (IVRA)
• Preparation: Ensure the solution is clear and colorless. Check the expiry date and do not use if particulate matter or discoloration is present.
• Dose Calculation: Calculate the dosage based on the patient’s weight (mg/kg) and the procedure type. Do not exceed maximum recommended limits.
• Injection Technique: Always aspirate before injection to avoid accidental intravascular administration.
• Monitoring: Continuously monitor the patient’s vital signs and neurological status, especially during large-volume administration or nerve blocks.

For minor procedures, a few milliliters may be sufficient. For regional or nerve blocks, larger volumes up to 50 mL may be used, depending on the patient and clinical setting. Use the smallest effective dose to achieve anesthesia while minimizing systemic exposure.

This 50 mL vial is often used for extended procedures or for multiple site infiltrations. A sterile syringe should be used to withdraw the required amount, and any remaining solution must be stored correctly or discarded according to institutional policy.

Mode of Action LIDOCAINE HYDROCHLORIDE U.S.P. 1% _

Lidocaine functions as a local anesthetic by reversibly blocking the sodium ion channels in neuronal membranes. This action prevents the initiation and propagation of nerve impulses in sensory neurons, resulting in temporary loss of sensation in the targeted area.

• Target: Voltage-gated sodium channels located in peripheral nerve membranes
• Effect: Inhibition of sodium influx → Membrane stabilization → Prevention of action potential transmission
• Result: Temporary, localized anesthesia or numbness

Lidocaine’s action is both rapid and reversible. Its onset of action is usually within 2 to 5 minutes after injection, depending on the site and vascularity. Duration ranges from 30 minutes to 3 hours, which can be extended by the addition of vasoconstrictors like epinephrine.

At higher plasma concentrations, lidocaine may also have antiarrhythmic properties by depressing the automaticity of cardiac pacemaker cells and stabilizing cardiac membranes. This makes it useful in emergency settings for ventricular arrhythmias, though not its primary indication in the 1% injectable form.

It is important to note that systemic absorption, especially with large volumes or vascular areas, can lead to CNS and cardiovascular effects—thus requiring careful monitoring and dose adjustment.

LIDOCAINE HYDROCHLORIDE U.S.P. 1% _ Interactions LIDOCAINE HYDROCHLORIDE U.S.P. 1% _

Lidocaine, while generally safe when used locally and properly dosed, can interact with several medications and physiological systems, potentially leading to enhanced effects or toxicity.

• Cimetidine & Beta-Blockers: These drugs inhibit hepatic enzymes or reduce hepatic blood flow, which can slow the metabolism of lidocaine, increasing plasma levels and potential toxicity.
• Antiarrhythmic Agents (e.g., Mexiletine, Amiodarone): May have additive cardiac depressant effects, increasing the risk of bradycardia, hypotension, or arrhythmias.
• Phenytoin or Barbiturates: These may alter lidocaine metabolism, requiring dose adjustments.
• Neuromuscular Blocking Agents: Lidocaine can potentiate their effects, especially in surgical or intensive care settings.
• Alcohol & CNS Depressants: May enhance the sedative and CNS depressive effects of lidocaine if systemically absorbed.

Patients with impaired liver function, low cardiac output, or those taking multiple medications require careful dose titration. A full drug history should be obtained prior to lidocaine administration, especially when large doses are anticipated or when using lidocaine as part of a regional block or IVRA.

As with any medication, always consult drug interaction databases and clinical pharmacists before use in complex patients.

Dosage of LIDOCAINE HYDROCHLORIDE U.S.P. 1% _

The dosage of lidocaine must be carefully calculated to avoid toxic plasma levels. The standard 1% solution contains 10 mg of lidocaine per mL. Dosage varies depending on the type of procedure, the patient’s weight, age, and clinical status.

• Maximum Adult Dose (without epinephrine): 4.5 mg/kg; not to exceed 300 mg (30 mL of 1% solution)
• Maximum Adult Dose (with epinephrine): 7 mg/kg; not to exceed 500 mg (50 mL of 1% solution)
• Pediatric Dosing: Typically 1–4 mg/kg; individualize based on weight and developmental stage

Common uses and approximate volumes (based on 1% solution):

• Local infiltration: 1–5 mL
• Peripheral nerve block: 10–30 mL
• IVRA (Bier block): 30–50 mL (after dilution to 0.5%)

Always aspirate before injection to ensure you are not in a blood vessel. Lidocaine should be administered slowly, and the patient’s cardiovascular and neurological status should be monitored throughout the procedure. Use lower doses in patients with liver dysfunction, the elderly, and debilitated individuals.

Possible side effects of LIDOCAINE HYDROCHLORIDE U.S.P. 1% _

Lidocaine is typically well tolerated when used as recommended, but it may cause side effects ranging from mild local reactions to severe systemic toxicity, particularly if overdosed or accidentally administered intravascularly.

• Common Local Reactions:
  • Pain or burning at the injection site
  • Temporary numbness or tingling
  • Localized swelling or redness
• CNS Effects:
  • Dizziness, lightheadedness
  • Metallic taste, ringing in ears
  • Seizures or unconsciousness (in toxicity)
• Cardiovascular Effects:
  • Bradycardia, hypotension
  • Arrhythmias
  • In rare cases, cardiac arrest

Allergic reactions are rare with amide-type anesthetics like lidocaine but may include rash, itching, or in severe cases, anaphylaxis. Prompt medical attention is required if systemic symptoms develop.

LIDOCAINE HYDROCHLORIDE U.S.P. 1% _ Contraindications LIDOCAINE HYDROCHLORIDE U.S.P. 1% _

There are specific scenarios and patient conditions where lidocaine injection is contraindicated due to safety concerns or lack of benefit.

• Known Allergy: To lidocaine or other amide-type local anesthetics
• Severe Heart Block: Without a pacemaker, lidocaine may worsen conduction abnormalities
• Severe Hepatic Dysfunction: Impaired metabolism may lead to toxicity
• Infection at Injection Site: Increases risk of systemic infection or reduced efficacy
• Porphyria: Local anesthetics may trigger acute attacks

Use caution in patients with respiratory compromise, bradyarrhythmia, congestive heart failure, or those on medications affecting cardiac conduction. Doses should be adjusted in the elderly or debilitated patients. Ensure resuscitation equipment is immediately available when administering large doses or during regional blocks.

Storage of LIDOCAINE HYDROCHLORIDE U.S.P. 1% _

Proper storage ensures that Lidocaine Hydrochloride U.S.P. 1% remains safe and effective until used.

• Storage Temperature: 20°C to 25°C (68°F to 77°F); excursions permitted between 15–30°C
• Protect from Light: Store in a closed cabinet away from direct sunlight
• Do Not Freeze: Freezing may alter the chemical stability
• Multi-Dose Use: If the vial is accessed multiple times, it should be used within 24 hours or according to facility policy
• Inspect Before Use: Solution should be clear, colorless, and free from particulate matter

Keep out of reach of children and dispose of unused portions responsibly. Always follow institutional protocols or national regulations for the disposal of parenteral medications and sharps.