What it's for (Indications)
- Lignocaine with adrenaline is indicated for producing local or regional anesthesia for a wide array of surgical, dental, and diagnostic procedures where prolonged anesthesia and reduced local bleeding are desired.
- Its primary applications include infiltration anesthesia for minor surgical procedures, suturing of lacerations, and dermatological excisions, providing targeted numbing of a specific area.
- Furthermore, it is extensively utilized for various peripheral nerve blocks, such as dental blocks (e.
- g.
- , inferior alveolar nerve block, posterior superior alveolar nerve block) to achieve profound anesthesia for extensive dental work, and digital nerve blocks for procedures on fingers or toes.
- It is also employed for other regional anesthetic techniques where the vasoconstrictive properties of adrenaline are beneficial in extending the duration of the anesthetic effect and minimizing systemic absorption of lignocaine, thereby enhancing the safety profile and therapeutic window.
- This combination is particularly advantageous in surgical fields prone to bleeding, as adrenaline's vasoconstrictive action aids in hemostasis, improving visibility for the surgeon and potentially reducing blood loss during the procedure.
- The specific concentration and volume used depend on the site of administration, the type of procedure, and the patient's individual characteristics.
Dosage Information
| Type | Guideline |
|---|---|
| Standard | The dosage of lignocaine with adrenaline must be carefully individualized, taking into account the specific anesthetic procedure, the area to be anesthetized, the vascularity of the tissues, the duration of the planned procedure, and the patient's physical status, age, and weight. It is imperative to use the lowest effective concentration and volume to achieve the desired anesthetic effect. For infiltration anesthesia, doses typically range from 20 mg to 200 mg of lignocaine, depending on the area and extent of the procedure. For nerve blocks, such as dental blocks, a common dose might be 30 mg to 60 mg of lignocaine (e.g., 1-2 carpules of 2% lignocaine with adrenaline 1:100,000). The maximum recommended dose for lignocaine with adrenaline in healthy adults is generally up to 7 mg/kg (or 0.175 mL/kg of 2% solution) not exceeding a total of 500 mg of lignocaine in a single session, though this can vary based on specific guidelines and patient factors. It is crucial to administer the solution slowly, with frequent aspiration to prevent inadvertent intravascular injection, which can lead to systemic toxicity. Pediatric dosages must be calculated precisely based on body weight, typically not exceeding 5 mg/kg of lignocaine. Close monitoring for adverse reactions and cardiovascular parameters is essential throughout and after administration. |
Safety & Warnings
Common Side Effects
- Side effects associated with lignocaine with adrenaline can be categorized based on their systemic or local impact, and often relate to dose and inadvertent intravascular administration.
- Common, less severe local reactions include pain, burning, or stinging at the injection site, localized edema, and bruising.
- Systemic effects of lignocaine are primarily neurological, manifesting as central nervous system (CNS) excitation followed by depression.
- Initial symptoms may include lightheadedness, dizziness, tinnitus, circumoral numbness, taste disturbances, drowsiness, tremors, disorientation, and slurred speech.
- As toxicity progresses, patients may experience muscle twitching, convulsions, respiratory depression, and ultimately coma.
- Cardiovascular effects of lignocaine, particularly with high systemic concentrations, can include bradycardia, hypotension, and in severe cases, cardiac arrest.
- The adrenaline component can cause cardiovascular effects such as palpitations, tachycardia, hypertension, and arrhythmias due to its vasoconstrictive and stimulatory properties, especially if absorbed systemically.
- Adrenergic effects may also include anxiety, restlessness, and headache.
- Allergic reactions, though rare, can range from skin rashes and urticaria to severe anaphylaxis.
- It is imperative to recognize these potential adverse effects promptly to initiate appropriate management.
Serious Warnings
- Black Box Warning: None
- Lignocaine with adrenaline carries several important warnings and precautions to ensure patient safety.
- It is absolutely contraindicated in patients with a known hypersensitivity or allergic reaction to amide-type local anesthetics or adrenaline.
- It should never be used for intravenous regional anesthesia (Bier block) due to the risk of gangrene if the tourniquet fails, nor should it be injected directly into blood vessels.
- Extreme caution is warranted in patients with pre-existing cardiovascular conditions, including severe hypertension, ischemic heart disease, cardiac arrhythmias, and congestive heart failure, as adrenaline can exacerbate these conditions.
- Patients with uncontrolled hyperthyroidism, pheochromocytoma, or narrow-angle glaucoma should also be treated with great care due to adrenaline's sympathomimetic effects.
- Diabetics require close monitoring as adrenaline can transiently increase blood glucose levels.
- The combination should be used cautiously in areas with compromised blood supply or in tissues supplied by end-arteries (e.
- g.
- , fingers, toes, earlobes, nose, penis) where vasoconstriction from adrenaline could lead to ischemia or necrosis.
- Patients with impaired hepatic or renal function may have reduced metabolism or excretion of lignocaine, increasing the risk of systemic toxicity.
- Careful aspiration prior to injection is crucial to avoid inadvertent intravascular administration.
- Drug interactions with beta-blockers, tricyclic antidepressants, MAO inhibitors, and phenothiazines can potentiate the effects of adrenaline, leading to severe hypertensive episodes or arrhythmias.
- Pregnancy and lactation require careful risk-benefit assessment, as both lignocaine and adrenaline can cross the placental barrier.
How it Works (Mechanism of Action)
The mechanism of action of lignocaine with adrenaline involves the synergistic effects of two distinct pharmacological agents: lignocaine, a local anesthetic, and adrenaline (epinephrine), a vasoconstrictor. Lignocaine, an amide-type local anesthetic, primarily functions by reversibly blocking voltage-gated sodium channels in the neuronal cell membranes. This blockade prevents the influx of sodium ions, which is essential for the depolarization phase of the action potential. By stabilizing the resting membrane potential and inhibiting the generation and conduction of nerve impulses, lignocaine effectively prevents the transmission of pain signals from the site of injection to the central nervous system, thereby producing local anesthesia. Adrenaline, an alpha- and beta-adrenergic agonist, exerts a localized vasoconstrictive effect on the arterioles at the site of injection. This vasoconstriction serves multiple critical purposes: it significantly reduces local blood flow, which in turn slows the rate at which lignocaine is absorbed from the injection site into the systemic circulation. This delayed systemic absorption has several benefits, including prolonging the duration of the anesthetic effect by keeping a higher concentration of lignocaine at the nerve fibers, reducing the peak plasma concentration of lignocaine and thereby minimizing the risk of systemic toxicity, and providing hemostasis by constricting local blood vessels, which reduces bleeding in the surgical field and improves visibility.