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Medical Disclaimer: This information is for educational purposes only and is not a substitute for professional medical advice.
Brand Name
Numb 520
Generic Name
Lidocaine
Active Ingredient
LidocaineCategory
Amide Local Anesthetic [EPC]
Salt Form
Hydrochloride
Variants
4
References used for this content
This page is for informational purposes only and does not replace medical advice. Before using any prescription or over-the-counter medication for Numb 520, you must consult a qualified healthcare professional.
Detailed information about Numb 520
Lidocaine is a potent amide-type local anesthetic and Class Ib antiarrhythmic agent used to provide regional anesthesia and treat ventricular arrhythmias by stabilizing neuronal and cardiac membranes.
Dosage for Lidocaine is highly individualized based on the procedure, the area to be anesthetized, and the patient's physical status.
Lidocaine must be used with extreme caution in children. Dosing is strictly weight-based (e.g., 3 mg/kg to 5 mg/kg for local infiltration). The FDA issued a Boxed Warning against using 2% viscous lidocaine for treating teething pain in infants due to the risk of seizures and death.
While the kidneys excrete only a small amount of unchanged Lidocaine, metabolites can accumulate in patients with severe renal failure. Monitoring for toxicity is recommended.
Since Lidocaine is primarily metabolized by the liver, patients with hepatic dysfunction (e.g., cirrhosis) require significant dose reductions (often 50% or more) to avoid systemic toxicity.
Lower doses are generally recommended for geriatric patients due to age-related declines in hepatic blood flow and potential cardiac sensitivities.
If you miss an application of a topical Lidocaine patch, apply it as soon as you remember. If it is almost time for the next application, skip the missed dose. Do not apply extra patches to make up for a missed dose.
Signs of systemic Lidocaine toxicity (LAST) include perioral numbness (tingling around the mouth), metallic taste, tinnitus (ringing in the ears), tremors, seizures, and cardiac arrest. Seek emergency medical attention immediately if these symptoms occur.
> Important: Follow your healthcare provider's dosing instructions. Do not adjust your dose without medical guidance.
Common side effects are usually localized to the site of administration:
Lidocaine should only be used under the supervision of a healthcare professional or exactly as prescribed for topical use. Accidental ingestion or excessive application can lead to life-threatening systemic toxicity.
Viscous Lidocaine 2%: The FDA warns that this product is not approved for teething pain in infants. In 2014, the FDA reviewed 22 case reports of severe adverse events, including deaths, in infants and young children given viscous lidocaine for mouth pain.
Lidocaine is classified as Pregnancy Category B (historical). Animal studies have not shown harm to the fetus, and it is frequently used for epidural anesthesia during labor. However, it does cross the placenta, and large doses can cause fetal bradycardia. It should be used during pregnancy only if clearly needed.
Lidocaine is excreted into breast milk in very small amounts. The American Academy of Pediatrics considers Lidocaine to be generally compatible with breastfeeding, as the concentration is unlikely to cause adverse effects in the nursing infant.
Safety and effectiveness in pediatric patients depend on appropriate dosing. As noted, viscous lidocaine is contraindicated for teething. Pediatric patients are at a higher risk of systemic toxicity if doses are not strictly calculated by weight.
Lidocaine is a membrane-stabilizing agent. It binds to the S6 segment of domain IV of the alpha subunit of voltage-gated sodium channels. By stabilizing these channels in the inactivated state, it prevents the rapid depolarization required for nerve impulse transmission and cardiac action potential propagation.
Common questions about Numb 520
Lidocaine is primarily used as a local anesthetic to numb specific areas of the body before medical, dental, or surgical procedures. It is also available in topical forms, such as patches and creams, to treat nerve pain from shingles or minor skin irritations. In emergency medicine, healthcare providers use injectable Lidocaine to treat life-threatening heart rhythm disorders, specifically ventricular arrhythmias. It works by blocking sodium channels, which stops nerve signals and stabilizes the heart's electrical activity. Always consult your doctor to understand why Lidocaine is being used in your specific clinical situation.
The most common side effects of Lidocaine are typically localized to the area where it was applied or injected. These include redness, swelling, itching, or a pale appearance of the skin at the site of administration. Some patients may also experience temporary sensations of cold, heat, or 'pins and needles' as the numbness wears off. Systemic side effects, such as mild drowsiness or lightheadedness, can occur if the medication is absorbed into the bloodstream. If you notice any severe symptoms like confusion or difficulty breathing, contact a healthcare provider immediately.
It is generally advised to avoid alcohol while using Lidocaine, especially if it is being administered systemically or in large topical doses. Alcohol is a central nervous system depressant and can enhance the sedative effects of Lidocaine, leading to increased drowsiness or dizziness. Furthermore, alcohol can interfere with the assessment of Lidocaine's effectiveness and may mask signs of systemic toxicity. If you have received a Lidocaine injection for a procedure, wait until the effects have completely worn off before consuming alcohol. Discuss your alcohol consumption with your doctor to ensure your safety.
Lidocaine is generally considered safe for use during pregnancy when a clear medical need exists, such as for dental work or as an epidural during labor. It is classified as Pregnancy Category B, meaning animal studies have not demonstrated a risk to the fetus, though human data is limited. While it does cross the placenta, it is not known to cause birth defects when used in standard clinical doses. However, high doses can potentially affect the baby's heart rate, so it must be administered by a professional. Always inform your obstetrician if you need to receive Lidocaine while pregnant.
The onset of Lidocaine's effect depends heavily on the route of administration and the specific formulation used. When injected for local numbing, it typically begins to work within 2 to 5 minutes. Topical creams and jellies may take slightly longer, often requiring 15 to 30 minutes to achieve full effect on the skin or mucous membranes. Lidocaine patches used for chronic pain may take several days of consistent use to reach their maximum pain-relieving potential. Your healthcare provider will guide you on the expected timeframe for your specific treatment.
Yes, Lidocaine can generally be stopped suddenly without causing withdrawal symptoms, as it is not an addictive medication. However, once you stop using it, the numbing effect will wear off quickly, and any underlying pain or heart rhythm issues may return. If you are using Lidocaine patches for chronic pain, stopping them will cause the pain to reappear within a few hours. You should always follow the treatment plan prescribed by your doctor. If you experience any rebound symptoms or concerns after stopping, consult your healthcare provider for alternative management.
If you are using a topical Lidocaine patch and forget to apply it, put it on as soon as you remember. If it is almost time for your next scheduled application, skip the missed dose and return to your regular routine. Never apply two patches at once or leave a patch on for longer than 12 hours to 'make up' for a missed dose, as this increases the risk of toxicity. For injectable Lidocaine administered by a professional, missed doses are not a concern as the schedule is managed by the clinic. Contact your pharmacist if you have specific questions about your dosing schedule.
There is no clinical evidence to suggest that Lidocaine causes weight gain. Lidocaine is used for short-term anesthesia or localized pain relief and does not affect the metabolic processes or hormonal balances that typically lead to changes in body weight. If you experience sudden weight gain or swelling while using Lidocaine, it may be due to an underlying condition or a different medication you are taking. Swelling at the site of injection is a common local side effect but is not related to systemic weight gain. Consult your doctor if you have concerns about weight changes.
Lidocaine can interact with several other medications, so it is vital to provide your doctor with a full list of what you are taking. It may interact with heart medications like beta-blockers or other antiarrhythmics, which can increase the risk of side effects. Certain stomach acid reducers, like cimetidine, can slow the breakdown of Lidocaine in your liver, potentially leading to toxic levels. Additionally, using other local anesthetics simultaneously can increase the risk of systemic toxicity. Your healthcare provider will check for these interactions before administering or prescribing Lidocaine.
Yes, Lidocaine is widely available as a generic medication in almost all of its forms, including injections, topical creams, jellies, and patches. Generic versions are required by the FDA to have the same quality, strength, and purity as the brand-name products (such as Lidoderm or Xylocaine). Choosing the generic version can significantly reduce the cost of treatment for patients. Most insurance plans cover generic Lidocaine formulations. Ask your pharmacist or healthcare provider if a generic version is appropriate for your specific needs.
Other drugs with the same active ingredient (Lidocaine)
> Warning: Stop using Lidocaine and call your doctor immediately if you experience any of these:
Prolonged use of topical Lidocaine may lead to contact dermatitis (skin rash) or localized hypersensitivity. Systemic accumulation is rare with topical use but can occur if applied to broken skin or used excessively over long periods.
FDA Boxed Warning (Viscous Lidocaine 2%): This formulation should not be used to treat teething pain in infants and young children. Improper use has resulted in seizures, brain injury, and death due to accidental ingestion and rapid systemic absorption.
Report any unusual symptoms to your healthcare provider.
For patients receiving IV Lidocaine, continuous ECG (electrocardiogram) monitoring and frequent blood pressure checks are mandatory. Serum Lidocaine levels may be measured, with a therapeutic range typically between 1.5 and 5.0 mcg/mL.
Lidocaine may cause temporary dizziness or drowsiness. Do not drive or operate heavy machinery until you know how the medication affects you, especially after receiving an injection.
Alcohol may enhance the sedative effects of Lidocaine. Avoid alcohol consumption if you are using Lidocaine systemically or in large topical doses.
There is no known withdrawal syndrome for Lidocaine; however, stopping the medication will result in a rapid return of sensation or the recurrence of arrhythmias if used for that purpose.
> Important: Discuss all your medical conditions with your healthcare provider before starting Lidocaine.
There are no significant food interactions for topical or injectable Lidocaine. However, if using viscous Lidocaine for the throat, food should be avoided for one hour post-application to prevent aspiration (inhaling food into the lungs).
Lidocaine may interfere with certain diagnostic tests, such as the bentiromide test for pancreatic function. Always inform your lab technician if you have recently received Lidocaine.
> Important: Tell your doctor about ALL medications, supplements, and herbal products you are taking.
There is no cross-sensitivity between amide-type anesthetics (like Lidocaine) and ester-type anesthetics (like Procaine or Benzocaine). If a patient is allergic to one class, the other may often be used safely, though skin testing is recommended.
> Important: Your healthcare provider will evaluate your complete medical history before prescribing Lidocaine.
Elderly patients are more likely to have reduced hepatic function and decreased cardiac output. Lower doses and careful monitoring for CNS and cardiac toxicity are essential in this population.
No specific dose adjustment is usually required for a single dose, but for continuous infusions, monitoring for metabolite accumulation is necessary to prevent neurotoxicity.
Patients with significant hepatic impairment (Child-Pugh Class B or C) require a 50% reduction in maintenance infusion doses for antiarrhythmic therapy to avoid toxic accumulation.
> Important: Special populations require individualized medical assessment.
| Parameter | Value |
|---|---|
| Bioavailability | 35% (Oral - due to first pass); 100% (IV) |
| Protein Binding | 60% - 80% (mainly to AAG) |
| Half-life | 1.5 - 2 hours (Adults) |
| Tmax | 30 - 45 minutes (Topical) |
| Metabolism | Hepatic (CYP1A2, CYP3A4) |
| Excretion | Renal (<10% unchanged) |
Lidocaine is the prototypical Amide Local Anesthetic. It is also a Class Ib Antiarrhythmic according to the Vaughan Williams classification system.