Lidothol Gel

Lidothol Gel is indicated for relief of pain associated with arthritis, backache, cramps, discomfort, neckache, soreness, sprains, strains. It should be applied only to intact skin.

Apply Lidothol Gel to intact skin to cover the most painful area. Clean and dry the affected area. Apply product directly to your skin, up to 4 times daily. Clothing may be worn over the area of application. If irritation or a burning sensation occurs during application, wash the product off your skin and do not reapply until the irritation subsides. When Lidothol Gel is used concomitantly with other products containing local anesthetic agents, the amount absorbed from all formulations must be considered.

Medicines intended to be applied to the skin should not be swallowed. Lidothol Gel is flammable. Keep away from open flame. You should never heat, microwave, or add the medicine to hot water. Risk of Methemoglobinemia Cases of methemoglobinemia have been reported in association with lidocaine use. Although all patients are at risk for methemoglobinemia, patients with glucose-6-phosphate dehydrogenase deficiency, congenital or idiopathic methemoglobinemia, cardiac or pulmonary compromise, infants under 6 months of age, and concurrent exposure to oxidizing agents or their metabolites are more susceptible to developing the condition. If lidocaine must be used in these patients, close monitoring for symptoms and signs of methemoglobinemia is recommended. Signs of methemoglobinemia may occur immediately or may be delayed some hours after exposure, and are characterized by a cyanotic skin discoloration and/or abnormal coloration of the blood. Methemoglobin levels may continue to rise; therefore, immediate treatment is required to avert more serious central nervous system and cardiovascular adverse effects, including seizures, coma, arrhythmias, and death. Excessive Dosing Excessive dosing by applying Lidothol Gel to larger areas could result in increased absorption of lidocaine and high blood concentrations, leading to serious adverse effects (see ADVERSE REACTIONS, Systemic Reactions). Lidocaine toxicity could be expected at lidocaine blood concentrations above 5 mcg/mL. The blood concentration of lidocaine is determined by the rate of systemic absorption and elimination. Longer duration of application of more than the recommended number of doses, smaller patients, or impaired elimination may all contribute to increased blood concentration of lidocaine.

Lidothol Gel is contraindicated in patients with a known history of sensitivity to local anesthetics of the amide type, or to any other component of the product.

Application Site Reactions During or immediately after treatment with Lidothol Gel, the skin at the site of application may develop blisters, bruising, burning sensation, depigmentation, dermatitis, discoloration, edema, erythema, exfoliation, irritation, papules, petechia, pruritus, vesicles, or may be the locus of abnormal sensation. These reactions are generally mild and transient, resolving spontaneously within a few minutes to hours. Other Adverse Events Due to the nature and limitation of spontaneous reports in post marketing surveillance, causality has not been established for additional reported adverse events including: Asthenia, confusion, disorientation, dizziness, headache, hyperesthesia, hypoesthesia, lightheadedness, metallic taste, nausea, nervousness, pain exacerbated, paresthesia, somnolence, taste alteration, vomiting, visual disturbances such as blurred vision, flushing, tinnitus, and tremor. Systemic (Dose-Related) Reactions Systemic adverse reactions following appropriate use of Lidothol Gel are unlikely, due to the small dose absorbed (see CLINICAL PHARMACOLOGY, Pharmacokinetics). Systemic adverse effects of lidocaine is similar in nature to those observed with other amide local anesthetic agents, including CNS excitation and/or depression (light headedness, nervousness, apprehension, euphoria, confusion, dizziness, drowsiness, tinnitus, blurred or double vision, vomiting, sensations of heat, cold or numbness, twitching, tremors, convulsions, unconsciousness, respiratory depression and arrest). Excitatory CNS reactions may be brief or not occur at all, in which case the first manifestation may be drowsiness merging into unconsciousness. Cardiovascular manifestations may include bradycardia, hypotension and cardiovascular collapse leading to arrest. Sensitivity reactions associated with the use of mentholated products have been reported. Use of mentholated nasal drops in infants has evidently caused isolated cases of spasm of the larynx, and a few cases of nervous or digestive system disturbance have been associated with excessive inhalation or oral exposure to menthol

Pharmacodynamics Lidocaine is an amide-type local anesthetic agent. The penetration of lidocaine into intact skin after application of Lidothol Gel is sufficient to produce annalgesic effect, but less than the amount necessary to produce a complete sensory block. Menthol is a covalent organic compound made synthetically or obtained from peppermint or other mint oils. Menthol induces a cooling sensation on the skin upon topical application by stimulating the cold-sensitive receptors expressed on the skin, without actually causing a drop in the skin temperature. Pharmacokinetics Absorption The amount of lidocaine systemically absorbed from Lidothol Gel is directly related to both the duration of application and the surface area over which it is applied. Menthol occurs in numerous over-the-counter products. Although extensively used, there have been no estimates of human exposure following administration via dermal application. Distribution At concentrations produced by application of Lidothol Gel, approximately 70% of the lidocaine dose is reported to be bound to plasma proteins, primarily alpha-1-acid glycoprotein. At higher plasma concentrations (1 to 4 mcg/mL of free base), the plasma protein binding of lidocaine is concentration dependent. Metabolism It is not known if Lidothol Gel is metabolized in the skin. Excretion Lidocaine and its metabolites are excreted by the kidneys. Less than 10% of lidocaine is excreted unchanged. The half-life of lidocaine elimination from the plasma following IV administration is 81 to 149 minutes (mean 107 ± 22 SD, n = 15). The systemic clearance is 0.33 to 0.90 L/min (mean 0.64 ± 2 max max 0.18 SD, n = 15).