LIDOCAINE HYDROCHLORIDE

Lidocaine Viscous 2% (Lidocaine Hydrochloride Oral Topical Solution USP) contains a local anesthetic agent and is administered topically. Lidocaine Viscous 2% (Lidocaine Hydrochloride Oral Topical Solution USP) contains lidocaine hydrochloride, which is chemically designated as acetamide, 2-(diethylamino)-N-(2,6-dimethylphenyl)-,monohydrochloride, and has the following structural formula: The molecular formula of lidocaine is C 14 H 22 N 2 O. The molecular weight is 234.34. Composition of Solution : Each mL contains 20 mg (2%) of lidocaine hydrochloride USP and the following inactive ingredients: carboxymethylcellulose sodium, flavoring, methylparaben, propylparaben, purified water and saccharin sodium. chem-structure.jpg

Lidocaine is indicated for the production of topical anesthesia of irritated or inflamed mucous membranes of the mouth and pharynx. It is also useful for reducing gagging during the taking of X-ray pictures and dental impressions.

Adult The maximum recommended single dose of lidocaine for healthy adults should be such that the dose of lidocaine does not exceed 4.5 mg/kg or 2 mg/lb body weight and does not in any case exceed a total of 300 mg. For symptomatic treatment of irritated or inflamed mucous membranes of the mouth and pharynx, the usual adult dose is 15 mL undiluted. For use in the mouth, the solution should be swished around in the mouth and spit out. For use in the pharynx, the undiluted solution should be gargled and may be swallowed. This dose should not be administered at intervals of less than three hours, and not more than eight doses should be given in a 24-hour period. The dosage should be adjusted commensurate with the patient’s age, weight and physical condition (see PRECAUTIONS ). Pediatric Care must be taken to ensure correct dosage in all pediatric patients as there have been cases of overdose due to inappropriate dosing. It is difficult to recommend a maximum dose of any drug for children since this varies as a function of age and weight. For children over 3 years of age who have a normal lean body mass and normal body development, the maximum dose is determined by the child’s weight or age. For example: in a child of 5 years weighing 50 lbs., the dose of lidocaine should not exceed 75 to 100 mg (3.7 to 5 mL of lidocaine). For infants and in children under 3 years of age, the solution should be accurately measured and no more than 1.2 mL be applied to the immediate area with a cotton-tipped applicator. Wait at least 3 hours before giving the next dose; a maximum of four doses may be given in a 12-hour period. Lidocaine should only be used if the underlying condition requires treatment with a volume of product that is less than or equal to 1.2 mL.

Lidocaine is contraindicated in patients with a known history of hypersensitivity to local anesthetics of the amide type, or to other components of the solution.

Adverse experiences following the administration of lidocaine are similar in nature to those observed with other amide local anesthetic agents. These adverse experiences are, in general, dose-related and may result from high plasma levels caused by excessive dosage or rapid absorption, or may result from a hypersensitivity, idiosyncrasy or diminished tolerance on the part of the patient. Serious adverse experiences are generally systemic in nature. The following types are those most commonly reported: Central Nervous System CNS manifestations are excitatory and/or depressant and may be characterized by lightheadedness, 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. The excitatory manifestations may be very brief or may not occur at all, in which case the first manifestation of toxicity may be drowsiness merging into unconsciousness and respiratory arrest. Drowsiness following the administration of lidocaine is usually an early sign of a high blood level of the drug and may occur as a consequence of rapid absorption. Cardiovascular System Cardiovascular manifestations are usually depressant and are characterized by bradycardia, hypotension, and cardiovascular collapse, which may lead to cardiac arrest. Allergic Allergic reactions are characterized by cutaneous lesions, urticaria, edema or anaphylactoid reactions. Allergic reactions may occur as a result of sensitivity either to the local anesthetic agent or to the methylparaben and/or propylparaben used in this formulation. Allergic reactions as a result of sensitivity to lidocaine are extremely rare and, if they occur, should be managed by conventional means. The detection of sensitivity by skin testing is of doubtful value.

Patients who are administered local anesthetics are at increased risk of developing methemoglobinemia when concurrently exposed to the following drugs, which could include other local anesthetics: Examples of Drugs Associated with Methemoglobinemia: Class Examples Nitrates/Nitrites nitroglycerin, nitroprusside, nitric oxide, nitrous oxide Local anesthetics benzocaine, lidocaine, bupivacaine, mepivacaine, tetracaine, prilocaine, procaine, articaine, ropivacaine Antineoplastic agents cyclophosphamide, flutamide, rasburicase, ifosfamide, hydroxyurea Antibiotics dapsone, sulfonamides, nitrofurantoin, para-aminosalicylic acid Antimalarials chloroquine, primaquine Anticonvulsants phenytoin, sodium valproate, phenobarbital Other drugs acetaminophen, metoclopramide, sulfasalazine, quinine