ACTION AND MECHANISM It works by blocking sensory receptors in the mucous membranes locally. It does not penetrate deeper, so it is ineffective for inflammatory or dental pain originating in the deeper areas of the teeth and gums. Benzocaine has a very low pKa of 3.5, which makes it effective for surface anesthesia. The onset of action is 30-60 seconds, and the effect lasts for 10-15 minutes. PATIENT ADVICE PATIENT ADVICE: - Do not administer to children under 4 months of age. - Do not use for more than 7 consecutive days. - Do not apply this medication more than 4 times a day, using the lowest dose that relieves pain symptoms. - Do not chew food or gum while numbness persists due to the risk of biting your tongue or the lining of your mouth. - Oral application of benzocaine may cause swallowing problems and therefore a risk of aspiration. It is recommended not to eat for one hour after application and to avoid spraying it in the throat. - If using products containing benzocaine, be alert for signs or symptoms of methemoglobinemia such as pale, grayish, or bluish discoloration of the skin, lips, and nails, difficulty breathing, fatigue, confusion, headache, dizziness, and rapid heart rate. CONTRAINDICATIONS - Hypersensitivity to benzocaine, [ALLERGY TO ESTER-TYPE LOCAL ANESTHETICS] or to other p-aminobenzoic acid (PABA) derivatives. Cross-allergy may exist between benzocaine and other ester-type local anesthetics and with sulfonamides. - Should not be administered to children under 4 months of age. PHARMACOKINETICS Benzocaine is absorbed in very small amounts through mucous membranes. It is hydrolyzed to PABA-containing metabolites by plasma cholinesterases and, to a much lesser extent, by hepatic cholinesterases. Excretion is primarily renal, mainly as metabolites. INDICATIONS - [TEETHING]: Temporary and symptomatic relief of gum discomfort in the primary stages of teething, in children from 4 months of age. INTERACTIONS - Sulfonamides: PABA, a product of benzocaine metabolism, may inhibit the action of sulfonamides. Avoid concomitant administration. POSOLOGY Gingival use.- Children over 4 months: Place a small amount of the gel, equivalent to a grain of rice, on a clean finger or gauze and apply to the childs gum, on eruption or painful areas, up to 3-4 times a day.- Do not use for more than 7 consecutive days. PRECAUTIONS - [METHEMOGLOBINEMIA]: Cases of methemoglobinemia have been described in patients (mostly children under 4 years of age) who were administered benzocaine gel or liquid to relieve toothaches. In most cases, the product had been used incorrectly or excessively, although some cases involved appropriate use. Children under four years of age, elderly patients, and patients with certain congenital malformations such as glucose-6-phosphodiesterase deficiency, hemoglobin M disease, NADH-methemoglobin reductase (diaphorase 1) deficiency, and pyruvate kinase deficiency may also be at increased risk of developing methemoglobinemia. PRECAUTIONS RELATING TO EXCIPIENTS - This medicine contains propylene glycol, so it may cause skin irritation. ADVERSE REACTIONS - With prolonged use of benzocaine, hypersensitivity reactions (<1%) may occur, consisting of contact dermatitis. Other hypersensitivity reactions such as rashes, urticaria, edema, or anaphylaxis are extremely rare. - Prolonged contact of benzocaine with mucous membranes can cause dehydration of the epithelium and hardening of the mucous membranes. A burning sensation in the mouth has been reported. - Prolonged use has resulted in the following reported effects: [DYSGEUSIA], bad taste in the mouth, dehydration of the mucous membranes and difficulty swallowing. - In rare cases, benzocaine has been associated with methemoglobinemia, characterized by cyanosis. Most cases of methemoglobinemia in children occur due to overdose, accidental ingestion, and misuse of benzocaine preparations. COMPOSITION BENZOCAINE (DENTAL): 50 MILLIGRAMS PROPYLENE GLYCOL (EXCIPIENT): 0