<unk>  is generally well tolerated and non-toxic when applied topically as recommended. However, there have been reports of serious, life-threatening adverse effects (e.g., seizures, coma, irregular heart beat, respiratory depression) with over-application of topical products or when applying topical products that contain high concentrations of<unk>  to the skin. Overapplication of oral anesthetics such as<unk>  can increase the risk of pulmonary aspiration by relaxing the gag-reflex and allowing regurgitated stomach contents or oral secretions to enter the airway. Applying an oral anesthetic and consuming beverages before going to bed can be particularly hazardous. The topical use of higher concentration (10–20%)<unk>  products applied to the mouth or mucous membranes has been found to be a cause of methemoglobinemia, a disorder in which the amount of oxygen carried by the blood is greatly reduced. This side effect is most common in children under two years of age. As a result, the FDA has stated that<unk>  products should not be used in children under two years of age, unless directed by and supervised by a healthcare professional. In European countries, the contraindication applies to children under 12 years of age. Symptoms of methemoglobinemia usually occur within minutes to hours of applying<unk> , and can occur upon the first-time use or after additional use.<unk>  may cause allergic reactions. These include: * Contact dermatitis (redness and itchiness) * Anaphylaxis (rare)
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