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A topical anesthetic is a local anesthetic that is used to numb the surface of a body part. They can be used to numb any area of the skin as well as the front of the eyeball, the inside of the nose, ear or throat, the anus and the genital area.〔(Healthopedia.com )〕 Topical anesthetics are available in creams, ointments, aerosols, sprays, lotions, and jellies. Examples include benzocaine, butamben, dibucaine, lidocaine, oxybuprocaine, pramoxine, proparacaine, proxymetacaine, and tetracaine (also named amethocaine) all derived from the natural chemical cocaine from the coca plant which is still used for some medical procedures such as rhinoplasties. == Usage == Topical anesthetics are used to relieve pain and itching caused by conditions such as sunburn or other minor burns, insect bites or stings, poison ivy, poison oak, poison sumac, and minor cuts and scratches.〔(DrLinhart.com )〕 Topical anesthetics are used in ophthalmology and optometry to numb the surface of the eye (the outermost layers of the cornea and conjunctiva) to: * Perform a contact/applanation tonometry. * Perform a Schirmer's test (The Schirmer's test is sometimes used with a topical eye anesthetic, sometimes without. The use of a topical anesthetic might impede the reliability of the Schirmer's test and should be avoided if possible.). * Remove small foreign objects from the uppermost layer of the cornea or conjunctiva. The deeper and the larger a foreign object which should be removed lies within the cornea and the more complicated it is to remove it, the more drops of topical anesthetic are necessary prior to the removal of the foreign object to numb the surface of the eye with enough intensity and duration. In dentistry, topical anesthetics are used to numb oral tissue before administering a dental local anesthetic due to the entry of the needle into the soft tissues of the oral cavity. 〔''Local Anesthesia for the Dental Hygienist,'' Logothetis, Elsevier, 2012〕 Some topical anesthetics (e.g. oxybuprocaine) are also used in otolaryngology. Topical anesthetics are now commonly used in the temporary relief of premature ejaculation when applied to the glans (head) of the penis. Benzocaine or lidocaine are typically used for this purpose as they are available OTC (lidocaine is more powerful than benzocaine). 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「topical anesthetic」の詳細全文を読む スポンサード リンク
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