Tetracaine

Description for Tetracaine

Tetracaine is a local anesthetic or numbing medicine that is used to numb the throat, eyes, or nose. Normally, the drug is administered before starting a surgery to decrease pain from the procedure. Tetracaine is applied to the eyes 30 minutes before the start of an intravenous and its effects can last up to 15 minutes.

Tetracaine was developed to address the low potency andshort duration of action of procaine and chloroprocaine. The addition of the butyl side chain on the para nitrogen increasesthe lipid solubility of the drug and enhances the topical potencyof tetracaine. The plasma half-life is 120 to 150 seconds.Topically applied tetracaine to unbroken skin requires 30 to 45minutes to confer topical anesthesia. Tetracaine 4% gel is superiorthan eutectic mixture with lidocaine (EMLA) (an emulsionof lidocaine and prilocaine) in preventing pain associatedwith needle procedures in children. Tetracaine metabolism issimilar to procaine ester metabolism yielding parabutylaminobenzoicacid and dimethylaminoethanol and conjugatesexcreted in the urine. The pKa of the dimethylated nitrogen is8.4 and tetracaine is formulated as a hydrochloride salt with apH of 3.5 to 6.0. The increased absorption from topical siteshas resulted in reported toxicity. Overdoses of tetracaine mayproduce central nervous system (CNS) toxicity and seizure activitywith fatalities from circulatory depression reported.No selective cardiac toxicity is seen with tetracaine althoughhypotension has been reported. Tetracaine is employed for infiltrationanesthesia, spinal anesthesia, or topical use.

Uses

Tetracaine is more irritating than proparacaine but is sometimes used in veterinary medicine. It is indicated to produce local anesthesia of short duration for ophthalmic procedures including measurement of intraocular pressure (tonometry), removal of foreign bodies and sutures, and conjunctival and corneal scraping in diagnosis and gonioscopy. Tetracaine is also indicated to produce local anesthesia prior to surgical procedures in humans such as cataract extraction and pterygium excision, usually as an adjunct to locally injected anesthetics. Ophthalmic solutions used for intraocular procedures should be preservative-free. Preservatives may cause damage to the corneal epithelium if a significant quantity of solution enters the eye through the incision.

RELATED PRODUCTS:

Lidocaine                         CAS  137-58-6

Benzocaine                      CAS 94-09-7

Tetracaine                        CAS 94-24-6

Procaine                           CAS 59-46-1

Lidocaine hydrochloride   CAS 73-78-9

Tetracaine hydrochloride  CAS 136-47-0