Tetracaine, also known as amethocaine, is an ester

local anesthetic A local anesthetic (LA) is a medication that causes absence of pain sensation. In the context of surgery, a local anesthetic creates an absence of pain in a specific location of the body without a loss of consciousness, as opposed to a general a ...

used to numb the eyes, nose, or throat. It may also be applied to the skin before starting an

intravenous Intravenous therapy (abbreviated as IV therapy) is a medical technique that administers fluids, medications and nutrients directly into a person's vein. The intravenous route of administration is commonly used for rehydration or to provide nutrie ...

(injection) to decrease pain from the procedure. Typically it is applied as a liquid to the area. Onset of effects when used in the eyes is within 30 seconds and last for less than 15 minutes. Common side effects include a brief period of burning at the site of use.

Allergic reactions Allergies, also known as allergic diseases, refer a number of conditions caused by the hypersensitivity of the immune system to typically harmless substances in the environment. These diseases include hay fever, food allergies, atopic derm ...

may uncommonly occur. Long-term use is generally not recommended as it may slow healing of the eye. It is unclear if use during

pregnancy Pregnancy is the time during which one or more offspring develops ( gestates) inside a woman's uterus (womb). A multiple pregnancy involves more than one offspring, such as with twins. Pregnancy usually occurs by sexual intercourse, but ...

is safe for the baby. Tetracaine is in the ester-type local anesthetic family of medications. It works by blocking the sending of

nerve impulses An action potential occurs when the membrane potential of a specific cell location rapidly rises and falls. This depolarization then causes adjacent locations to similarly depolarize. Action potentials occur in several types of animal cells, ca ...

. Tetracaine was patented in 1930 and came into medical use in 1941. It is on the World Health Organization's List of Essential Medicines

Medical uses

systematic review A systematic review is a scholarly synthesis of the evidence on a clearly presented topic using critical methods to identify, define and assess research on the topic. A systematic review extracts and interprets data from published studies on t ...

investigated tetracaine for use in emergency departments, especially for starting intravenous lines in children, in view of its analgesic and cost-saving properties. However, it did not find an improvement in first-attempt cannulations. Tetracaine is the T in TAC, a mixture of 5 to 12% tetracaine, 0.05%

adrenaline Adrenaline, also known as epinephrine, is a hormone and medication which is involved in regulating visceral functions (e.g., respiration). It appears as a white microcrystalline granule. Adrenaline is normally produced by the adrenal glands an ...

, and 4 or 10%

cocaine Cocaine (from , from , ultimately from Quechua: ''kúka'') is a central nervous system (CNS) stimulant mainly used recreationally for its euphoric effects. It is primarily obtained from the leaves of two Coca species native to South Am ...

hydrochloride used in ear, nose, and throat surgery and in the emergency department where numbing of the surface is needed rapidly, especially when children have been injured in the eye, ear, or other sensitive locations.

Mechanism

biomedical research Medical research (or biomedical research), also known as experimental medicine, encompasses a wide array of research, extending from " basic research" (also called ''bench science'' or ''bench research''), – involving fundamental scienti ...

, tetracaine is used to alter the function of calcium release channels (

ryanodine receptor Ryanodine receptors (RyR for short) form a class of intracellular calcium channels in various forms of excitable animal tissue like muscles and neurons. There are three major isoforms of the ryanodine receptor, which are found in different tissu ...

s) that control the release of calcium from intracellular stores. Tetracaine is an allosteric blocker of channel function. At low concentrations, tetracaine causes an initial inhibition of spontaneous calcium release events, while at high concentrations, tetracaine blocks release completely.

References

External links

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