Tetracaine hydrochloride, also known as amethocaine hydrochloride, is a local anesthetic used to numb the eyes, nose, or throat.It may also be used before starting an intravenous to decrease pain from the procedure.Typically it is applied as a liquid to the area.

Tetracaine hydrochloride was patented in 1930 and came into medical use in 1941.It is on the World Health Organization's List of Essential Medicines, the most effective and safe medicines needed in a health system.The wholesale cost in the developing world is about US$1.34–1.63 per 10 ml bottle.In the United Kingdom the eye drops cost the NHS about 0.49 pounds per dose.

Medical uses

A systematic review investigated Tetracaine hydrochloride 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 hydrochloride is the T in TAC, a mixture of 5 to 12% Tetracaine hydrochloride, 0.05% adrenaline, and 4 or 10% cocaine 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

In biomedical research, Tetracaine hydrochloride is used to alter the function of calcium release channels (ryanodine receptors) that control the release of calcium from intracellular stores. Tetracaine hydrochloride is an allosteric blocker of channel function. At low concentrations, Tetracaine hydrochloride causes an initial inhibition of spontaneous calcium release events, while at high concentrations, Tetracaine hydrochloride blocks release completely.

Side Effects

Get emergency medical help if signs of an allergic reaction hives; difficult breathing; swelling of your face, lips, tongue, or throat.

A light-headed feeling

Tremors, severe drowsiness

Weak or shallow breathing

Severe headache, neck stiffness, increased sensitivity to light

Numbness, tingling, burning pain, or severe shooting pains anywhere in your body.