Tricaine mesylate (Tricaine methanesulfonate, TMS, MS-222, Syncaine, Tricaine-S,), is white powder used for

anesthesia Anesthesia is a state of controlled, temporary loss of sensation or awareness that is induced for medical or veterinary purposes. It may include some or all of analgesia (relief from or prevention of pain), paralysis (muscle relaxation), ...

, sedation, or

euthanasia Euthanasia (from el, εὐθανασία 'good death': εὖ, ''eu'' 'well, good' + θάνατος, ''thanatos'' 'death') is the practice of intentionally ending life to eliminate pain and suffering. Different countries have different eut ...

of fish. TMS is the only anesthetic licensed in the United States for fin fish that are intended for human consumption. The drug can have selective toxicity for poikilotherms due to their lower rate of metabolism in the liver. Tricaine is an anaesthetic that operates by preventing sodium ions to enter the cell and thus silencing action potentials. This has the net effect of blocking signal exchange between the

brain A brain is an organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. It is located in the head, usually close to the sensory organs for senses such as vision. It is the most complex organ in a v ...

and extremities. MSD Animal Health is one of the largest manufacturers of Tricaine in Norway and other European markets under the brand name Finquel. The largest manufacturer of Tricaine in North America is Syndel under the brand name Syncaine. Syncaine is manufactured in

Ferndale, Washington Ferndale is a city in Whatcom County, Washington, United States. The population was 11,415 at the 2010 census. It is the third largest city in Whatcom County and located near the Lummi Nation. History First settled in 1872, Ferndale was given ...

, in the United States. Syncaine is used for handling fish,

amphibian Amphibians are tetrapod, four-limbed and ectothermic vertebrates of the Class (biology), class Amphibia. All living amphibians belong to the group Lissamphibia. They inhabit a wide variety of habitats, with most species living within terres ...

s, and other cold-blooded animals during manual spawning, as well as during marking, measuring, photography, research, surgical operations, transport, and weighing of fish. The optimum concentration may vary with the size and species of the fish, and other variables. It is easily soluble in water (both fresh and salt) but it drastically decreases the pH of water, increasing the acidity, which may be toxic for fish.

Sodium bicarbonate Sodium bicarbonate (IUPAC name: sodium hydrogencarbonate), commonly known as baking soda or bicarbonate of soda, is a chemical compound with the formula NaHCO3. It is a salt composed of a sodium cation ( Na+) and a bicarbonate anion ( HCO3−) ...

can be used to buffer the solution to a pH range of 6.5-7.5. Usually an equal amount of buffer is added to attain a neutral pH. In salt/marine/sea water, the buffer use may not be necessary because sea water itself has buffering capacity . The solution of TMS needs to be prepared freshly each time because TMS is light-sensitive and might form toxic by-products upon exposure to light . Fish treated with Tricaine cannot be slaughtered for human consumption until a certain withdrawal period is reached, for example 21 days in the United States for Syncaine.

References

{{Reflist General anesthetics Benzoate esters