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CAS number 84-22-0 N
PubChem 5419
ChemSpider 5226 YesY
UNII S9U025Y077 YesY
KEGG D08578 YesY
ChEBI CHEBI:28674 YesY
ATC code R01AA06,S01GA02
Jmol-3D images Image 1
Molecular formula C13H16N2
Molar mass 200.28 g/mol
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
 N (verify) (what is: YesY/N?)
Infobox references

Tetrahydrozoline (INN: Tetryzoline), a derivative of imidazoline, is found in over-the-counter eye drops and nasal sprays. Other derivatives include naphazoline, oxymetazoline, and xylometazoline.

Tetrahydrozoline is an alpha agonist and its main mechanism of action is the constriction of conjunctival blood vessels.[1] This serves to relieve the redness of the eye caused by minor ocular irritants.

An urban legend suggests that tetrahydrozoline can cause violent diarrhea if administered orally, such as by putting a few drops of Visine in an unsuspecting person's beverage. However, the actual results of the "Visine Prank" may be worse, varying from severe nausea and vomiting to seizures or a coma. Diarrhea is not a side effect.[2]


Tetrahydrozoline can be synthesized in one step by the heterocyclization of 1-cyanotetralin with ethylenediamine.[3]

Tetrahydrozoline synthesis.png

See also[edit]


  1. ^ Dahlström M, Lindgren F, Berntsson K et al. (July 2005). "Evidence for different pharmacological targets for imidazoline compounds inhibiting settlement of the barnacle Balanus improvisus". J. Exp. Zoolog. Part a Comp. Exp. Biol. 303 (7): 551–62. doi:10.1002/jez.a.163. PMID 15945078. 
  2. ^ "Visine Prank: Mickey Red Eyes". Snopes. 29 June 2009. Retrieved 28 July 2010. 
  3. ^ M. E. Synerholm, L. H. Jules, M. Sahyun, U.S. Patent 2,731,471 (1956)