Tetryzoline

Tetryzoline, also known as tetrahydrozoline, is a derivative of imidazoline with central and peripheral alpha (α)-adrenergic properties. Available since the 1950s, tetryzoline is a selective α-receptor agonist that is used as an ocular and nasal decongestant. Tetryzoline is found in a wide array of over-the-counter eye drops, including the most common brand, Visine. Tetryzoline is also found in combination products with other lubricants and anti-irritants, such as povidone, polyethylene glycol 400, dextran, and zinc sulfate. It is also used in combination with other drug classes, such as antihistamines, corticosteroids, and glucocorticoids in other countries. Tetryzoline is also found in nasal spray under the trade name Tyzine, which is used for decongestion of nasal and nasopharyngeal mucosa.

As it causes profound sedation in children and adults, tetryzoline is increasingly becoming scrutinized for possible drug overdose and toxicity from accidental ingestion. It has also been misused for non-therapeutic purposes as a causative drug for several cases of drug-facilitated sexual assault.