first phase's half-life (distribution) is 3 to 6hours, and the following phase's half-life (elimination) is 4.1 to 14.6hours. The elimination half-life of extended-release trazodone is 9.1 to 13.2hours. The elimination half-life of mCPP is 2.6 to 16.0hours and is longer than that of trazodone. Metabolites are conjugated to gluconic acid or glutathione and around 70 to 75% of 14C-labelled trazodone was found to be excreted in the urine within 72hours. The remaining drug and its metabolites are excreted in the faeces via biliary elimination. Less than 1% of the drug is excreted in its unchanged form. After an oral dose of trazodone, it was found to be excreted 20% in the urine as TPA and conjugates, 9% as the dihydrodiol metabolite, and less than 1% as unconjugated mCPP. mCPP is glucuronidated and sulfated similarly to other trazodone metabolites. Chemistry Trazodone is a triazolopyridine derivative and a phenylpiperazine that is structurally related to nefazodone and etoperidone, each of which are derivatives of it. Flibanserin is an analogue of trazodone. History Trazodone was developed in Italy, in the 1960s, by Angelini Research Laboratories as a second-generation antidepressant. It was developed according to the mental pain hypothesis, which was postulated from studying patients and which proposes that major depression is associated with a decreased pain threshold. In sharp contrast to most other antidepressants available at the time of its development, trazodone showed minimal effects on muscarinic cholinergic receptors. Trazodone was patented and marketed in many countries all over the world. It was approved by the Food and Drug Administration (FDA) in 1981 and was the first non-tricyclic or MAOI antidepressant approved in the US. Society and culture Generic names Trazodone is the generic name of the drug and its , , and , while trazodone hydrochloride is its , , , and . Brand names Trazodone has been marketed under a large number of brand names throughout the world. Major brand names include Desyrel (worldwide), Donaren (Brazil), Molipaxin (Ireland, United Kingdom), Oleptro (United States), Trazorel (Canada), and Trittico (worldwide). Research Trazodone may be effective in the treatment of sexual dysfunction, for instance female sexual dysfunction and erectile dysfunction. A 2003 systematic review and meta-analysis found some indication that trazodone may be useful in the treatment of erectile dysfunction. Besides trazodone alone, a combination of trazodone and bupropion (developmental code names and tentative brand names S1P-104, S1P-205, Lorexys, and Orexa) is under development for