Clinical data
Trade namesBontril
  • C (US)
Routes of
ATC code
  • none
Legal status
Legal status
Pharmacokinetic data
BioavailabilityPeak plasma levels occur within 1 to 3 hours. Absorption is usually complete by 4 to 6 hours
Elimination half-life19-24 hours
ExcretionUrinary elimination
  • 3,4-dimethyl-2-phenylmorpholine
CAS Number
PubChem CID
CompTox Dashboard (EPA)
ECHA InfoCard100.010.186 Edit this at Wikidata
Chemical and physical data
Molar mass191.274 g·mol−1
3D model (JSmol)
  • O2C(c1ccccc1)C(N(C)CC2)C
  • InChI=1S/C12H17NO/c1-10-12(14-9-8-13(10)2)11-6-4-3-5-7-11/h3-7,10,12H,8-9H2,1-2H3 checkY

Phendimetrazine (Bontril, Adipost, Anorex-SR, Appecon, Melfiat, Obezine, Phendiet, Plegine, Prelu-2, Statobex) is a stimulant drug of the morpholine chemical class used as an appetite suppressant.[2]


Phendimetrazine functions as a prodrug to phenmetrazine; approximately 30 percent of an oral dose is converted into it. Phendimetrazine can essentially be thought of as an extended-release formulation of phenmetrazine with less potential for abuse. Phendimetrazine is an anorectic drug which acts as a norepinephrine-dopamine releasing agent (NDRA).[3]

As an amphetamine congener, its structure incorporates the backbone of methamphetamine, a potent CNS stimulant. While the addition of an N-methyl group to amphetamine significantly increases its potency and bioavailability, methylation of phenmetrazine renders the compound virtually inactive. However, phendimetrazine is a prodrug for phenmetrazine which acts as the active metabolite. Phendimetrazine possesses preferable pharmacokinetics over phenmetrazine as a therapeutic agent because its metabolization by demethylases produces a more steady and prolonged exposure of active drug within the body. This decreases abuse potential as the peak blood-concentration of active phenmetrazine that's produced from a single dose of phendimetrazine is lower than a single therapeutically equivalent dose of phenmetrazine.

Indicated as a short-term secondary treatment for exogenous obesity, phendimetrazine immediate-release 35mg tablets are typically consumed one hour before meals, not to exceed three doses daily. Phendimetrazine is also manufactured as a 105mg extended-release capsule for once daily dosing, typically consumed 30 to 60 minutes before a morning meal. Whereas the immediate-release formulation has a maximum daily dosage of 210mg (6 tablets), the extended-release capsules have a maximum daily dosage of 105mg (one capsule).


According to the List of Psychotropic Substances under International Control published by the International Narcotics Control Board, phendimetrazine is a Schedule III controlled substance under the Convention on Psychotropic Substances.[4]

See also


  1. ^ Anvisa (2023-03-31). "RDC Nº 784 - Listas de Substâncias Entorpecentes, Psicotrópicas, Precursoras e Outras sob Controle Especial" [Collegiate Board Resolution No. 784 - Lists of Narcotic, Psychotropic, Precursor, and Other Substances under Special Control] (in Brazilian Portuguese). Diário Oficial da União (published 2023-04-04). Archived from the original on 2023-08-03. Retrieved 2023-08-16.
  2. ^ Landau D, Jackson J, Gonzalez G (2008). "A case of demand ischemia from phendimetrazine". Cases J. 1 (1): 105. doi:10.1186/1757-1626-1-105. PMC 2531092. PMID 18710555.
  3. ^ Rothman RB, Baumann MH (2006). "Therapeutic potential of monoamine transporter substrates". Current Topics in Medicinal Chemistry. 6 (17): 1845–59. doi:10.2174/156802606778249766. PMID 17017961. Archived from the original on 2017-03-26. Retrieved 2020-05-05.
  4. ^ "List of psychotropic substances under international control" (PDF). Archived from the original (PDF) on 2012-08-31. Retrieved 2005-06-15.