Phendimetrazine, sold under the brand name Bontril among others, is a stimulant medication of the morpholine chemical class used as an appetite suppressant.

Pharmacology

Phendimetrazine functions as a prodrug of 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). 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).

Legality

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.

Synthesis

The reaction between N-methylethanolamine and 2-bromopropiophenone gives compound (3), which is reductively cyclized using formic acid to synthesize phendimetrazine.

Society and culture

Brand names

It is sold under various brand names including Bontril, Bontril PDM, Adipost, Anorex-SR, Appecon, Melfiat, Obezine, Phendiet, Plegine, Prelu-2, and Statobex.