Drug Groups

illicit; approved

Description

A sympathomimetic drug used primarily as an appetite depressant. Its actions and mechanisms are similar to dextroamphetamine. [PubChem]

Indication

Used as an anorectic in the treatment of obesity.

Pharmacology

Phenmetrazine is a sympathomimetic drug used primarily as an appetite depressant. Its actions and mechanisms are similar to dextroamphetamine. Amphetamines are non-catecholamine sympathomimetic amines with CNS stimulant activity. Phenmetrazine was originally sold under the tradename Preludin as an anorectic. It has since been removed from the market. It is by some considered to have a greater potential for addiction than the amphetamines, and has been abused in many countries, for example Sweden.

Toxicity

Adult monkeys have an LD₅₀ of 15 to 20 mg/kg, whereas for young monkeys the LD₅₀ is only 5 mg/kg. Symptoms of overdose include acute central nervous system stimulation, cardiotoxicity causing tachycardia, arrhythmias, hypertension, and cardiovascular collapse. Whilst some patients show signs of toxicity at blood concentrations of 20 µg/L, chronic abusers of amphetamine have been known to have blood concentration of up to 3000 µg/L.

Affected Organisms

Biotransformation

Primarily hepatic (via CYP3A and CYP2D6). Resistant to metabolism by monoamine oxidase. Metabolism involves deamination to para-hydroxyamphetamine and phenylacetone; this latter compound is subsequently oxidize to benzoic acid and excreted as glucuronide or glycine (hippuric acid) conjugate. Smaller amounts of amphetamine are converted to norephedrine by oxidation.

Absorption

Readily absorbed from the gastro-intestinal tract and buccal mucosa.

Half Life

16 to 31 hours

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