Chlorphentermine, sold under the brand names Apsedon, Desopimon, and Lucofen, is a serotonergic appetite suppressant of the amphetamine family.

It is no longer used due mainly to safety concerns, as it has a serotonergic effects profile similar to other withdrawn appetite suppressants such as fenfluramine and aminorex which were found to cause pulmonary hypertension and cardiac fibrosis following prolonged use.

[27][26] The activity of chlorphentermine as an SSRA is in contrast to phentermine, which acts as a selective norepinephrine and dopamine releasing agent (NDRA).

[29] In addition, unlike para-chloroamphetamine (PCA), chlorphentermine does not produce the head-twitch response, a behavioral proxy of psychedelic effects, in animals.

[29] In contrast to fenfluramine and norfenfluramine, chlorphentermine shows negligible activity as an agonist of the serotonin 5-HT2A, 5-HT2B, and 5-HT2C receptors.

[26] Despite its lack of direct agonism at the serotonin 5-HT2B receptors, chlorphentermine shows induction of primary pulmonary hypertension in animal models.

[31] In contrast to PCA, preliminary animal experiments suggest that chlorphentermine is non-neurotoxic, although more research in this area is still needed.

[23] Chlorphentermine is also closely structurally related to certain other phentermines including cericlamine, cloforex, clortermine, etolorex, and methylenedioxyphentermine (MDPH).