Benzphetamine, commonly known as Didrex, is a sympathomimetic used to treat exogenous obesity. It has properties similar to dextroamphetamine. This drug can be used as a short-term treatment of obesity when combined with altered lifestyle factors. Benzphetamine stimulates the nervous system and suppresses the appetite through the reuptake of norepinephrine and dopamine, which prolongs their duration in the synapse so that they can bind more readily to the receptors. This drug can inhibit cocaine binding sites at the dopamine transporters. The mechanism is not fully understood, but may be similar to other dopamine reuptake inhibitors where Benzphetamine would cross the blood-brain barrier through diffusion. Dopamine is synthesized in the ventral tegmental area of the brain from tyrosine being synthesized into L-dopa by the enzyme Tyrosine 3-monooxygenase . L-Dopa is then synthesized into dopamine with the enzyme aromatic-L-amino-acid decarboxylase. Dopamine then travels to the prefrontal cortex, which is released into the synapse when the neuron is stimulated and fires. Benzphetamine binds to the sodium-dependent dopamine transporter, preventing dopamine from re-entering the presynaptic neuron. The dopamine then binds to Dopamine D4 receptors on the postsynaptic membrane. The dopamine D4 receptor activates the Gi protein cascade which inhibits adenylate cyclase. This prevents adenylate cyclase from catalyzing ATP into cAMP.

Benzphetamine Dopamine Reuptake Inhibitor Pathway References