RTI-336 is an interesting example of a phenyltropane that is being explored in the context of a treatment for cocaine addiction. RTI-336 is a DRI and thus specifically targets the DAT which is responsible for the addictive properties of cocaine. Although there may be a role for NET inhibition and acetylcholinergic actions, clearly it is DA which is the critical neurotransmitter. Dopamine is a biological precursor to noradrenaline. DA is made from tyrosine, which is a non-essential amino acid given that it can be made from phenylalanine.