Norepinephrine releasing agent

A norepinephrine releasing agent (NRA), also known as an adrenergic releasing agent, is a catecholaminergic type of drug that induces the release of norepinephrine (noradrenaline) and epinephrine (adrenaline) from the pre-synaptic neuron into the synapse. This in turn leads to increased extracellular concentrations of norepinephrine and epinephrine therefore an increase in adrenergic neurotransmission.^[1]^[2]

A closely related type of drug is a norepinephrine reuptake inhibitor (NRI). Another class of drugs that stimulates adrenergic activity is the adrenergic receptor agonist class.

Uses and examples

NRAs are used for a variety of clinical indications including the following:

For the treatment of attention deficit hyperactivity disorder (ADHD) — e.g., amphetamine, dextroamphetamine, levoamphetamine, methamphetamine
As anorectics in the treatment of obesity — e.g., amphetamine, phentermine, benzphetamine, phenmetrazine, aminorex
As wakefulness-promoting agents in the treatment of narcolepsy — e.g., amphetamine, methamphetamine
As nasal decongestants — e.g., levomethamphetamine, propylhexedrine, ephedrine, pseudoephedrine, phenylpropanolamine

They are also used as recreational drugs, though this is typically reserved only for those that also induce the release of serotonin and/or dopamine like amphetamine, methamphetamine, MDMA, mephedrone, and 4-methylaminorex, among others.^[3]

Cathine and cathinone are NRAs found naturally in Catha edulis. Ephedrine and pseudoephedrine are also found naturally in Ephedra sinica. Both of these plants are used medicinally (and recreationally as well regarding the former). The endogenous trace amines phenethylamine and tyramine are NRAs found in many animals, including humans.

Selective NRAs include ephedrine, pseudoephedrine, phenylpropanolamine, levoamphetamine, levomethamphetamine, and phentermine. These drugs also release dopamine to a much lesser extent however. NRAs play a significant role in treating ADHD, obesity, narcolepsy, and as nasal decongestants by enhancing adrenergic neurotransmission.