Lofexidine is newly FDA approved in the United States under the brand name LUCEMYRA for the treatment of opioid withdrawal symptoms in adults. Lofexidine acts as an agonist to α2 adrenergic receptors. These receptors inhibit adenylyl cyclase activity, leading to the inhibition of the second messenger, cyclic adenosine monophosphate (cAMP). The inhibition of cAMP leads to potassium efflux through calcium-activated channels, blocking calcium ions from entering the nerve terminal, resulting in suppression of neural firing, inhibition of norepinephrine release. Lofexidine replaces the opioid-driven inhibition of cAMP production and moderating the symptoms of opioid withdrawal.

Dexlofexidine is an isomer “+“ of lofexidine, which is agonist of alpha 2-adrenoceptor, but in 10 times less potent than the other isomer, levlofexidine.

Levlofexidine is R-enantiomer of a α2A adrenergic receptor agonist Lofexidine. Levlofexidine (as a component of Lofexidine) can be used as a short-acting anti-hypertensive but is mostly used to help relieve symptoms of heroin or opiate withdrawal in opiate dependency. Lofexidine is approved in the United Kingdom but is still undergoing clinical trials in the United States. Levlofexidine showed an approximately 9-fold higher affinity than Dexlofexidine for the alpha 2-adrenoceptor-like binding sites in rat brain membranes identified by [3H]-clonidine and was 4 times more potent at displacing [3H]-prazosin from alpha 1-adrenoceptors. The possibility of using lofexidine to treat alcohol addiction withdrawal symptoms has been investigated and has not yet been shown to be an effective treatment.