Role of Levo-tetrahydropalmatine and its metabolites for management of chronic pain and opioid use disorders

•L-THP and its metabolites have dual pharmacological properties, acting as D1 agonists and D2 antagonists.•Preclinical data using various relapse models show the analgesic and anti-addiction effect of L-THP and its metabolites without altering the locomotor function.•These compounds have no addictive potential.•Available pharmacokinetic information show it is safe for clinical use without severe side effects.•Preliminary clinical studies show promising results on the effects of L-THP and its derivatives in treating drug addiction.