Lofexidine is an alpha2-adrenergic receptor agonist, historically used as a short-acting anti-hypertensive, but more commonly used to alleviate physical symptoms of heroin and opiate withdrawal.

In the United Kingdom, the hydrochloride form, lofexidine HCl, has been licensed and sold since 1992 for opiate withdrawal relief in tablet form as BritLofex by Britannia Pharmaceuticals. BritLofex is only available by prescription. Lofexidine is also commonly used in conjunction with the opioid receptor antagonist naltrexone in rapid detoxification cases. When these two drugs are paired, naltrexone is administered to induce an opioid-receptor blockade sending the subject into immediate withdrawal and accelerating the detoxification process, while lofexidine is given to relieve the symptoms associated with the withdrawal including chills, sweating, stomach cramps, muscle pain, and runny nose. As the withdrawal symptoms subside, lofexidine works to restore natural levels of norepinephrine and endorphins to pre-opiate addiction levels