Suppression of withdrawal symptoms by dynorphin in heroin addicts.

The effectiveness of dynorphin-(1-13) in suppressing heroin withdrawal was studied. At a dose of 60 micrograms/kg body weight, dynorphin-(1-13) was effective in suppressing withdrawal symptoms. When saline was administered a strong placebo effect was noticed that, however, did not influence the outcome of the results. Only three out of the twelve patients receiving dynorphin-(1-13) experienced some mild side-effects such as feeling warm, dizziness and precordial formication.