DOX as a Potential Treatment for Methamphetamine Dependence

The purpose of the study is to asses the potential interactions between methamphetamine and doxazosin in methamphetamine-dependent volunteers who are not seeking treatment. The study will evaluate the effects of doxazosin on the cardiovascular and subjective effects of methamphetamine in a human laboratory study. The primary objective is to determine the safety of treatment with doxazosin in methamphetamine-dependent volunteers by examining hemodynamic and subjective effects of administration of ascending doses of methamphetamine and a placebo dose during treatment with doxazosin. The secondary objective is to determine effects of treatment with doxazosin, as compared to placebo, on subjective effects produced by administration of methamphetamine or placebo