Safety Interaction Trial Ibudilast and Methamphetamine

This study is designed to collect data to determine whether a medication, ibudilast, is safe for use as a potential treatment for methamphetamine-dependent people. For 18 years in Japan and South Korea, ibudilast has been used safely in humans as a treatment for asthma, pulmonary, and cardiovascular disease. It is not known whether ibudilast is safe to use in outpatient settings with people who have methamphetamine dependence. This would be the first study to collect this information. This study is important because individuals with methamphetamine dependence often relapse to meth use, even when in treatment; some number of individuals who participate in an outpatient study will relapse to methamphetamine while taking ibudilast. It is crucial to know whether there may be interactions between ibudilast and methamphetamine before planning an outpatient clinical trial.Ibudilast is an exciting medication candidate for treating methamphetamine dependence. When individuals become abstinent from methamphetamine during early recovery, the body starts an inflammatory process in neurons, especially glial cells. Glial cells are important in that they provide support to the nerve cells that are involved in thought, movement, and other human activities. By dampening inflammation in glial cells, ibudilast may preserve glial and other nerve cells during early abstinence, which in turn may help individuals feel better and think better during treatment. The study specific aims are to determine whether ibudilast alters: 1. blood pressure and heart rate responses to methamphetamine; 2. the ratings of craving or other drug experiences from methamphetamine; 3. the reward/reinforcing effects of methamphetamine; and 4. the metabolism of methamphetamine. Over an enrollment period of 24 months, 12 methamphetamine-dependent participants who are not looking for treatment will complete this study.