4 Clinical Trials for Various Conditions
More people worldwide use amphetamine-type stimulants than any illicit drug besides cannabis, and methamphetamine (MA) abuse and dependence is the fastest growing drug problem in the United States. Much work remains in identifying an effective pharmacotherapy for MA dependence. The neurobiological actions produced by MA involve dopamine (DA), serotonin, and norepinephrine, but also include alterations to cholinergic neurotransmitter systems. Candidate compounds that target acetylcholine (ACh) are attractive options for development that have not received adequate attention. Varenicline is a drug that increases the release of DA in the brain and it is logical to assume that it would to some extent compensate for the reduction in these neurotransmitters that occurs in MA withdrawal. Current research has linked certain genes that are related to neurotransmitters with drug abuse and memory impairment (e.g., A1 allele for the D2 dopamine receptor and catechol-O-methyltransferase). We will take blood samples and test for these genes in order to relate the findings to brain function. This is a double-blind, placebo-controlled, within-subjects study to determine the safety and tolerability of MA in MA-dependent volunteers treated with varenicline and placebo.
Methamphetamine (MA) abuse is the fastest growing drug problem in the United States and is responsible for significant public health complications, including HIV infection. As a result effective treatments for MA dependence are urgently needed. There are currently no efficacious medications for MA dependence, although results from preliminary randomized trials of bupropion for MA dependence found bupropion to be more effective than placebo, but only among subgroups of participants, including those with lower frequency of MA use at baseline. A growing body of preclinical and clinical studies suggest that cholinergic mechanisms play an important role in the neurobiology of MA and other stimulant dependence, such as nicotine dependence. Mechanistically, cholinergic medications may alleviate MA-associated cognitive dysfunction, thereby improving outcomes of treatment for MA dependence. Varenicline is a partial agonist at α4β2 nicotinic receptors and a full agonist at α7 nicotinic receptors that has been approved as an anti-cigarette smoking medication. In order to assess the potential efficacy of varenicline for methamphetamine dependence, we will perform a clinical trial to assess if varenicline compared to placebo results in greater: 1. reductions in methamphetamine use; 2. treatment retention;
Modafinil is a non-amphetamine type stimulant that acts as a wakefulness-promoting drug, and is approved for managing symptoms of narcolepsy (i.e., daytime somnolence). Its precise mechanism of action in promoting wakefulness remains unclear. This trial is a placebo-controlled double-blind trial of modafinil, on a platform of contingency management (CM) and individual cognitive-behavioral (CBT) counseling, for the treatment of methamphetamine dependence. Participants in this study will complete a 2-week baseline screening period during which they will provide urine samples and complete physical and psychological assessments to establish their eligibility for the study. In addition, participants will be asked to provide a blood or saliva specimen for genetic testing in order to identify genetic variations that influence response to methamphetamine and to treatment with modafinil. Upon successful completion of screening, participants will be randomly assigned to receive either modafinil (400mg qd) or placebo during the 12 weeks of the study. Neither the participants nor study staff will know who is receiving active medication or placebo. Regardless of medication condition, all participants will receive CM and weekly individual CBT counseling sessions to help them stop using methamphetamine and prevent relapse. They will attend the clinical research site (either at the UCLA Hollywood Clinic, or the Rancho Cucamonga site) three times per week, providing urine samples at each visit, completing data measures, and receiving individual CBT counseling on one visit each week. At the end of the 12-week study, the medication or placebo will be discontinued. Participants will return to the research site approximately 30 days following medication discontinuation for a brief health check to assess any possible lingering side effects and complete brief data measures.
Currently there are no medications approved for the treatment of methamphetamine addiction. Bupropion is an antidepressant that is approved by the Food and Drug Administration (FDA) for the treatment of depression and for cigarette smoking cessation but is not approved by the FDA for the treatment of methamphetamine addiction. Preliminary research studies suggest that bupropion may help people receiving treatment for methamphetamine addiction to reduce or to stop their methamphetamine use. But results of these studies also suggest that bupropion may help certain groups of patients more than others, such as men versus women and light versus heavy methamphetamine users, although the reasons for this difference are not known. One possibility is that a person's genetic make up may influence whether or not they respond to treatment with bupropion for methamphetamine addiction. The purpose of the study is to determine if bupropion is can help people reduce or stop their methamphetamine use and to investigate whether genetic variations influence whether people respond to treatment with bupropion for methamphetamine addiction, which may help doctors and patients better decide if treatment with bupropion will be beneficial or not. To identify possible genetic variations that influence response to bupropion, we will perform genetic tests on blood or saliva specimens from participants receiving treatment with either bupropion or placebo (which is a pill that contains no medication) in conjunction with standard cognitive behavioral therapy drug counseling. We will compare methamphetamine use, as assessed with urine drug screens, among participants receiving bupropion versus those receiving placebo to determine if bupropion helps people to reduce or stop their methamphetamine use. We will then compare the results of the genetic tests among participants who respond and who do not respond to bupropion. In addition, since the amount of methamphetamine a person uses was associated with response to bupropion in preliminary studies, we will also compare the results of genetic testing among persons with heavy versus light methamphetamine use before entering treatment. Results of this study have the potential to provide insights into the biology of methamphetamine addiction and help increase the understanding of how bupropion works. This information could be useful to develop effective medications for methamphetamine addiction and to improve the ability of clinicians to provide treatment to patients with methamphetamine addiction.