To determine minocycline's effects on cognitive performance and measures of mood in abstinent cocaine users. Minocycline is a tetracycline derivative antibiotic that also inhibits microglia activation and the release of pro-inflammatory cytokines, chemokines, and nitric oxide (NO) production. Previous animal and human studies suggest that minocycline may have utility as a treatment for cocaine addiction.

We are proposing a randomized, double-blind, crossover study. A total of 40 male and or female subject completers will have two 4-day treatment periods, in which they will be randomized to minocycline (200 mg/day) or placebo. During the first 3 days of each treatment period, subjects will have daily clinic visits for medication administration and monitoring of adverse events. On Day 4, subjects will have an experimental session in which measures of mood and cognitive performance will be obtained. Following a washout period, ranging from 5 to 15 days, subjects will be crossed over to the alternative treatment.

This study began July 2013; currently 7 subjects were randomized with 5 completers and two drop outs. This study is in data analysis phase.

Inclusion Criteria:

• Male and females, between the ages of 21 and 50 who fulfill criteria for past cocaine dependence according to DSM-IV criteria;
• No cocaine use for the past 30 days;
• No other current dependence or abuse of other drugs of abuse or alcohol (except cocaine and tobacco);
• No current medical problems and normal ECG;
• For women, not pregnant as determined by pregnancy screening nor breast feeding, and using acceptable birth control methods.

Exclusion Criteria:

• current major psychiatric illnesses including mood, psychotic, or anxiety disorders;
• history of major medical illnesses; including liver diseases, heart disease, or other medical conditions that the physician investigator deems contraindicated for the subject to be in the study
• Current use of over-the-counter or prescription psychoactive drugs (antidepressant, anxiolytics, antipsychotics, mood stabilizers, psychostimulants) or drugs that would be expected to have major interactions with drugs to be tested, e.g., benzodiazepines, codeine, percocet, and other opiate drugs that will interact with methadone.
• Liver function tests (ALT or AST) greater than 3 times normal.
• Allergy to minocycline or other tetracyclines.