A diuretic commonly used to treat hypertension and congestive heart failure may improve brain blood flow in cocaine addicts, according to a study by Yale researchers in the June issue of the journal Drug and Alcohol Dependence.
Chronic cocaine use is associated with decreases in blood flow to the brain, but the mechanism for this decrease is not fully understood. Researchers theorize cocaine-induced constriction of the arteries in the brain and/or increased blood clotting may be involved.
The problems associated with decreased brain blood flow in some cocaine abusers are like the results of major strokes such as paralysis, loss of ability to speak, severe cognitive impairment and, in the worst cases, death, said Thomas Kosten, M.D., professor of psychiatry at Yale School of Medicine and lead author of the study.
"The patients in these studies with reduced blood flow to the brain had significant impairment in thinking, concentrating, reading and remembering things," Kosten said. "They also had significant depressive symptoms that may have been related to these deficiencies in brain functioning due to a lack of sufficient blood flow to the neurons."
He said increasing blood flow back to normal can reverse these cognitive impairments and make these patients more responsive to behavioral treatments, which require learning of new skills to refuse drugs. "These improvements in cognition can also enable these patients to return to productive employment and be active members of society," Kosten said.
To gauge the effects of the diuretic amiloride on cocaine dependent subjects, Kosten and his colleagues administered amiloride, aspirin or placebo to 49 patients for one month while they resided on a research unit. Blood flow in the brain was measured on admission to the unit and at the end of treatment.
At the time they were enrolled in the study, cocaine-dependent subjects showed decreased cerebral blood flow compared to 18 control subjects. After four weeks of treatment, the researchers found that the amiloride, but not aspirin or placebo, improved blood flow in the brain. None of the treatments affected blood clotting.
The authors speculate that the improvement by amiloride may be due to the medication's ability to dilate the arteries in the brain. The authors also pointed out that amiloride may be used in combination with other medications that also increase cerebral blood flow to treat cocaine dependent patients.
Co-authors included Christopher Gottschalk, M.D., Karen Tucker, Christine Rinder, M.D., Holly Dey, M.D., and Henry Rinder, M.D.