Dexmedetomidine, a sedative medication used by anaesthesiologists, counteracts the effects of cocaine on the human cardiovascular system, including lowering the elevated heart rate and blood pressure, according to researchers at the University of Texas Sourthwestern Medical Center.
"We have found that cocaine's effects on the cardiovascular system can be reversed by the use of a drug called dexmedetomidine, which is currently approved by the Food and Drug Administration for anaesthetic purposes in operating rooms or intensive care units," said Dr. Wanpen Vongpatanasin, associate professor of internal medicine and senior author of a study published in the Journal of the American College of Cardiology.
The researchers have found that dexmedetomidine effectively reverses the action of cocaine on heart rate, blood pressure, and vascular resistance in the skin by interfering with the ability of cocaine to increase nerve activity.
"Typically, patients with cocaine overdoses in the emergency room are treated with nitroglycerin, sedatives such as Valium, and some blood-pressure medications such as calcium channel blockers and some beta blockers," Dr. Vongpatanasin said.
"However, the standard treatments don't alleviate all of the adverse effects of cocaine on the heart, blood pressure and central nervous system" she added.
The researchers administered a small, medically approved dose of cocaine nose drops to 22 healthy adults who had never used cocaine. It doubled sympathetic nerve activity, part of the body's "automatic" response system that becomes more active during times of stress, in the participants.
Participants experienced increases in several cardiovascular parameters including heart rate, blood pressure, and resistance to blood flow in the skin.
A treatment with dexmedetomidine helped bring sypathetic nerve activity and all three cardiovascular parameters back to baseline levels, measured before the participants had been administered intranasal cocaine.
The drug proved to be more effective than intravenous saline, which was used as a placebo in another group of study participants.
"We also found that dexmedetomidine was equally effective in counteracting effects of cocaine in subjects with a rare genetic mutation thought to disrupt the effects of dexmedetomidine," said Dr. Ronald Victor, professor of internal medicine and co-author of the study.
"Because this particular mutation is more common in African-Americans than in Caucasians, our study results are applicable to a more diverse, multiethnic population," he added.
The authors of the study say that further research is needed to determine whether the treatment would be effective for acute cocaine overdose in the emergency room, and to gauge whether it would be effective in reversing cocaine-induced constriction of the coronary vessels to the same degree it does in skin vessels.