'Bath Salts' More Addictive Than Meth

Deborah Brauser

July 17, 2013

A synthetic compound found in illicit drugs known as "bath salts" may be more addictive than methamphetamine (meth), new research suggests.

A set of tests showed that after a group of rats were exposed to the chemical 3,4-methylenedioxypyrovalerone (MDPV), they went on to press a lever for a single intravenous infusion of MDPV significantly more times than they did for meth — across a wide range of doses.

When the number of times a lever needed to be pressed for an additional infusion was increased, the rats emitted an average of 60 presses for meth but an average of 600 presses for MDPV.

"If you consider these lever presses a measure of how much a rat will work to get a drug infusion, then these rats worked more than 10 times harder to get MDPV," lead author Shawn M. Aarde, PhD, research associate at the Scripps Research Institute (TSRI) in La Jolla, California, said in a release.

He added that some of the rats made 3000 lever presses for a single infusion of MDPV.

The researchers note that reports on human users of "bath salts" have suggested that effects from the drug can last a long time, even after use stops. So they hope to soon begin assessing the long-term behavioral effects of MDPV in new studies.

"MDPV looks like it's going to stick around as a recreational stimulant because it is so potent," said coinvestigator Michael A. Taffe, PhD, associate professor at TSRI, in the same release.

The study is published in the August issue of Neuropharmacology.

Direct Comparison

Dr. Taffe and coinvestigator Tobin J. Dickerson, PhD, also from TSRI, began assessing the dangerous effects of cathinone derivatives, including MDPV, several years ago.

"The drugs had not yet been scheduled, and we were able to work out how to synthesize them in sufficient quantities for animal testing," said Dr. Dickerson.

Dr. Tobin Dickerson (left) and Dr. Michael Taffe

These investigators have published 5 other studies over the past year that examined the effects of both MDPV and mephedrone.

For the current study, the investigators sought to directly compare major stimulant effects from MDPV with effects from meth in a group of 40 rats with surgically implanted intravenous catheters.

All rats were trained to press levers, initially to receive food pellets and later to receive drug infusions.

The investigators recorded the number and amount of self-infusions as well as any unusual behaviors after MDPV administration.

Greater Potency

Results showed that MDPV in self-administered doses of 0.01 to 0.50 mg/kg/infusion had "greater potency and efficacy" than meth in doses of 0.1 to 0.25 mg/kg/infusion.

Several repetitive behaviors observed in the rats after higher doses were reminiscent of human MDPV users, including tooth-grinding, compulsive skin-picking, and excessive licking.

In fact, some of the rats could not be interrupted as they repeatedly licked the clear plastic walls of the housing chambers.

"These data support a clear inference that the relatively novel stimulant drug of abuse, MDPV, poses a high risk of abuse liability" that may be greater than that of meth, write the researchers.

The investigators report that they are now setting up studies to assess the long-term behavioral effects of MDPV, as well as new members of first-generation cathinone derivatives.

"We'd like the ability to predict, for example, which ones have the highest abuse potential, which are more likely to have long-term toxicity issues, and which carry high risks of acute lethal consequences," said Dr. Taffe.

The study was funded by grants from the US Public Health Service. The study authors have disclosed no relevant financial relationships.

Neuropharmacology. 2013;71:130-140. Abstract


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