"Bath salts" are unique psychoactive drugs

Excerpts from an extensive writeup at PBS Newshour:

“Bath salts” are nothing like the epsom salts often added to bathwater; it's just the most common code name given to a specific type of synthetic drugs made in underground labs and marketed as household items. The drugs have been camouflaged as plant food, stain remover, toilet bowl cleaner and hookah cleaner. They've been sold online and in "head shops," businesses that sell drug paraphernalia. The boxes usually contain a foil wrap or plastic bag of powder, though sometimes they take the form of pills or capsules. The color of the powder ranges from white to yellow to brown, the price from $30 to $50. And nearly every box has a label that says “not for human consumption.”...

Early on, doctors began noticing something else that was strange. Compared with other drugs, bath salts didn't follow a normal dose-response pattern. With cocaine or methamphetamine, the drug entered the bloodstream, and, within hours, began to wear off. Not so for bath salts...

In the 1970s, a medicinal chemist named Richard A. Glennon was studying what it would take to convert a stimulant drug to a hallucinogen and vice versa... By introducing an oxygen atom to the side chain of amphetamine, he created something called a beta-keto amphetamine. Beta-keto amphetamine was what we now call cathinone, and at the time, in the U.S., it was a new class of stimulant...

Methamphetamine, amphetamine and cocaine all produce excessive dopamine in the space between two neurons -- the synapse -- but through different mechanisms. Both amphetamine and methamphetamine primarily work by causing an abnormal amount of dopamine to surge forth from the nerve cells, shifting the brain's reward pathways into overdrive. Cocaine on the other hand is what's called a reuptake inhibitor. That means it acts like a stopper in a kitchen sink, blocking the retreat, or reuptake, of dopamine back into the cell. It's this excessive dopamine, which goes on to stimulate the next neuron, which causes a dizzying rush of energy and a fierce, sometimes euphoric high...

Taking bath salts, it seemed, was similar to taking amphetamine and cocaine at the same time. Except for one thing: MDPV is as much as 10 times stronger than cocaine...

Authorities like Ryan have also noticed another trend -- one possibly as dangerous as the drugs themselves: they're changing. In Louisiana for example, after the five common bath salts ingredients were banned, the products didn't disappear, they just evolved. As soon as the drugs were declared illegal, drugmakers began finding new ways to get around the law by making slight tweaks to the formula, creating substances that don't show up on drug tests while skirting the law...

“There's no consistency to what's in the package,” Ryan continued. “We tested packages for how much MDPV was in them. One of them only contained 17 milligrams. One contained 2,000 milligrams.” It explained why one person might have a mild reaction to the drug, while another would end up in the psych ward or counting imaginary police cars outside their window.

Much more at the link, which also has a long comment thread.  Via BoingBoing.