December 23, 2012

Safety rules for psychoactive drugs

In the early 1980s there was a significant advance in research on Parkinson’s Disease, when a number of young drug users showed up with a sudden onset of the disease.  Investigations showed that a synthetic opioid ‘legal high’ called MPPP was responsible; the methods used to synthesize it produced a byproduct MPTP that was metabolised into a potent neurotoxin and selectively absorbed into cells that thought they were getting dopamine.   Of course, this is a one-off problem with that specific drug, and not something that’s ever likely to happen again.

This sort of thing is why both animal and human safety testing is required before medications are approved, and it’s why medical chemists get rather upset at people who market untested compounds. However, it isn’t the main point behind the current NZ plans for testing legal highs, since none of the cannabis analogues Mr Dunne has banned using the interim laws would have failed basic toxicity tests. In fact, the safety problem with the cannabis analogues seems to be precisely that they are psychoactive, and that they are much easier to overdose on than real cannabis (they are ‘full agonists’, THC is a ‘partial agonist’ at the same receptors).

The problem with the new laws is that they are trying to reconcile inconsistent views of the level of safety needed.  Before Kronic started large-scale marketing and distribution, the cannabis analogues were in the sort of slightly dodgy market where you wouldn’t expect a great deal of safety testing, users knew this, and we had a pretty good compromise. When the drugs started being advertised and sold in dairies (and not just ones on K Rd), the implied level of safety was a lot higher, there were more overdose in young users, and their parents got, quite reasonably, upset.  After Mr Dunne grants his nihil obstat on production and sale, the implied safety level will even higher, and probably not achievable.

That’s why I think the animal testing issue is largely a distraction. If the regulations are going to be consistent with Mr Dunne’s bans over the past year or so, anything that has a high enough chance of approval to make the tests commercially feasible is likely to be pretty much a placebo (or placebo plus caffeine for party pills).   Whether the net health effect is positive or negative depends a lot on what is substituted for the previously-legal highs.  If it’s healthy exercise or meditation, we might come out ahead. If it’s alcohol, the impact is going to be negative.  Unfortunately, although I’m betting on a negative effect, I don’t see any easy way of getting back to the pre-Kronic situation.

 

[PS to Eric Crampton: Yes, I am indeed ignoring the benefits people get from being high. I’m pretty sure Peter Dunne is, too]

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Thomas Lumley (@tslumley) is Professor of Biostatistics at the University of Auckland. His research interests include semiparametric models, survey sampling, statistical computing, foundations of statistics, and whatever methodological problems his medical collaborators come up with. He also blogs at Biased and Inefficient See all posts by Thomas Lumley »

Comments

  • avatar

    Dunne seems to be aiming at harm minimisation. And I’m maybe more optimistic about the testing regime.

    But agreed that it’s unlikely that Dunne is counting any benefits from consumption, except inasmuch as it’s a substitution away from more dangerous things, if it is.

    11 years ago

    • avatar
      Thomas Lumley

      The optimistic view is that he’s aiming at harm minimisation. The pessimistic view is that he’s aiming at looking like he’s aiming at harm minimisation, as camouflage for a ban. I admit that his record does give some support for the optimistic view.

      But for harm minimisation you need the testing regime to actually divide more harmful from less harmful so that the less harmful and legal can compete effectively. You also want to discourage people from regarding the legal products as actually ‘safe’. So far, I don’t see it heading that way, but we’ll have to see what the actual regulations and practice turn out to be.

      I would have thought the best harm minimisation approach would be some sort of limited decriminalisation of cannabis and MDMA, which, while not actually safe, seem to be the least dangerous competitors in their respective markets. Substitutes for MDMA seem to have been especially dangerous.

      11 years ago