The Herald this morning has more details on Jim Anderton's banning of nitrous oxide - and it looks like he's legislating by press release. Or rather, by legal opinion. Because that is what this ban is: a legal opinion from the Ministry of Health that nitrous oxide can only be dispensed with a prescription.
How strong is this? Well, nitrous oxide is listed as a prescription medicine in Schedule One of the Medicines Act 1981. But so is
Nicotine; for nasal use except when sold from a smoking cessation clinic run under the auspices of a registered medical practitioner; in medicines other than for smoking cessation
and I don't see them threatening to prosecute dairies for selling cigarettes. Why not? Because they're not being sold as medicine for a "therapeutic purpose". It's not considered prescription medicine if used for another purpose.
Unfortunately for nos users, "inducing anaesthesia" is a therapeutic purpose, which would seem to make things fairly open and shut. So yes, they can prosecute, and relying on selling food or automotive grade nitrous isn't a defence, as it is the purpose for which it is supplied, rather than its quality, which makes it illegal.
Of course, this is only a legal opinion, and there would need to be a test case on whether a "cheap headrush" is anaesthesia, but who wants to take that risk?
And on the flip side, this is yet another example of our inconsistency and hypocrisy over some drugs but not others. The vast majority of alcohol in this country is sold for exactly the same purpose as nitrous - "inducing anaesthesia" - with far worse long-term health effects and equivalent potential for dumbarse behaviour under the influence. And while nitrous has been implicated in combination with other drugs in two deaths over the past few years, alcohol verifiably kills hundreds (whether directly in accidents or indirectly through long-term side effects) every year. By any measure, it is the greater danger - but rather than banning it, we have restricted its use to adults, and changed the culture so that driving under the influence is no longer acceptable. We should adopt the same solution for nitrous.