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Methylamphetamine — street names include crystal meth, tweak and
ice — is now a Class A Controlled Drug, which means that it is
considered to be one of the most harmful drugs of abuse. At the beginning
of last week it was a Class B CD.
Reclassification
was recommended by the Advisory Council on the Misuse
of Drugs because of fears that an epidemic of abuse in the Far East,
the US and parts of Europe could spread to the UK.
The recommendation reversed the ACMD’s 2005 advice to leave methylamphetamine
in Class B because there was, at that time, little evidence of significant
misuse in the UK and fears that reclassification could draw attention
to the drug. But, in mid-2006 the ACMD decided that the abuse of methylamphetamine
was becoming more widespread in the UK — although it remains rare — and
the police had discovered a number of illicit laboratories synthesising
it. This, coupled with increased media attention to the drug, made the
advisory council reconsider.
Simple synthesis
The ACMD has also now pointed out that methylamphetamine is simple
to synthesise in domestic kitchens from pseudoephedrine and ephedrine.
It recommended that steps be taken to limit their availability.
Such steps have already been taken in countries where methylamphetamine
abuse is an established problem, including the US, Australia and New
Zealand.
In the US last year, federal legislation moved ephedrine and pseudoephedrine
from the over-the-counter category to a new behind-the-counter category,
meaning that products cannot be available by self-selection, that purchasers
have to prove their identity and that records of sales have to be kept
for at least two years. Some individual states introduced legislation
that made them available only on prescription. Down under
In Australia, pseudoephedrine-containing products were made subject
to tighter controls last year as well. Some products became prescription-only;
others had to be sold personally by pharmacists. Things went further
in New Zealand, where ephedrine and pseudoephedrine became Controlled
Drugs, but with exemptions to allow sales to continue under certain
circumstances and under pharmaceutical supervision.
In both Australia and New Zealand much of the supply of illicit methylamphetamine
was being synthesised using pseudoephedrine and ephedrine extracted from
stolen or illicitly imported medicines.
These facts raise the question of whether medicines that contain pseudoephedrine
or ephedrine should be more tightly controlled in the UK. Currently,
both ingredients are classified as prescription-only medicines, but with
exemptions that allow products containing limited doses to be available
as P medicines.
Sheila Kelly, executive director of the Proprietary Association of Great
Britain, is clear that there is no justification for changing this. “There
is not that much of a problem with crystal meth in the UK at the moment,” she
said. “And pseudoephedrine is one of the most important P ingredients.”
In the US, only 10 per cent of illicit methylamphetamine is produced
from OTC medicines. And most of this involves medicines stolen from factories
or from pharmacies by ram-raiders, Mrs Kelly says. Although she accepts
that some is obtained from pharmacies by people going from shop to shop
buying medicines. The rest is manufactured on an industrial scale — mainly
in Mexico.
But Mrs Kelly is adamant that there is no evidence that OTC medicines
are being used to make methylamphetamine in Europe.
“The police have never found OTC products in places where they have
found crystal meth,” she said. “People who are making it are
getting the raw material. We’re a long way from people going from
shop to shop.”
So what would happen if pseudoephedrine, in particular, was no longer
available as an active ingredient for OTC use?
The immediate impact would be that the public would no longer have easy
access to remedies to relieve the symptoms of the common cold.
“Only 3 per cent of people go to the doctor for a cold because effective
products are available,” Mrs Kelly said. Disruption of cold treatments
Reformulation would also mean lengthy delays to the introduction of
replacement products — it could take as long as two years for them to be
fully tested, validated and authorised by the Medicines and Healthcare
products Regulatory Agency, according to Mrs Kelly.
Ron Eccles, of Cardiff University’s Common Cold Centre, said: “Pseudo-ephedrine
has been shown to be effective in clinical trials. One can argue about
the level of decongestion achieved with an oral product and whether it
is clinically effective, but there are objective changes in congestion
and people do feel better.”
Conversely, Professor Eccles says that no clinical trials in the public
domain support the efficacy of phenylephrine, which is the main alternative
ingredient. “Phenylephrine is a poor substitute for pseudoephedrine
as an orally administered decongestant as it is extensively metabolised
in the gut and its efficacy as a decongestant is unproven.”
Nevertheless, reformulation is seen as the way forward by the advisory
council. ACMD member Kay Roberts said: “In the UK, I’m not
sure we would miss pseudoephedrine,
although phenylephrine is probably not as
effective.”
She explained that the ACMD’s recommendation that the availability
of pseudoephedrine be restricted was based on evidence of the environmental
damage illicit conversion can do (see Panel below).
“My inclination is to err on the side of caution,” she said. “We
did look at it very carefully and this is not a knee-jerk reaction.”
The Society p114
Why the worry about methylamphetamine?
Methylamphetamine is chemically closely related
to amphetamine, but has more intense central pharmacological
effects than amphetamine
and less pronounced peripheral effects. It can be taken by smoking — unlike
amphetamine, which breaks down before it vaporises — and
produces much more long-lasting effects than amphetamine (it has
a longer half-life) or inhaled “crack cocaine”.
Methylamphetamine readily crosses the blood-brain barrier leading
to euphoria and excitement through the release of noradrenaline
(norepinephrine) and dopamine. Users who smoke it risk developing “meth
mouth” characterised by broken, discoloured and rotting teeth
as a result of suppressed salivary secretion.
It is readily synthesised from pseudoephedrine and ephedrine by
reduction with red phosphorus and iodine, although people who do
this illicitly put themselves and property at considerable risk
because it involves the use of volatile solvents and the production
of toxic waste. |
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The
Pharmaceutical Journal