Download From prescription-only to over-the

Published Online May 3, 2009
From prescription-only to over-the-counter
medicines (‘PoM to P’): time for an
intermediate category
Jeffrey K. Aronson*
Department of Primary Health Care, University of Oxford, Rosemary Rue Building, Old Road
Campus, Headington, Oxford OX3 7LF, UK
Background: Increasing numbers of medicines are being made available over
the counter in the UK, by purchase in a pharmacy or from other less wellregulated outlets. When this is allowed by the Licensing Authority, it is often
subject to certain restrictions. However, some drugs that could usefully be
converted from prescription-only medicines (PoM status) to over-the-counter
sales in a pharmacy (P status) are not suitable for full over-the-counter status,
even with restrictions; and in some cases restrictions vitiate the usefulness of
the medicine.
Areas of agreement: Drugs that can acceptably be switched from PoM status to
P status include those that are used in the treatment of minor ailments or
injuries, for health promotion or in palliative care.
Areas of controversy: However, not all drugs that are being switched fall into
these categories. Ready availability of antimicrobial drugs over the counter, one
of which (azithromycin) has recently been switched, could encourage the
emergence of resistant organisms. Drugs that are used for long-term treatment
and lifestyle drugs are also controversial, particularly if their adverse effects
are of potential concern. On the other hand, the availability of many drugs via
the internet removes the ability of regulators to control the supply of such
drugs.
Accepted: April 8, 2009
*Correspondence to:
J. K. Aronson,
Department of Primary
Health Care,
University of Oxford,
Rosemary Rue Building,
Old Road Campus,
Headington, Oxford OX3
7LF, UK.
E-mail: jeffrey.aronson@
clinpharm.ox.ac.uk
A possible solution: A new category of purchase, Pharmacist Consultation and
Supply, with built-in safeguards, could improve the availability of some
medicines under more careful control than is currently available for overthe-counter medicines.
Keywords: prescription-only medicines/pharmacy-only medicines/over-thecounter medicines/sildenafil/Viagra/simvastatin
British Medical Bulletin 2009; 90: 63–69
DOI:10.1093/bmb/ldp015
& The Author 2009. Published by Oxford University Press. All rights reserved.
For permissions, please e-mail: [email protected]
J. K. Aronson
There are three legitimate ways of obtaining licensed medicines in the
UK, defined in the 1968 Medicines Act.
†
PoM: prescription-only medicines from qualified prescribers (doctors,
dentists, nurse or pharmacist independent prescribers, or supplementary
prescribers).
†
P: pharmacy-only medicines, obtained without a prescription (colloquially,
‘over the counter’) from, or under the supervision of, a qualified
pharmacist.
†
GSL: general sales list medicines, obtained without a prescription from,
for example, a pharmacy or a supermarket.
P and GSL medicines can also be prescribed in the usual way.
Most medicines are restricted to prescription-only status, but in
recent years, in political response to a perceived public demand for
readier access to medicines,1 increasing numbers of medicines have
been reclassified (or ‘switched’) ‘from PoM to P’. Examples have
included omeprazole and simvastatin, both of which were switched in
2004,2,3 and emergency contraception with levonorgestrel, which
became available over the counter in 2001.4 Switches from P to GSL
have also occurred.
Before reclassification from PoM to P can occur, the Licensing
Authority must be satisfied that it would be safe for the medicine to be
supplied without a prescription.5 A medicine may not be switched if it
meets any of the following criteria, laid down in section 58A of the
Medicines Act for a prescription-only medicine:
†
it is likely to present a direct or indirect danger to human health, even
when used correctly, if used without the supervision of a doctor; or
†
is frequently and to a very wide extent used incorrectly, and as a result is
likely to present a direct or indirect danger to human health; or
†
contains substances or preparations of substances of which the activity
requires, or the adverse effects require, further investigation; or
†
is normally prescribed by a doctor for parenteral administration.
However, there are positive criteria for switching,6 criteria that are
either necessary or desirable.3 The necessary criteria are that:
†
the patient either should be able to make the diagnosis or should know
what the diagnosis is, based on an authoritative opinion;
†
the treatment should be efficacious;
†
the benefit-to-harm balance should be favourable.
Additional, pragmatic reasons for switching are to make a medicine
more readily and quickly available and to shift the cost from the public
purse to the private.3
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From ‘PoM’ to ‘P’: time for an intermediate category
Most P-category medicines are used in the treatment of minor ailments or injuries, for health promotion, or in palliative care, although
the list is beginning to include medicines that are used for acute and
chronic conditions that do not fall into these categories and may also
be extended to ‘lifestyle drugs’, such as sildenafil for erectile dysfunction and orlistat for obesity. Black triangle drugs (recently licensed
medicines whose adverse effects have not been extensively described)
would not normally be considered as candidates for reclassification. In
the face of new evidence, a P medicine can have its P status revoked,7
as happened to terfenadine and astemizole,8,9 when it was discovered
that they could prolong the QT interval, with a risk of torsade
de pointes, an effect that was enhanced by inhibition of their
metabolism by grapefruit juice.10
Even when a medicine is considered suitable for over-the-counter
sales, those who advise the Licensing Authority may be reluctant to
suggest granting P status, because of concerns about misuse, adverse
drug effects and adverse drug –drug interactions. When they do advise
that a switch be granted, they will often recommend certain restrictions.7 For example, both omeprazole and simvastatin (usual doses of
20 –40 mg/day) are supplied over the counter as tablets containing
10 mg. Omeprazole can be sold direct to adults over 18 years of age,
only for the short-term relief of reflux-like symptoms, with a
maximum daily dose of 20 mg, for a maximum of 4 weeks, in a pack
of no more than 28 tablets; comparable restrictions apply to simvastatin. However, there is an important difference between these two
drugs: as an over-the-counter drug omeprazole is used for short-term
relief, whereas simvastatin is indicated for long-term prevention.
Emergency contraception represents a third category—one-off administration; in that case restrictions are not applied—for the over-thecounter formulation both the indication and the dose are exactly the
same as for the prescription formulation, and the two are identical in
all respects (except for brand name and price).11
Switching sildenafil
In this issue of the British Medical Bulletin, Rubin and Wylie12 ask
whether sildenafil (Viagraw) should be reclassified from PoM to
P. They conclude that it should. Their arguments are sound, although
they only tangentially allude to the fact that sildenafil can already
easily be obtained ‘over the counter’, via the internet ( just Google ‘buy
Viagra’), by anyone who wants it for recreational purposes,13 without
any guarantee of quality, efficacy or safety, the three cornerstones of
medicines regulation. In 2003 Viagra was fourth of the top 10 medicines
British Medical Bulletin 2009;90
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J. K. Aronson
bought over the internet, the others being Xenical (orlistat for weight
loss), Proscar (finasteride for benign prostatic hyperplasia), Propecia
(finasteride for androgenetic alopecia in men), Uprima (sublingual apomorphine for erectile dysfunction), Reductil (sibutramine for appetite
suppression), Zyban (bupropion for smoking cessation), Relenza (zanamivir for influenza), phentermine (for appetite suppression) and Meridia
(sibutramine for appetite suppression).14 This provides an argument for
making it more readily available in reliable formulations.
Other problematic medicines
But the current legislation poses a difficulty. The process of switching
from PoM to P was made easier in 2002, and the P category is now
overburdened by the different varieties of treatment that it includes.
One-off or short-term treatments do not necessarily pose problems.
A single tablet of levonorgestrel can be purchased for emergency contraception without the need for medical scrutiny, and the likelihood of
an adverse effect is very small; limited supplies of sildenafil for erectile
impotence could be comparable. Omeprazole and ranitidine, both
available over the counter for the short-term relief of symptoms of
heartburn, are similarly non-problematic, although one would hope
that a pharmacist would advise any patient who buys them regularly to
seek medical advice.
However, the management of chronic problems is more difficult.
Take, for example, irritable bowel syndrome, for which hyoscine butylbromide is licensed for over-the-counter purchase. The dosage is the
same as the prescription dosage, but supply is limited to 3 days’ worth
at full dosage (although patients can buy the drug over the internet).
Furthermore, patients are advised not to use the drug unless their
doctor has made the diagnosis of irritable bowel syndrome.15 Why
should such a medicine, for what is a chronic condition, be made available over the counter in this way? Presumably the manufacturer finds it
profitable. This may be because many doctors doubt its efficacy
(despite some evidence16) and are likely to refuse to prescribe hyoscine
butylbromide, while many patients, less than satisfied by the limited
options their doctor offers them, will buy it over the counter and may
gain relief. However, it may not be wise to allow a patient to keep on
self-medicating, with a risk of missing a more serious diagnosis.17
A possible solution
There is a case here for an intermediate category between PoM and P;
let us call it PCS (Pharmacist Consultation and Supply). For medicines
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From ‘PoM’ to ‘P’: time for an intermediate category
in such a category, after diagnosis (usually by a doctor) the patient
would buy a reasonable supply from a pharmacist, who would monitor
their use of it and either repeat the order if they considered it appropriate or refer the patient back to the doctor. Some doctors will dislike
the idea that a pharmacist might be given this kind of responsibility,
but pharmacists already counsel patients, and the extra responsibility
of dispensing a PCS product could encourage higher standards of
pharmacy practice in initiating and monitoring therapy with selected
medicines. Furthermore, safeguards could be introduced. For example,
a pharmacist who supplies a PCS drug could be required to inform the
patient’s doctor; linked electronic records, if they become available,
would add extra security, allowing the information to be transmitted
automatically to the general practitioner (GP) and other pharmacists,
thus controlling the extent of supply and facilitating research into outcomes. A PCS scheme would be comparable to the ‘pharmacist-only’
scheme in Australia18 and the ‘restricted medicines’ scheme in New
Zealand.19
Recently, azithromycin has been accorded P status for treating
infections with Chlamydia, the first oral antimicrobial drug to be so
classified. There are serious concerns about the emergence of resistance
organisms through overuse of antimicrobial drugs and there are reservations about this move.20 Pharmacists are being required to undertake
a diagnostic test through a central laboratory before selling azithromycin,21 and this may be a sufficient safeguard. However, a PCS
scheme would have been ideal for this drug and indication.
Now consider how simvastatin for long-term prophylaxis of cardiovascular disease22 might have been made available under such a
scheme. Its over-the-counter formulation has been restricted to 10-mg
tablets, too low a dose for a full beneficial effect, and pharmacists are
required to ask a few simple questions about the patient’s clinical condition before supplying it, without further monitoring of progress.
Under a PCS classification, the pharmacist would be required to see the
patient regularly, at least in the early stages, to titrate the dose in the
absence of adverse effects (for example, muscle pains), and to warn
about possible drug– drug interactions; contrary to widespread
opinion, one need not monitor the serum cholesterol concentration in
these circumstances.22,23 If necessary, the GP could be asked to advise.
The availability of a PCS category intermediate between PoM and P
would also allow newly switched drugs to be subjected to more careful
scrutiny. Despite initial concerns, over-the-counter levonorgestrel for
emergency contraception has established itself as safe and effective,
and there has been no increase in the frequency of episodes of unprotected sex or any reduction in the use of other more reliable contraceptive methods as a result of its being available over the counter.24 If
British Medical Bulletin 2009;90
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J. K. Aronson
sildenafil were accorded PCS status, in time it would or would not
prove itself in a similar fashion and could then be switched ‘from PCS
to P’ or ‘from PCS to PoM’. During this probationary period, the
manufacturers would be required to provide the Licensing Authority
with information about sales and post-marketing pharmacovigilance.
In some cases (e.g. sumatriptan) the Medicines and Healthcare products Regulatory Agency already asks drug companies to carry out
feasibility studies to troubleshoot potential problems before P status is
granted.
A private scheme whereby pharmacists can issue Viagra on a patient
group direction is already available in some parts of the UK.25 By all
means let sildenafil be made available over the counter, but in
small pack sizes, on a probationary basis, and under cover of a new
category—PCS medicines—intermediate between PoM and P.
Acknowledgements
I am grateful to Robin Ferner and Nigel Baber for helpful comments
on an early draft of this article.
Conflict of interest
J.K.A. is President of the British Pharmacological Society, but the views
that he expresses here should not necessarily be taken to represent the
views of other members of that Society.
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