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DOCTORS in Britain who wish to prescribe suntan lotions are forced to
base their choice of prescription on a welter of confusing, misleading and
sometimes inaccurate information in the official ‘bibles’ of pharmacology,
investigations by New Å®ÉúСÊÓƵ have found.

The findings emerge in the wake of reports last month in the Drug and
Therapeutic Bulletin – published by the consumer magazine Which? and sent
to all doctors – that manufacturers of commercially available suntan lotions
provide customers with inadequate information about the extent to which
the lotions will protect skin from harmful solar radiation that can cause
cancers.

Doctors usually make informed decisions about which medicines they should
prescribe by referring to the Monthly Index of Medical Specialities (MIMS)
or the British National Formulary (BNF), which is updated every six months.
However, investigations by New Å®ÉúСÊÓƵ show that, like the labels on commercial
sunscreens, these two ‘bibles’ of pharmacology, which are sent to all general
practitioners, offer inadequate and confusing information on sunscreens.
In some cases, the information is incorrect.

There are two forms of harmful solar radiation – Ultraviolet A and Ultraviolet
B. Ultraviolet B causes sunburn, and both can cause skin cancers and wrinkling.
The main finding of the Drug and Therapeutics Bulletin in its investigations
of 15 sunscreen products was that in nine cases, the manufacturers had insufficient
data about the ability of their product to filter out UVA.

Moreover, the bulletin found, the so-called ‘Sun Protection Factors’
– numbers from 2 to 15 on product labels which in fact only reflect the
degree of protection that a suncream affords against UVB – were meaningless
because manufacturers of different products use different and incompatible
analytical tests to derive the values.

Manufacturers resist publishing a ‘Sun Protection Factor’ for UVA on
the grounds that the validity of the so-called ‘tape test’, once employed
to ascertain the figure, is now in doubt.

In the same way, both publications are vague about the properties of
the sunscreens prescribable through the National Health Service. MIMS names
products that ‘have some UVA protection as well as good UVB protection’,
but it gives no equivalent of the Sun Protection Factor for UVA in the relevant
entries. The BNF (No 18) says merely that the Sun Protection Factor ‘provides
some guidance on the degree of protection offered’, but mentions neither
UVA nor UVB in this context.

Two of the 10 sunscreens listed in MIMS ‘block only UVB’, yet the same
entries advise doctors that the products are appropriate for patients suffering
from photo-dermatoses (sensitivity of skin to ultraviolet light) or undergoing
radiotherapy. In both cases, it is essential to protect against UVB and
UVA, so the information in MIMS is insufficient for doctors to prescribe
appropriately.

The publications also contain inaccuracies relating to the active ingredients
in sunscreens. Three of the 10 sunscreens listed in MIMS rely on a reflectant
called titanium dioxide, though only one entry contains this information.
One of the three sunscreens containing titanium dioxide has zinc oxide incorrectly
listed as its active ingredient for reflecting harmful radiation. The same
error occurs in the BNF.

Gwen Parr of Ciba Geigy, a Swiss-based multinational which manufactures
the Piz-Buin range of sunscreens, agreed that the information about sunscreens
was ‘a bit of a mess’ that made it hard for doctors as well as lay people
to make a rational choice. Both she and Jean Gregory of Nicholas Laboratories
said that their firms were currently reviewing their sunscreen labelling
and considering how to improve the information on their products.