The cascade and human
generic products
What is it?
The Cascade is a long-standing legal flexibility
providing a rational balance between the legislative requirement for
veterinary surgeons to prescribe and use authorised veterinary medicines
where they are available, and the need for professional freedom to prescribe
other products where they are not. It is intended to increase the range of
medicines available for veterinary use.
Why is it important to
use authorised medicines?
Animal species may have many physiological differences
from humans and from each other. As a result they each may react differently
to medicines. The authorisation system for veterinary medicines requires a
product to have proven quality and effectiveness and, most importantly,
safety for the animal, the user (vet, farmer, pet owner etc.), the
environment and, for food animals, the consumer of animal produce. This
assurance has to be provided for each species and each indication on the
label.
In addition, animal medicines containing the same active
ingredient as human medicines may be formulated differently. For instance,
the formulation needs to ensure they are properly absorbed through the gut
(which, for example, is rather shorter in a cat than a human). Human
medicine formulations may contain different excipients or have different
bioavailability from veterinary medicines. Using a product which is not
authorised for animals therefore, increases the risk of harm to the patient.
In addition, the cost of developing a medicine for animal
use is high and can involve much research and many tests not carried out for
human medicines.
The use of human medicines, in place of the equivalent
authorised veterinary medicine, can only be done by referring to the
information on medicine use provided by the animal medicine companies.
Assuming the data is transferable in this way is potentially hazardous and
doing so takes advantage of work done by the animal medicine industry
without paying for it. This means that those users abiding by the rules are
subsidising those who do not, and such abuse diverts essential funding away
from future research and development for new veterinary medicines.
It is important to address the potential confusion with
the use of the word “generic”. Authorised veterinary generics exist
legitimately which can be used by vets as other authorised animal medicines.
However, human generic medicines that are similar to the authorised
veterinary medicines may not be used unless there is no suitable veterinary
medicine available.
The Cascade provides a legal mechanism allowing
veterinary surgeons to use their clinical judgement to prescribe a suitable
medicine where no authorised medicine exists. Use and prescription by vets
of human generic medicines where a suitable veterinary product is available
is a criminal offence and contrary to the RCVS Guide to Professional
Conduct.
Vets remain entirely responsible for the treatment of
animals under their care; use of a medicine under the cascade should be
capable of being supported by clear auditable clinical evidence to justify
the vet’s decision.
What do vets need to do
to comply with the cascade?
If there is no medicine authorised in the UK for a
specific condition, the veterinary surgeon responsible for treating the
animal(s) may, in order to mitigate unacceptable suffering, treat the
animal(s) in accordance with the following sequence:
(a) a veterinary medicine authorised in the UK for
use in another animal species or for a different condition in the same
species; or, if there is no such product;
(b) either:
(i) a medicine authorised in the UK for human
use, or
(ii) in accordance with an import certificate
from VMD, a veterinary medicine from another Member State; or, if
there is no such product;
(c) a medicine prepared extemporaneously, by a vet,
pharmacist or a person holding an appropriate manufacturer’s
authorisation.
If the animal(s) are food-producing animals, then the
following additional conditions apply:
-
the treatment in any particular case is restricted to
animals on a single holding
-
any medicine imported from another Member State must
be authorised for use in a food-producing species in the other Member
State
-
the pharmacologically active substances contained in
the medicine must have MRLs
-
the prescribing vet must specify an appropriate
withdrawal period – statutory minimums are in the Regulations
-
the prescribing vet must keep specified records.
A medicine prescribed in accordance with the cascade may
be administered by the prescribing vet or by a person acting under their
direction. Responsibility for the prescription and use of the medicine
remains with the prescribing veterinary surgeon.
For further information, please see the VMD’s Veterinary
Medicines Guidance Note 15, “Controls on the Administration of Veterinary
Medicines”, available from
www.vmd.gov.uk
Animals need medicines to help prevent disease and to
help treat them if they do fall ill. All species deserve the benefit of
medicinal products which have been specifically developed and authorised for
their treatment. The cascade ensures this happens wherever possible, but
also gives flexibility for veterinary surgeons to use their clinical
judgement to prescribe a medicine where no veterinary authorised medicine
exists.
November 2006
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