page21
Guidance on prescribing
General guidance
Medicines should be prescribed only when they are
necessary,
and in all
cases the benefit of administering
the medicine should be considered in relation to the risk
involved.
This
is
particularly
important
during
pregnancy,
when the risk to both mother
and fetus
must be considered (for further details see Prescribing
in Pregnancy,
p.
19).
It
is important
to discuss treatment
options carefully
with the patient to ensure that the patient is content to
take the medicine as prescribed (see also Taking Med-
icines to Best Effect,
below).
In particular,
the patient
should be helped to distinguish the adverse effects of
prescribed drugs from the effects of
the medical
dis-
order.
When the beneficial
effects of
the medicine are
likely to be delayed,
the patient
should be advised of
this.
Taking medicines to best
effect
Difficulties
in
adherence to drug treatment
occur regardless of
age.
Factors
contributing to poor
compliance
with pre-
scribed medicines include:
.
prescription not collected or not dispensed;
.
purpose of medicine not clear;
.
perceived lack of efficacy;
.
real or perceived adverse effects;
.
patients’ perception of the risk and severity of side-
effects may differ from that of the prescriber;
.
instructions for administration not clear;
.
physical difficulty in taking medicines (e.g. swallow-
ing the medicine, handling small tablets, or opening
medicine containers);
.
unattractive formulation (e.g.
unpleasant taste);
.
complicated regimen.
The prescriber
and the patient
should agree on the
health outcomes that
the patient
desires and on the
strategy for achieving them (‘concordance’).
The pre-
scriber
should be sensitive to religious,
cultural,
and
personal
beliefs that
can affect
a patient’s acceptance
of medicines.
Taking the time to explain to the patient (and relatives)
the rationale and the potential
adverse effects of treat-
ment may improve adherence.
Reinforcement and ela-
boration of the physician’s instructions by the pharma-
cist
and other
members of
the healthcare team also
helps.
Advising the patient of the possibility of alterna-
tive treatments
may encourage the patient
to seek
advice rather than merely abandon unacceptable treat-
ment.
Simplifying the drug regimen may help;
the need for
frequent
administration
may
reduce
adherence,
although there appears to be little difference in adher-
ence between once-daily and twice-daily administra-
tion.
Combination products
reduce
the
number
of
drugs taken but at the expense of
the ability to titrate
individual doses.
Biosimilar medicines
A biosimilar medicine is a new
biological product that is similar to a medicine that has
already been authorised to be marketed (the biological
reference medicine) in the European Union.
The active
substance of
a biosimilar
medicine is similar,
but
not
identical,
to the biological
reference medicine.
Biologi-
cal
products are different from standard chemical
pro-
ducts in terms of their complexity and although theore-
tically there should be no important differences between
the biosimilar and the biological
reference medicine in
terms of safety or efficacy,
when prescribing biological
products, it is good practice to use the brand name. This
will
ensure that
substitution of
a biosimilar
medicine
does not occur when the medicine is dispensed.
Biosimilar medicines have black triangle status (T,
see
p.
12) at the time of initial marketing.
It is important to
report suspected adverse reactions to biosimilar medi-
cines using the Yellow Card Scheme (p.
12).
For biosi-
milar medicines, adverse reaction reports should clearly
state the brand name of the suspected medicine.
Complementary and alternative medicine
An
increasing amount
of
information on complementary
and alternative medicine is becoming available.
The
scope of
the BNF is
restricted to the discussion of
conventional
medicines but reference is made to com-
plementary treatments if they affect conventional
ther-
apy (e.g. interactions with St John’s wort—see Appendix
1). Further information on herbal medicines is available
at
www.mhra.gov.uk.
Abbreviation of titles
In general, titles of drugs and
preparations should be written
in full
. Unofficial abbre-
viations should not
be used as they may be misinter-
preted.
Non-proprietary titles
Where non-proprietary (‘gen-
eric’) titles are given, they should be used in prescribing.
This will
enable any suitable product to be dispensed,
thereby saving delay to the patient
and sometimes
expense to the health service.
The only exception is
where there is
a demonstrable difference in clinical
effect between each manufacturer’s version of
the for-
mulation,
making it
important
that
the patient
should
always receive the same brand; in such cases, the brand
name or the manufacturer should be stated.
Non-pro-
prietary titles should not be invented for the purposes of
prescribing generically since this can lead to confusion,
particularly in the case of
compound and modified-
release preparations.
Titles used as headings for monographs may be used
freely in the United Kingdom but in other countries may
be subject to restriction.
Many of the non-proprietary titles used in this book are
titles of
monographs in the European Pharmacopoeia,
British
Pharmacopoeia,
or
British
Pharmaceutical
Codex 1973. In such cases the preparations must com-
ply with the standard (if
any)
in the appropriate pub-
lication,
as required by the Medicines Act (Section 65).
Proprietary titles
Names followed by the symbol
c
are or
have been used as proprietary names in the
United Kingdom.
These
names
may in general
be
applied only to products supplied by the owners of the
trade marks.
BNF 61
1
General guidance