Drug Nomenclature
A drug generally has three categories of names:
(a) Chemical name It describes the sub
stance che mically, e.g. 1-(Isopropylamino)-3
(1-naphthyloxy) propan-2-ol for propranolol.
This is cumber some and not suitable for use
in prescribing. A code name, e.g. RO 151788
(later named flumazenil) may be assigned by
the manufacturer for con venience and simplicity
before an approved name is coined.
(b) Non-proprietary name It is the name
accep ted by a competent scientific body/
authority, e.g. the United States Adopted Name
(USAN) by the USAN council. Similarly,
there is the British Approved name (BAN) of
a drug. The non-proprietary names of newer
drugs are kept uniform by an agreement to use
the Recommen ded International Nonproprie tary
Name (rINN) in all member countries of the
WHO. The BAN of older drugs as well has
now been modified to be commensurate with
rINN. However, many older drugs still have
more than one non-proprietary names, e.g.
‘meperidine’ and ‘pethidine’ or ‘lidocaine’
and ‘lignocaine’ for the same drugs. Until
the drug is included in a pharmacopoeia, the
nonproprie tary name may also be called the
approved name. After its appearance in the
official publication, it becomes the official
name.
In common parlance, the term generic
name is used in place of nonproprietary name.
Etymolo gically this is incorrect: ‘generic’ should be applied to the chemical or pharma
cological group (or genus) of the compound,
e.g. pheno thiazines, tricyclic anti depressants,
aminoglycoside anti bio tics, etc. However, this
misnomer is widely accepted and used even
in official parlance.
(c) Proprietary (Brand) name It is the
name assig ned by the manufacturer(s) and is
his property or trade mark. One drug may
have mul tiple pro prietary names, e.g. AMCARD,
AMLOGARD, AMLOCOR, AMLONG, AMLOPIN,
AMLOVAS, STAMLO for amlodipine from different
manufac turers. Brand names are designed to
be catchy, short, easy to remember and often
suggestive, e.g. LOPRESOR suggesting drug for
lowering blood pressure. Brand names gener
ally differ in diffe rent countries, e.g. timolol
maleate eye drops are marketed as TIMOPTIC in
USA but as GLUCOMOL in India. Even the same
manufacturer may mar ket the same drug under
different brand names in different countries. In
addition, combined formulations have their own
multiple brand names. This is responsible for
much confusion in drug nomen clature.
There are many arguments for using the
nonproprietary name in prescribing: uniformity,
convenience, economy and better comprehen sion
(propranolol, sotalol, timolol, pindolol, meto
prolol, acebutolol, atenolol are all b blockers,
but their brand names have no such similarity).
Drugs marketed under nonproprietary name
(called generic products) are much cheaper than
their branded counterparts, partly because the
manufacturer invests a lot of money in promot
ing the brand name. However, when a drug is
prescribed by the generic name, the chemist
is free to dispense the generic product from
any manufacturer, but not so when the drug is
prescribed by a brand name. Thus, when it is
important to ensure consistency of the product
in terms of quality and bioavailability, etc. and
especially when official control over quality
of manufac tured products is not rigorous, it
is better to prescribe by the dependable brand
name
Drug comPendIa
These are compilations of information on drugs
in the form of monographs; without going into
the theoretical concepts, mechanisms of action
and other aspects which help in understanding
the subject. Pharmacopoeias and Formularies
are broughtout by the Government in a country,
hold legal status and are called official compen
dia. In addition, some nonofficial compendia
are published by professional bodies, which
are supplementary and dependable sources of
information about drugs.
Pharmacopoeias
They contain description of
chemical structure, molecular weight, physical
and chemical characteristics, solubility, identifi
cation and assay methods, standards of purity,
storage conditions and dosage forms of officially
approved drugs in a country. They are useful to
drug manufacturers and regulatory authorities,
but not to doctors, most of whom never see
a pharmacopoeia. Examples are Indian (IP),
British (BP), European (Eur P), United States
(USP) pharmacopoeias.
Formularies
Generally produced in easily
carried booklet form, they list indications, dose,
dosage forms, contraindications, precautions,
adverse effects and storage of selected drugs
that are available for medicinal use in a country.
Drugs are categorized by their therapeutic class.
Some rational fixeddose drug combinations
are included. A brief commentary on the
drug class and clinical conditions in which
they are used generally precedes specifics of
individual drugs. Brief guidelines for treatment
of selected conditions are provided. While British
National Formulary (BNF) also lists brand names
with costs, the National Formulary of India (NFI)
does not include these. Most formularies have
informative appendices as well. Formularies can
be consid erably helpful to prescribers.
Martindale: The Complete Drug Reference
(Extrapharmacopoeia) Published every 2–3
years by the Royal Pharmaceutical Society of
Great Britain, this nonofficial compendium is an exhaustive and updated compilation of un
biased information on medicines used/registered
all over the world. It includes new launches and
contains pharmaceutical, pharma cological as well
as therapeutic information on drugs, which can
serve as a reliable reference book.
EssentIal medIcInes (drugs)
concePt
The WHO has defined Essential Medicines
(drugs) as “those that satisfy the priority
healthcare needs of the population.” They
are selected with due regard to public health
relevance, evidence on efficacy and safety,
and comparative cost effective ness. Essential
medicines are intended to be available within
the context of functioning health systems at all
times and in adequate amounts, in appropriate
dosage forms, with assured quality and adequate
information, and at a price the individual and
the community can afford.
It has been realized that only a handful of
medicines out of the multitude available can
meet the health care needs of majority of the
people in any country, and that many well
tested and cheaper medicines are equally (or
more) efficacious and safe as their newer more
expensive congeners. For optimum utilization of
resources, governments (especially in developing
countries) should concentrate on these medicines
by identifying them as Essential medicines. The
WHO has laid down criteria to guide selection
of an essential medicine.*
(a) Adequate data on its efficacy and safety should be
available from clinical studies.
(b) It should be available in a form in which quality, includ
ing bioavailability, and stability on storage can be assured.(c) Its choice should depend upon pattern of prevalent
diseases; availability of facilities and trained personnel;financial resources; genetic, demographic and environ
mental factors.
(d) In case of two or more similar medicines, choice
should be made on the basis of their relative efficacy,
safety, quality, price and availability. Costbenefit ratio
should be a major consideration.
(e) Choice may also be influenced by comparative pharma
cokinetic properties and local facilities for manufacture
and storage.
(f) Most essential medicines should be single compounds.
Fixed ratio combination products should be included only
when dosage of each ingredient meets the requirements
of a defined population group, and when the combina
tion has a proven advantage in therapeutic effect, safety,
adherence or in decreasing the emergence of drug resistance.
(g) Selection of essential medicines should be a continu
ous process which should take into account the changing
priorities for public health action, epidemiological conditions
as well as availability of better medicines/formulations and
progress in pharmacological knowledge.
(h) Recently, it has been emphasized to select essential
medicines based on rationally developed treatment guide
lines.
To guide the member countries, the WHO
brought out its first Model List of Essential
Drugs along with their dosage forms and
strengths in 1977 which could be adopted
after suitable modifications according to local
needs. This has been revised from time to time
and the current is the 20th list (2017)$ which
has 433 medicines, including 25 fixed dose
drug combinations (FDCs). India produced its
National Essential Drugs List in 1996, and has
revised it in 2011, and now in 2015 with the
title “National List of Essential Medicines”.£
The latest list includes 376 medicines, of which
20 are FDCs. These medicines have been
marked into 3 categories for being available
at primary, secondary and tertiary levels of
health care facility.
Adoption of the essential medicines list for
procurement and supply of medicines, especially
in the public sector healthcare system, has
resulted in improved availability of medicines,
cost saving and more rational use of drugs.
Prescription and non-prescription drugs
As per drug rules, majority of drugs includ
ing all antibiotics must be sold in retail only
against a prescription issued to a patient by a
registered medical practitioner. These are called
‘prescription drugs’, and in India they have
been placed in the schedule H of the Drugs
and Cosmetic Rules (1945) as amended from
time to time. However, few drugs like simple
analgesics (paracetamol aspirin), antacids, laxa
tives (senna, lactulose), vitamins, ferrous salts,
etc. are considered relatively harmless, and can
be procured without a prescription. These are
‘nonprescription’ or ‘over thecounter’ (OTC)
drugs; can be sold even by grocery stores.
Orphan Drugs
These are drugs or biological products for
diagnosis/treatment/ prevention of a rare disease or condi
tion, or a more common disease (endemic only in resource
poor countries or areas) for which there is no reasonable
expectation that the cost of developing and marketing it
will be recovered from the sales of that drug. As per Or
phan Drug Amendment (1983) Act of USA, a rare disease/
condition is one that affects less than 0.2 million people
in the USA. Though these drugs may be life saving for
some patients, they are commercially difficult to obtain as
a medicinal product. Governments in developed countries
offer tax benefits and other incentives to pharmaceutical
companies for developing and marketing orphan drugs.
Orphan drug status has been awarded to many drugs in the
USA, Europe and some other countries. Few examples of
drugs granted ‘Orphan Drug’ status are listed in the box.
Drug nomenclature in pharmacology
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