Drug nomenclature

Drug nomenclature is the systematic naming of drugs, especially pharmaceutical drugs. Drugs, in the majority of circumstances, have 3 types of names: chemical names, the most important of which is the IUPAC name; generic or nonproprietary names, the most important of which are the International Nonproprietary Names (INNs); and trade names, which are brand names.[1] Generic names for drugs are nowadays constructed out of affixes and stems that classify the drugs into different categories and also separate drugs within categories.[2] A marketed drug might also have a company code or compound code.[3]


Chemical names

The chemical names are the scientific names, based on the molecular structure of the drug. There are various systems of chemical nomenclature and thus various chemical names for any one substance. The most important is the IUPAC name. Chemical names are typically very long and too complex to be commonly used in referring to a drug.[1] Sometimes, a company that is developing a drug might give the drug a company code,[3] which is used to identify the drug while it is in development. For example, CDP870 is UCB’s company code for Cimzia.[1] Many of these codes, although not all, have prefixes that correspond to the company name.

Nonproprietary names

During development, the company will apply for regulatory approval of the drug by the relevant national regulatory agency (such as the U.S. Food and Drug Administration [FDA]), and it will apply for a generic (nonproprietary) name for that country (such as the United States Adopted Name [USAN] or Japanese Accepted Name [JAN]). It will also apply for an International Nonproprietary Name (INN) through the World Health Organization (WHO). Nowadays the national nonproprietary names are usually the same as the INN. The generic names usually indicate via their stems what drug class the drug belongs to.[4] For example, one can tell that aciclovir is an antiviral drug because its name ends in the -vir suffix.

Combination drug products

For combination drug products—those with 2 or more drugs combined into 1 dosage form—single nonproprietary names beginning with "co-" exist in both British Approved Name (BAN) form and in a formerly maintained USP name called the pharmacy equivalent name (PEN). Otherwise the 2 names are simply both given, joined by hyphens or slashes. For example, suspensions combining trimethoprim and sulfamethoxazole are called either trimethoprim/sulfamethoxazole or co-trimoxazole. Similarly, co-codamol is codeine-acetaminophen, and co-triamterzide is triamterene-hydrochlorothiazide. The USP ceased maintaining PENs, but the similar "co"-prefixed BANs are still current.

Trade names

For drugs that make it all the way through development, testing, and regulatory acceptance, the pharmaceutical company then gives the drug a trade name. The term trade name is a standard term in the pharmaceutical industry for a brand name or trademark name. For example, Lipitor is Pfizer's trade name for atorvastatin, a cholesterol-lowering medication.

Publication policies for nonproprietary and proprietary names

In the scientific literature, there is a set of strong conventions for drug nomenclature regarding the letter case and placement of nonproprietary and proprietary names, as follows:

For example, the 2015 American Society of Hematology (ASH) publication policies say,[5] "Non-proprietary (generic/scientific) names should be used and should be lowercase."[5] ... "[T]he first letter of the name of a proprietary drug should be capitalized."[5] ... "If necessary, you may include a proprietary name in parentheses directly following the generic name after its first mention."[5]

These conventions are commonly ignored or botched, either because the writer was unaware of their existence or because the writer is trying to sell a particular product. Thus it is not uncommon on the Web to see nonproprietary names capitalized, to see trade names without nonproprietary names given, or to see the placement reversed (with the nonproprietary name in parentheses trailing the trade name).

Valid exceptions to the general pattern occur when a nonproprietary name starts a sentence (and thus takes a capital), when a proprietary name has intercapping (for example, GoLYTELY, MiraLAX), or when tall-man letters are used within nonproprietary names to prevent confusion of similar names (for example, predniSONE versus predniSOLONE).


Sample of different drug names
Chemical Name Generic Name Example brand Name
N-acetyl-p-aminophenol paracetamol
acetaminophen (US, JP)
(RS)-2-(4-(2-methylpropyl)phenyl)propanoic acid ibuprofen Motrin
(2R,3S,4R,5R,8R,10R,11R,12S,13S,14R)-13-[(2,6-dideoxy-3-C-methyl-3-O-methyl-α-L-ribo-hexopyranosyl)oxy]-2-ethyl-3,4,10-trihydroxy-3,5,6,8,10,12,14-heptamethyl-11-[[3,4,6-trideoxy-3-(dimethylamino)-β-D-xylo-hexopyranosyl]oxy]-1-oxa-6-azacyclopentadecan-15-one azithromycin Zithromax
ethyl 4-(8-chloro-5,6-dihydro-11H-benzo[5,6]cyclohepta[1,2-b]pyridin-11-ylidene) -1-piperidinecarboxylateloratadineClaritin
2-acetoxybenzoic acid acetylsalicylic acid Aspirin
3-(2-methoxyphenoxy)propane-1,2-diol guaifenesin Mucinex
2-(diphenylmethoxy)-N,N-dimethylethylamine hydrochloridediphenhydramineBenadryl
3-[(4,5-dihydro-1H-imidazol-2-yl)methyl]-6-(1,1-dimethylethyl)-2,4-dimethyl-phenol hydrochlorideoxymetazolineVisine
(3R,5R)-7-[2-(4-fluorophenyl)-3-phenyl-4-(phenylcarbamoyl)-5-propan-2-ylpyrrol-1-yl]-3,5-dihydroxyheptanoic acidatorvastatinLipitor
4,5α-epoxy-3-methoxy-17-methylmorphinan-6-one tartrate (1:1) hydrate (2:5)acetaminophen and hydrocodoneVicodin

Generic naming systems and affixes

The earliest roots of standardization of generic names for drugs began with city pharmacopoeias, such as the London, Edinburgh, Dublin, Hamburg, and Berlin Pharmacopoeias. The fundamental advances in chemistry during the 19th century made that era the first time in which what we now call chemical nomenclature, a huge profusion of names based on atoms, functional groups, and molecules, was necessary or conceivable. In the second half of the 19th century and the early 20th, city pharmacopoeias were unified into national pharmacopoeias (such as the British Pharmacopoeia, United States Pharmacopeia, Pharmacopoeia Germanica (PhG or PG), Italian Pharmacopeia, and Japanese Pharmacopoeia) and national formularies (such as the British National Formulary, the Australian Pharmaceutical Formulary, and the National Formulary of India). International pharmacopeias, such as the European Pharmacopoeia and the International Pharmacopoeia of the World Health Organization (WHO), have been the next level.

In 1953 the WHO created the International Nonproprietary Name (INN) system, which issues INNs in various languages, including Latin, English, French, Spanish, Russian, Chinese, and Arabic. Several countries also have national-level systems for creating generic drug names, including the British Approved Name (BAN) system, the Australian Approved Name (AAN) system, the United States Adopted Name (USAN) system (which is mostly the same as the United States Pharmacopeia (USP) system), and the Japanese Accepted Name (JAN) system. At least several of these national-level Approved Name/Adopted Name/Accepted Name systems were not created until the 1960s, after the INN system already existed. In the 21st century, increasing globalization is encouraging maximal rationalization for new generic names for drugs, and there is an increasing expectation that new USANs, BANs, and JANs will not differ from new INNs without especial justification.

During the first half of the 20th century, generic names for drugs were often coined by contracting the chemical names into fewer syllables. Such contraction was partially, informally, locally standardized, but it was not universally consistent. In the second half of the 20th century, the nomenclatural systems moved away from such contraction toward the present system of stems and affixes that show chemical relationships.

Generic names are used for a variety of reasons. They provide a clear and unique identifier for active chemical substances, appearing on all drug labels, advertising, and other information about the substance. Relatedly, they help maintain clear differentiation between proprietary and nonproprietary aspects of reality, which people trying to sell proprietary things have an incentive to obfuscate; they help people compare apples to apples. They are used in New Drug Applications for the US Food and Drug Administration, in scientific descriptions of the chemical, in discussions of the chemical in the scientific literature and descriptions of clinical trials.[2]

Biopharmaceuticals have posed a challenge in nonproprietary naming because unlike smaller molecules made with total synthesis or semisynthesis, there is less assurance of complete fungibility between products from different manufacturers. Somewhat like how wine may vary by strain of yeast and year of grape harvest, each one can be subtly different because living organisms are an integral part of production. The WHO MedNet community continually works to augment its system for biopharmaceuticals to ensure continued fulfillment of the goals served by having nonproprietary names.[6] In recent years the development of the Biological Qualifier system has been an example.[6]

The prefixes and infixes have no pharmacological significance and are used to separate the drug from others in the same class. Suffixes or stems may be found in the middle or more often the end of the drug name, and normally suggest the action of the drug. Generic names often have suffixes that define what class the drug is.[2]

See also Time release technology > List of abbreviations for formulation suffixes.

List of drug name stems and affixes

More comprehensive lists can be found at the National Library of Medicine[7] or in Appendix VII of the USP Dictionary.

Stem Drug class Example
-vir Antiviral drug[2] aciclovir
-cillin Penicillin-derived antibiotics penicillin, carbenicillin, oxacillin[8]
cef- Cephem-type antibiotics cefazolin
-mab Monoclonal antibodies[2] trastuzumab, ipilimumab
-ximab Chimeric antibody that responds to more than one antigen[2] infliximab
-zumab humanized antibody[9] natalizumab, bevacizumab
-tinib Tyrosine-kinase inhibitors[2] erlotinib, crizotinib
-vastatin HMG-CoA reductase inhibitor[2] atorvastatin
-prazole Proton-pump inhibitor[2] omeprazole
-lukast Leukotriene receptor antagonists[2] zafirlukast, montelukast
-grel- Platelet aggregation inhibitor[2] clopidogrel, ticagrelor
-axine Dopamine and serotonin–norepinephrine reuptake inhibitor[2] venlafaxine
-oxetine Antidepressant related to fluoxetine[2] duloxetine, reboxetine
-sartan Angiotensin receptor antagonists[2] losartan, valsartan
-pril Angiotensin converting enzyme inhibitor[2] captopril, lisinopril
-oxacin Quinolone-derived antibiotics levofloxacin, moxifloxacin
-barb- Barbiturates Phenobarbital, secobarbital
-xaban Direct Xa inhibitor apixaban, rivaroxaban
-afil Inhibitor of PDE5 with vasodilator action sildenafil, tadalafil
-prost- Prostaglandin analogue latanoprost, unoprostone
-ine chemical substance atropine, quinine
-parib PARP inhibitor olaparib, veliparib
-tide Peptides and glycopeptides Nesiritide, Octreotide

Example breakdown of a drug name

If name of the drug solanezumab were to be broken down, it would be divided into two parts like this: solane-zumab. -Zumab is the suffix for humanized monoclonal antibody.[9] Monoclonal antibodies by definition contain only a single antibody clone and have binding specificity for one particular epitope.[10] In the case of solanezumab, the antibody is designed to bond to the amyloid-β peptides which make up protein plaques on the neurons of people with Alzheimer's disease.


Most commonly, a nonproprietary drug name has one widely agreed pronunciation in each language. For example, doxorubicin is consistently /ˌdɒksˈrbsɪn/ in English.[11][12] Trade names almost always have one accepted pronunciation, because the sponsoring company who coined the name has an intended pronunciation for it.

However, it is also common for a nonproprietary drug name to have two pronunciation variants, or sometimes three. For example, for paracetamol, both /ˌpærəˈstəmɒl/ and /ˌpærəˈsɛtəmɒl/[12] are common, and one medical dictionary gives /pærˌæsˈtæmɒl/.[13]

Some of the variation comes from the fact that some stems and affixes have pronunciation variants. For example, the aforementioned third (and least common) pronunciation for paracetamol reflects the treatment of the acet affix as /ˈæst/ rather than /əˈst/ (both are accepted for acetyl[13][11]). Other variations arise from the degree to which spelling pronunciation plays a role in individuals' use of the words. When variations interact in speech, it sometimes produces the familiar reaction of "You say /təˈmeɪtoʊ/, I say /təˈmɑːtoʊ/." Nevertheless, accepted variants for drug names reflect plausibility regarding chemistry and pharmacy. For example, just as /ˈtɒmət/ is not an accepted third option for tomato, /fəˈnɒθiəˌzn/ is an implausible guess for phenothiazine, given that pheno- and thiazine are predictable (thus /ˌfnˈθəzn/).

The World Health Organization does not give suggested pronunciations for its INNs, but familiarity with the typical sounds and spellings of the stems and affixes often points to the widely accepted pronunciation of any given INN. For example, abciximab is predictably /æbˈsɪksmæb/, because for INNs ending in -ciximab, the /ˈsɪksmæb/ sound is familiar. The United States Pharmacopeia gives suggested pronunciations for most USANs in its USP Dictionary, which is published in annual editions. Medical dictionaries give pronunciations of many drugs that are both commonly used and have been commercially available for a decade or more, although many newer drugs or less common drugs are not entered. Pharmacists also have access to pronunciations from various clinical decision support systems such as Lexi-comp.

See also


  1. 1 2 3 "How drugs are named". UCB. 2011-12-09. Retrieved 2013-01-01.
  2. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 "Generic naming". American Medical Association. Retrieved 2013-01-01.
  3. 1 2 Lowe, Derek (23 October 2006). "Experimental Compound Codes". Science. Retrieved 20 November 2015.
  4. Silverman, HM (2007-04-01). "Overview of Generic Drugs and Drug Naming". Merck & Co. Retrieved 2013-01-01.
  5. 1 2 3 4 "Information for Late-Breaking Abstract Authors". American Society of Hematology. 2014. Retrieved 23 November 2015.
  6. 1 2 World Health Organization, INN and Biologicals, retrieved 2016-06-16.
  7. "Generic Name Stems". National Library of Medicine.
  8. "Penicillin". Drugs.com. 2010-12-15. Retrieved 2013-01-01.
  9. 1 2 Gylys BA & Wedding ME (2005). "-zumab". Taber's Cyclopedic Medical Dictionary/medical Terminology: A Systems Approach. Medicus Media. p. 2371. ISBN 0803613245.
  10. http://www.piercenet.com/method/antibody-production-immunogen-preparation
  11. 1 2 Merriam-Webster, Merriam-Webster's Medical Dictionary, Merriam-Webster.
  12. 1 2 Oxford Dictionaries, Oxford Dictionaries Online, Oxford University Press.
  13. 1 2 Elsevier, Dorland's Illustrated Medical Dictionary, Elsevier.
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