Drug nomenclature
Drug nomenclature is the systematic naming of drugs, especially pharmaceutical drugs. In the majority of circumstances, drugs 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 ; and trade names, which are brand names. 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. A marketed drug might also have a company code or compound code.
Types
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 in speech or in prose documents. For example, "1--3- propan-2-ol" is a chemical name for propranolol. Sometimes, a company that is developing a drug might give the drug a company code, which is used to identify the drug while it is in development. For example, CDP870 was UCB’s company code for certolizumab pegol; UCB later chose "Cimzia" as its trade name. Many of these codes, although not all, have prefixes that correspond to the company name.Nonproprietary (generic) 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 ; and it will apply for a generic name for that country, such as the United States Adopted Name or Japanese Accepted Name. It will also apply for an International Nonproprietary Name through the World Health Organization.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. 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 two or more drugs combined into a single dosage form—single nonproprietary names beginning with "co-" exist in both British Approved Name form and in a formerly maintained USP name called the pharmacy equivalent name. Otherwise the two 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-paracetamol, and co-triamterzide is triamterene-hydrochlorothiazide. The USP ceased maintaining PENs, but the similar "co"-prefixed BANs are still current.Drug brands
For drugs that make it all the way through development, testing, and regulatory acceptance, the pharmaceutical company then gives the drug a trade name, which 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. Many drugs have multiple trade names, reflecting marketing in different countries, manufacture by different companies, or both. Thus the trade names for atorvastatin include not only Lipitor but also Atocor.Legal regulation
Drug names are often subject to legal regulation, including approval for new drugs and on packaging to establish clear rules about adulterants and fraudulent or misleading labeling. A national formulary is often designated to define drug names for regulatory purposes. The legally approved names in various countries include:- Australian Approved Name
- British Approved Name
- Dénomination Commune Française
- Denominazione Comune Italiana
- Japanese Accepted Name
- United States Adopted Name
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:- Nonproprietary names begin in lowercase; trade names begin with a capital.
- Unbiased mentions of a drug place the nonproprietary name first and follow it with the trade name in parentheses, if relevant.
- * This pattern is important for the scientific literature, where conflict of interest is disclosed or avoided. The authors reporting on a study are not endorsing any particular brand of drug. They will often state which brand was used, for methodologic validity, but they do so in a way that makes clear the absence of endorsement.
Valid exceptions to the general pattern occur when a nonproprietary name starts a sentence, when a proprietary name has intercapping, or when tall-man letters are used within nonproprietary names to prevent confusion of similar names.
Examples
| Chemical Name | Generic Name | Example Brand Name |
| N-acetyl-p-aminophenol | paracetamol acetaminophen | Tylenol |
| -2-propanoic acid | ibuprofen | Motrin |
| -13--2-ethyl-3,4,10-trihydroxy-3,5,6,8,10,12,14-heptamethyl-11-oxy]-1-oxa-6-azacyclopentadecan-15-one | azithromycin | Zithromax |
| ethyl 4- -1-piperidinecarboxylate | loratadine | Claritin |
| 2-acetoxybenzoic acid | acetylsalicylic acid | Aspirin |
| 3-propane-1,2-diol | guaifenesin | Mucinex |
| 2--N,N-dimethylethylamine hydrochloride | diphenhydramine | Benadryl |
| 3--6--2,4-dimethyl-phenol hydrochloride | oxymetazoline | Visine |
| -7--3,5-dihydroxyheptanoic acid | atorvastatin calcium | Lipitor |
| 4,5α-epoxy-3-methoxy-17-methylmorphinan-6-one tartrate hydrate | acetaminophen and hydrocodone | Vicodin |
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 and national formularies. International pharmacopeias, such as the European Pharmacopoeia and the International Pharmacopoeia of the World Health Organization, have been the next level.In 1953 the WHO created the International Nonproprietary Name 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 system, the Australian Approved Name system, the United States Adopted Name system, and the Japanese Accepted Name 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 special 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.
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. In recent years the development of the Biological Qualifier system has been an example.
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.
See also Time release technology > List of abbreviations for formulation suffixes.
List of stems and affixes
More comprehensive lists can be found at the National Library of Medicine's Drug Information Portal or in Appendix VII of the USP Dictionary.| Stem | Drug class | Example |
| -vir | Antiviral drug | aciclovir, oseltamivir |
| -cillin | Penicillin-derived antibiotics | penicillin, carbenicillin, oxacillin |
| cef- | Cephem-type antibiotics | cefazolin |
| -mab | Monoclonal antibodies | trastuzumab, ipilimumab |
| -ximab | Chimeric antibody, in which the design of the therapeutic antibody incorporates parts of multiple different antibodies, for example, in the case of infliximab, variable regions from a mouse anti-TNF antibody and constant regions from human antibodies | infliximab |
| -zumab | humanized antibody | natalizumab, bevacizumab |
| -anib | Angiogenesis inhibitors | Pazopanib, Vandetanib |
| -ciclib | Cyclin-dependent kinase 4/CDK6 inhibitors | palbociclib, ribociclib |
| -degib | hedgehog signaling pathway inhibitors | Vismodegib, Sonidegib |
| -denib | IDH1 and IDH2 inhibitors | Enasidenib, Ivosidenib |
| -lisib | Phosphatidylinositol 3-kinase inhibitors | alpelisib, buparlisib |
| -parib | PARP inhibitor | olaparib, veliparib |
| -rafenib | BRAF inhibitors | Sorafenib, Vemurafenib |
| -tinib | Tyrosine-kinase inhibitors | erlotinib, crizotinib |
| -zomib | proteasome inhibitors | bortezomib, carfilzomib |
| -vastatin | HMG-CoA reductase inhibitor | atorvastatin |
| -prazole | Proton-pump inhibitor | omeprazole |
| -lukast | Leukotriene receptor antagonists | zafirlukast, montelukast |
| -grel- | Platelet aggregation inhibitor | clopidogrel, ticagrelor |
| -axine | Dopamine and serotonin–norepinephrine reuptake inhibitor | venlafaxine |
| -olol | Beta-blockers | metoprolol, atenolol |
| -oxetine | Antidepressant related to fluoxetine | duloxetine, reboxetine |
| -sartan | Angiotensin receptor antagonists | losartan, valsartan |
| -pril | Angiotensin converting enzyme inhibitor | 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 |
| -tide | Peptides and glycopeptides | Nesiritide, Octreotide |
| -vec | Gene Therapy vectors | Alipogene tiparvovec |
| -ast | asthma | |
| -imsu | immuno suppressants | |
| -caine | local anesthetic | |
| -in | inhibitor |
Example breakdown of a drug name
If the 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. Monoclonal antibodies by definition contain only a single antibody clone and have binding specificity for one particular epitope. 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.Pronunciation
Most commonly, a nonproprietary drug name has one widely agreed pronunciation in each language. For example, doxorubicin is consistently in English. 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 and are common, and one medical dictionary gives.
Some of the variation comes from the fact that some stems and affixes have pronunciation variants. For example, the aforementioned third pronunciation for paracetamol reflects the treatment of the acet affix as rather than .
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, because for INNs ending in -ciximab, the 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.