How are drugs named?

Ever wondered how drugs are named? More thought goes into drug naming than you might realise.
Crafting a novel drug’s name is an important step in the drug development process. The assignment of names to pharmaceuticals in development is, in fact, an important prerequisite to marketing a drug. Any new drug aiming for market will have three different names. These three names are the chemical name, a generic name and a brand name.

Chemical names, while they can become complex, are relatively straightforward to understand. Similarly, generic names have stems that allow the type of drug or its use to be communicated with ease. The final name, that most drugs are known by once they are in the consumer market, is the brand name.

But what do the different names actually mean?

How are drugs named – Step 1: Chemical names

Perhaps the most straightforward of the naming systems, the chemical name is the scientific name for a drug, based on its structure. In practice, chemical names are rarely, if ever, used. For example, 5-[2-ethoxy-5-(4-methylpiperazin-1-ylsulfonyl)phenyl]-1- methyl-3-propyl-1,6-dihydro-7H-pyrazolo[4,3-d]pyrimidin-7-one is far too cumbersome to use and given the length, it would be more than just impractical for any extended use. Unlike the generic name for this drug which is Sildenafil.

Before moving from a chemical name to deciding on a generic name, often an internal code name will be applied to drugs for ease. As shown in our poster in collaboration with G1 Therapeutics, their drugs are internally named with the prefix G1T – before they go on to receive their generic name.

How are drugs named – Step 2: Generic names

The generic name is the first area where a company has some freedom on a name. A number of organisations approve generic names for novel drugs. The World Health Organization (WHO) will confer an International Nonproprietary Name (INN). This is the official generic naming system that started in 1953. A number of countries around the world also have national regulatory agencies that can approve generic names for that country. For example, in the United Kingdom, a British Approved Name (BAN) for a drug is the generic name for a drug. In practice nowadays, the INN and individual countries’ generic names are identical due to close collaboration between the WHO and individual pharmacopoeia. Since 2002, the BAN can be assumed to be the recommended INN.

In the case of our project with G1 Therapeutics, we analysed data from trials for two of their drugs, G1T28 and G1T38; G1T38, also known by its generic name of lerociclib and G1T28, known as trilaciclib. They both have a common stem ‘-ciclib’, denoting that they are cyclin-dependent kinase 4/CDK6 inhibitors.

The list of stems in use to denote the class of drug is extensive. From the chemical name example above, the drug has a generic name of sildenafil – the ‘-afil’ denoting its action as an inhibitor of PDE5 with vasodilator action.

In addition to a list of stems that need to be incorporated depending on the type of drug and method of action, there are also a number of rules that apply when aiming for a generic name such as avoiding certain letters or using multiple syllables. Once some potential names have been created, they can be submitted to the WHO or individual countries’ naming organisations. Those organisations will then either approve or reject the names.

How are drugs named – Step 3: Brand names

Some brand names are iconic now. Viagra (a brand name for Sildenafil) and Prozac (N-methyl-3-phenyl-3-[4-(trifluoromethyl) phenoxy]propan-1-amine, generic name fluoxetine) are two such examples.

Unlike the generic names, which are internationally recognised and endorsed, the brand name is unique to the company that is producing that drug. When a new drug is released under patent protection, it will be marketed under the brand name. Generally, this is due to the brand name being much catchier and easier to market to consumers and healthcare professionals. Once patent protection has lapsed and the drug is off-patent, other companies can file for approval to market the drug. They must use the same generic name (to reduce confusion for the consumer about the actual drug they are taking). However, they can also create their own brand name to use for their marketing.

For example, paracetamol is now an off-patent drug which you can find for sale under its generic name or a multitude of brand names such as Panadol or Calpol in the UK.

Challenges in drug naming

Naming a new drug can be a minefield, with a number of important tests that the name needs to pass before it can be allowed. Probably the most important litmus test for a brand name is its catchiness and ease of remembrance. Notable examples include the drug Glucotrol which controls glucose levels, Minocin which is a shortened brand name for the generic name minocycline, and Tamiflu, prescribed as an antiviral to prevent influenza infections.

Another key test for brand names is the relative safety of the name. Confusing similar names could have disastrous effects if there is an error in prescribing, dispensing, or taking medication. For example, Almarl (generic name: arotinolol) and Amaryl (generic name: glimepiride) are two completely different drugs; Almarl is a mixed alpha/beta blocker while Amaryl treats type 2 diabetes. Celebrex (celecoxib), Cerebyx (fosphenytoin), and Celexa (citalopram) are, in order, an anti-inflammatory, a phenytoin prodrug, and an antidepressant. Classed as “lookalikes, soundalikes”, new brand names are compared against those that already exist to try and reduce these issues.

Read more

The International Pharmacopoeia

Our work with G1

Drug naming – Pfizer

List of Confused Drug Names