Why are drug names so long and complicated? A pharmacist explains the logic behind the nomenclature

At some point in your life, you’ll likely find yourself with a prescription from your doctor to fill. While it’s important to keep track of all the medications you’re taking, that can be hard to do when the names of so many of these drugs are difficult to pronounce and even harder to remember.

In my role as a pharmacist, I’ve helped countless patients figure out exactly which medication they were taking for what ailment. Some wonder why they were prescribed the medication in the first place, or need help differentiating between drugs with names that seem like complete gibberish.

But there is a rhyme and a reason to drug names. All prescribed medications follow a standard nomenclature that describes what the drug is made of and how it functions.

Who names drugs?

Drugs get both a brand, or proprietary, name and a generic name that is nonproprietary. Each is assigned in a slightly different process.

As long as a drug compound isn’t trademarked, drug companies decide on a proprietary brand name for the medications they sell. Usually the brand name relates to the conditions the drug is intended to treat and is easy for both providers and patients to remember but doesn’t follow a standardized naming guideline. For example, the drug Lopressor helps lower blood pressure.

On the other hand, generic drug names all follow a standard nomenclature that helps medical providers and researchers more easily recognize and classify the drug. Lopressor, for example, has a generic name of metoprolol tartrate. The U.S. Adopted Names Council, composed of representatives from the Food and Drug Administration, American Medical Association, U.S. Pharmacopeia and American Pharmacists Association, works with the World Health Organization to assign international nonproprietary names, or INNs, to drug compounds. Similar organizations exist internationally.

A globally recognized naming process makes an otherwise confusing name game more manageable. It helps the medical community easily learn and categorize newly approved medications and reduce prescribing errors by providing a unique, standard name that reflects each active ingredient in the drug.

For example, several Type 2 diabetes medications fall under one class called glucagon-like peptide-1 (GLP-1) receptor agonists. Although all medications in this class have different brand names, each of the generic versions ends in the suffix “-tide.” This helps health providers identify all the drugs that belong to this medication class. A few examples include Byetta (exenatide), Trulicity (dulaglutide) and Victoza (liraglutide).

How are generic drug names assigned?

The naming process starts when a drug company submits an application to the U.S. Adopted Names Council with a proposed generic name. USAN considers a number of factors when evaluating a name, such as whether it relates to how the drug works, how translatable it is to other languages and whether it is easy to say. In general, the name should be simple – fewer than four syllables long – and should not be easily confused with other existing generic drugs.

Once a name is agreed upon by USAN and the drug company, it is then proposed to the INN Expert Group. Sponsored by the World Health Organization, the INN Expert Group is composed of global specialists who represent the pharmaceutical, chemical, pharmacological and biochemical sciences. They may either accept the proposed name or suggest an alternative. Once the drug company, USAN and the INN Expert Group come to an agreement about a name, it is placed in the WHO Drug Information journal for four months for public comments or objections before final adoption.

What’s in a generic drug name?

Generic names follow a prefix-infix-stem system. The prefix helps distinguish a drug from other drugs in the same class. The infix, used more occasionally, further subclassifies the drug. The stem at the very end of the name indicates the drug’s function and marks its place within the name game.

Stems are composed of one or two syllables that describe a drug’s biological effects as well as its physical and chemical qualities and structure. Drugs with the same stem share features like the conditions they treat and how they work in the body. The WHO publishes a regularly updated stem book to keep everything in line.

For example, the stem “-prazole” indicates that the drug is chemically related to a class of compounds called benzimidazoles that have similar functions. As a result, drugs such as lansoprazole (Prevacid), esomeprazole (Nexium) and omeprazole (Prilosec) all treat acid reflux, ulcers and heartburn. The “e” prefix of esomeprazole differentiates it from omeprazole, which has a slightly different chemical structure.

Another common example is drugs that use the stem “stat,” which means enzyme inhibitors. Atorvastatin (Lipitor), rosuvastatin (Crestor) and simvastatin (Zocor) all belong to the same class of inhibitors that block a key enzyme in the body’s cholesterol production process. As a result, these cholesterol-reducing “statins” are used to prevent cardiovascular conditions like heart attack and stroke.

Are there exceptions to the name game?

Although generic names stay consistent, there have been multiple changes to brand names over the past couple of decades after increases in prescribing and dispensing errors. Some examples include the acid reflux and stomach ulcer drug omeprazole, which was rebranded from Losec to Prilosec because it was frequently confused with the diuretic Lasix. Another example is when the antidepressant Brintellix was changed to Trintellix because it was commonly confused with the blood thinner Brilinta.

Some generic medications may work at multiple targets in the body and be used for multiple conditions. For example, drugs with the stem “-afil,” such as tadalafil (Cialis), sidenafil (Viagra) and vardenafil (Levitra), belong to a class of drugs that relax smooth muscle and widen the blood vessels. Although commonly prescribed for erectile dysfunction, they can also be used to treat pulmonary arterial hypertension, a specific type of elevated blood pressure that affects the arteries in the heart and lungs.

In addition, nomenclature guidelines aren’t set in stone, and the U.S. Adopted Names Council anticipates that they will continue to change as newer, more complex substances are discovered, developed and marketed.

For example, a rise in the number of drugs developed with different salts and esters has led to the use of a modified naming process to incorporate the inactive parts of the compound.

As you can guess, it takes health care providers countless months and years to learn and understand this naming process. We are taught the science behind each chemical structure and how it works, which makes it easier to know the rules of the name game. But for those without a background in chemistry and biology, it can be like reading a foreign language.

There are several resources that can help you navigate the drug name game, however. Ask your health care provider or pharmacist if you have questions about how your medication works or what it is used for. They are generally a phone call or visit away.

Jasmine Cutler does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.