Generic names and brand names | Medications

Any FDA-approved drug has a generic name and a brand name. The United States Adopted Names (USAN) Council gives the generic name of a drug. The generic name is to “chemical name”, as the brand name is to “trade Name”.

Generic name: The generic name consists of a stem and, sometimes, a substem that appears at the end of the name. Stems denote the chemical structure, indication, or action at a specific receptor. Drugs with the same stem are related. It also has a one or two-syllable prefix that differentiates each drug from others in its class.

For example, “sildenafil” and “tadalafil” have a stem “-afil” as they belong to the same class of medications called PDE5 (phosphodiesterase 5) inhibitors. The prefixes are “sil” and “tadal”. The “den” in sildenafil is known as an infix and may be used to classify certain medications further.

Brand name: A specific name given by a drug company or manufacturer protected by a patent.

For example, “Tylenol” is the brand name for “acetaminophen”.

Examples of brand names and generic names of common drugs

Brand name	Generic name
Protonix	Pantoprazole
Benadryl	Diphenhydramine
Tums	Calcium carbonate
Nasonex	Mometasone
Allegra	Fexofenadine
Ventolin	Albuterol

A generic medication may be sold under its generic or brand name. For example, Ibuprofen (generic) is sold under various brand names, such as Advil and Motrin.

Sidenote

Bioequivalence:

Generic versions of brand name drugs must be bioequivalent to the original drug. The two drugs should release the active ingredient into the bloodstream at the same amount, at the same rate, and have the same quality

Common drug name stems

Stem	Drug class or classification	Example
-stat	Anti-hyperlipidemics or HMG CoA reductase inhibitors	Atorvastatin
-prazole	Proton pump inhibitors or PPI for acid reflux/GERD	Omeprazole
-lukast	Leukotriene receptor blockers	Montelukast
-grel	Platelet aggregation inhibitors	Clopidogrel
-faxine	Antidepressants; serotonin and norepinephrine reuptake inhibitors (SNRI)	Venlafaxine
-oxetine	Antidepressants; selective serotonin reuptake inhibitors (SSRI)	Duloxetine
-sartan	Angiotensin II receptor blockers	Valsartan
-floxacin	Antibiotics; quinolone derivatives	Levofloxacin
-vir	Antivirals (avir, ovir, ivir)	Valacyclovir
-mab	Monoclonal antibodies	Daclizumab
-alol	Combined alpha and beta blockers	Labetalol
-ilol	Combined alpha and beta blockers	Carvedilol
-olol	Beta blockers	Metoprolol
-olone	Non-prednisone steroids	Minaxolone
-cillin	Penicillins	Penicillin
-ase	Enzymes	Dornase alfa
-caine	Local anesthetics	Lidocaine, bupivacaine, prilocaine
-conazole	Azole antifungals	Fluconazole

Commonly used drug prefixes

Prefix and meaning	Example
Cef- (related to cephalosporins)	Cefazolin
Ceph- (related to cephalosporins)	Cephalexin
Chlor- (chlorine-containing compound)	Chlorpromazine
Flu- (fluorinated compounds)	Fluoxetine
Sulfa- (sulfonamides)	Sulfamethoxazole, sulfasalazine
Thio- (Sulfur-containing compounds)	Thiopental
Meth- (methylated compounds)	Methotrexate
Pred- (type of corticosteroid)	Prednisone, prednisolone

Prefix “Peg” means that a biologic substance, such as peptide, is pegylated. Infix -io- is added to suggest a high iodine content (e.g. amiodarone). When -fos- appears anywhere in a drug name, the element phosphorus is present (e.g. ifosfamide).

Sidenote

Therapeutic equivalence:

Therapeutic equivalence = Bioequivalence + Pharmaceutical equivalence*
Therapeutically equivalent drugs are expected to have the same clinical effect and safety profile and contain identical amounts of the identical active drug ingredient in the identical dosage form and route of administration.
Therapeutically equivalent drugs can be substituted for each other.
Therapeutically equivalent drugs can still differ in shape, color, flavor, inactive ingredients etc.

*Pharmaceutical equivalence means drugs with identical active ingredients in identical amounts (strength), forms, and routes of administration.

Orange book: Also known as the Approved Drug Products with Therapeutic Equivalence Evaluations, the Orange Book is published by the FDA and lists all FDA approved drugs on the basis of safety and efficacy. The FDA maintains an online Orange Book database which makes it easy to search approved drugs using various identifiers like active ingredient, name and patent number. The Orange Book contains a coding system to denote therapeutic equivalence. “A” codes contain products that are considered therapeutically equivalent to other pharmaceutically equivalent products, while “B” codes contain products that require further investigation and review to determine therapeutic equivalence.