Another great way of understanding medications is to know the common drug stems. Usually, drugs of the same therapeutic class are given names with the same stem. These stems are mostly placed word-finally, but in some cases word-initial stems are also used.

Stems are useful by making communication of drugs more precise to avoid prescribing errors. Having unambiguous standard of names for each drug is important because a drug may be sold by many different brand names, or a branded medication may contain more than one drug.

The hyphens indicate the position of the stem, prefix, infix or suffix, within the INN. In the event that the hyphen is absent, the stem may be used in any position within the name.

Below is a cheat sheet table that has three columns: Drug Stem, Drug Class, and an Example. Each stem has hyphens at one or both ends of its text to show that it is found at the beginning, end, or in the middle of the generic name.


Using the link below, you can download the PDF file of the cheat sheet. You can print it by using a Letter size paper.

Common Drug Stems Cheat Sheet

Drug Stem Drug Class and/or Stem Explanation Examples
–alol Combined alpha and beta blockers labetalol, medroxalol
–andr– Androgens nandrolone
–anserin Serotonin 5–HT(sub)2 receptor antagonists altanserin, tropanserin, altanserin
–arabine Antineoplastics (arabinofuranosyl derivatives) fludarabine
–ase Enzymes alglucerase, dornase alfa
–azepam Antianxiety agents (diazepam type) lorazepam
–azosin Antihypertensives (prazosin type) doxazosin
–bactam Beta–lactamase inhibitors sulbactam
–bamate Tranquilizers/antiepileptics meprobamate, felbamate
–barb Barbituric acid derivatives phenobarbital
–butazone Anti–inflammatory analgesics (phenylbutazone type) mofebutazone
–caine Local anesthetics dibucaine
cef– Cephalosporins cefazolin
–cillin Penicillins ampicillin
–conazole Antifungals (miconazole type) fluconazole, oxiconazole
–cort– Cortisone derivatives hydrocortisone
–curium Neuromuscular blocking agents atracurium
–cycline Antibiotics (tetracycline type) minocycline
–dralazine Antihypertensives (hydrazine–phthalazines) hydralazine
–erg– Ergot alkaloid derivatives pergolide
estr– Estrogens estrone
–fibrate Antihyperlipidemics bezafibrate
–flurane Inhalation anesthetics enflurane, isoflurane
–gest– Progestins megestrol
–irudin Anticoagulants desirudin
–leukin Interleukin–2 derivatives teceleukin, aldesleukin
–lukast Leukotriene antagonists montelukast, zafirlukast
–mab Monoclonal antibodies capromab, daclizumab, detumomab,
–mantadine Antivirals rimantadine
–monam Monobactam antibiotics gloximonam
–mustine Antineoplastics carmustine
–mycin Antibiotics (streptomyces strains) lincomycin
–olol Beta–blockers (propranolol type) timolol, atenolol
–olone Steroids (no prednisone derivatives) minaxolone
–oxacin Antibiotics (quinolone derivatives) difloxacin, ciprofloxacin
–pamide Diuretics (sulfamoylbenzoic acid derivatives) adipamide
–pamil Coronary vasodilators tiapamil
–parin Heparin derivatives and low molecular weight (or depolymerized) heparins heparin, tinzaparin, dalteparin
–peridol Antipsychotics (haloperidol type) haloperidol
–poetin Erythropoietins epoetin alfa, epoetin beta
–pramine Antidepressants (imipramine type) lofepramine
–pred Prednisone derivatives prednicarbate, cloprednol
–pril Antihypertensives (ACE inhibitors) enalapril, temocapril, spirapril
–profen Anti–inflammatory/analgesic agents (ibuprofen type) flurbiprofen
–rubicin Antineoplastic antibiotics (daunorubicin type) epirubicin, idarubicin
–sartan Angiotensin II receptor antagonists losartan, eprosartan
–sulfa Antibiotics (sulfonamide derivatives) sulfasalazine
–thiazide Diuretics (thiazide derivatives) chlorothiazide
–tocin Oxytocin derivatives oxytocin, pitocin
–trexate Antimetabolites (folic acid derivatives) methotrexate
–triptyline Antidepressants amitriptyline
-uracil Uracil derivatives used as thyroid antagonists and as antineoplastics fluorouracil
–vastatin Antihyperlipidemics (HMG–CoA inhibitors) lovastatin, simvastatin
vir-, -vir- or -vir Antiviral substances (undefined group) viroxime, envirodyne, ganciclovir

See Also