Drug name stems

Stems and what they mean

• -alolBeta blockers

  the WHO stem for beta blockers whose structure is related to the -olols; USAN uses it for combined alpha and beta blockers.

  • Labetalol

  Sources: [1]

• -apineAtypical antipsychotics

  a WHO stem (see -pine) for tricyclic compounds; clozapine is listed with other psychoactive -apine drugs such as olanzapine and quetiapine.

  • Clozapine
  • Quetiapine

  Sources: [1]

• -aroneAntiarrhythmics

  the WHO (USAN) stem for antiarrhythmics of this type, such as amiodarone and dronedarone.

  • Amiodarone

  Sources: [1]

• -azepamBenzodiazepines

  the WHO stem for diazepam derivatives.

  • Lorazepam

  Sources: [1]

• cef-Cephalosporins

  the WHO stem for cephalosporin antibiotics (cefalosporanic acid derivatives).

  • Ceftriaxone

  Sources: [1]

• -ciclovirHerpes antivirals (nucleoside analogues)

  the WHO stem for antivirals that are bicyclic heterocycle compounds, within the -vir group.

  • Acyclovir

  Sources: [1]

• -cillinPenicillins

  the WHO stem for antibiotics derived from 6-aminopenicillanic acid (penicillins).

  • Amoxicillin

  Sources: [1]

• -conazoleAntifungals (azoles)

  the WHO stem for systemic antifungal agents derived from miconazole.

  • Fluconazole

  Sources: [1]

• -cyclineTetracyclines

  the WHO stem for antibiotics that inhibit protein synthesis, tetracycline derivatives.

  • Doxycycline

  Sources: [1]

• -dipineCalcium channel blockers

  the WHO stem for nifedipine-type (dihydropyridine) calcium channel blockers.

  • Amlodipine

  Sources: [1]

• -dopaAntiparkinson agents (dopaminergic)

  the WHO stem for dopamine receptor agonists and dopamine derivatives used as antiparkinsonism or prolactin inhibitors; both levodopa and carbidopa carry it.

  • Carbidopa-levodopa

  Sources: [1]

• -dralazineDirect vasodilators

  the WHO stem for antihypertensives that are hydrazinephthalazine derivatives.

  • Hydralazine

  Sources: [1]

• -dronic acidBisphosphonates

  the WHO stem for bisphosphonates, which act on calcium metabolism; alendronate is the sodium salt of alendronic acid.

  • Alendronate

  Sources: [1]

• -forminBiguanides

  the WHO stem for antihyperglycemics derived from phenformin (biguanides).

  • Metformin

  Sources: [1]

• -frineAdrenergic agonists (sympathomimetics)

  the WHO stem for phenethyl-derived sympathomimetics, such as phenylephrine.

  • Norepinephrine

  Sources: [1]

• gabGabapentinoids

  the WHO stem for gabamimetic agents.

  • Gabapentin

  Sources: [1]

• -gestr- and estrHormonal contraceptives

  WHO stems for progestins and estrogens.

  • Levonorgestrel-ethinyl estradiol

  Sources: [1][2]

• gli-Sulfonylureas

  the WHO stem for antihyperglycaemics, used for sulfonylureas such as glipizide.

  • Glipizide

  Sources: [1]

• -gliflozinSGLT2 inhibitors

  the WHO stem for sodium glucose co-transporter inhibitors, a subgroup of the gli- antihyperglycaemics.

  • Empagliflozin

  Sources: [1]

• -glutideGLP-1 receptor agonists

  the WHO stem for glucagon-like peptide (GLP) analogues.

  • Semaglutide

  Sources: [1]

• -grelP2Y12 inhibitors (antiplatelets)

  the WHO stem for platelet aggregation inhibitors.

  • Clopidogrel

  Sources: [1]

• -lukastLeukotriene receptor antagonists

  the WHO stem for leukotriene receptor antagonists (a subgroup of the -ast antiasthmatic stem).

  • Montelukast

  Sources: [1]

• -micinAminoglycosides

  the WHO stem for aminoglycosides obtained from Micromonospora, the source of gentamicin.

  • Gentamicin

  Sources: [1]

• -mycinMacrolides, Glycopeptide antibiotics

  the WHO stem for antibiotics produced by Streptomyces strains; azithromycin is an erythromycin-derived macrolide.

  • Azithromycin
  • Vancomycin

  Sources: [1]

• nal-Opioid antagonists

  the WHO stem for opioid receptor antagonists and agonists related to normorphine.

  • Naloxone

  Sources: [1]

• -nidazoleAntiprotozoals and anaerobic antibiotics (nitroimidazoles)

  the WHO stem for antiprotozoals and radiosensitizers related to metronidazole.

  • Metronidazole

  Sources: [1]

• nifur-Urinary tract antibacterials

  the WHO stem for 5-nitrofuran derivatives.

  • Nitrofurantoin

  Sources: [1]

• -ololBeta blockers

  the WHO stem for beta-adrenoreceptor antagonists.

  • Metoprolol

  Sources: [1]

• -onidineCentral alpha-2 agonists

  the WHO stem for antihypertensives that are clonidine derivatives.

  • Clonidine

  Sources: [1]

• -orphineOpioid partial agonists

  the WHO stem for morphinan opioid receptor agonists and antagonists.

  • Buprenorphine-naloxone

  Sources: [1][2]

• -orphoneOpioid agonists

  listed by WHO among the morphine-derived opioid names (with oxymorphone); related to the -orphine stem.

  • Hydromorphone

  Sources: [1]

• -oxacinFluoroquinolones

  the WHO stem for quinolone antibacterials related to nalidixic acid.

  • Ciprofloxacin

  Sources: [1]

• -parinHeparins

  the WHO stem for heparin derivatives, including low molecular weight heparins.

  • Enoxaparin
  • Heparin (unfractionated)

  Sources: [1]

• -peridolTypical antipsychotics (first-generation)

  the WHO stem for antipsychotics that are haloperidol derivatives.

  • Haloperidol

  Sources: [1]

• -prazoleProton pump inhibitors

  the WHO stem for antiulcer benzimidazole derivatives (proton pump inhibitors).

  • Omeprazole

  Sources: [1]

• predCorticosteroids

  the WHO stem for prednisone and prednisolone derivatives.

  • Prednisone

  Sources: [1]

• -prilACE inhibitors

  the WHO stem for angiotensin-converting enzyme inhibitors.

  • Lisinopril

  Sources: [1]

• -profenNonsteroidal anti-inflammatory drugs (NSAIDs)

  the WHO stem for anti-inflammatory agents that are ibuprofen derivatives.

  • Ibuprofen

  Sources: [1]

• -relin, sub-stem -morelinGrowth hormone secretagogues (GHRH analogs and ghrelin receptor agonists)

  the WHO stem for growth hormone release-stimulating peptides.

  • Tesamorelin

  Sources: [1]

• -renoneAldosterone antagonists (potassium-sparing diuretics)

  the WHO stem for spironolactone-type aldosterone antagonists, such as eplerenone.

  • Spironolactone

  Sources: [1]

• -salNonsteroidal anti-inflammatory drugs (NSAIDs)

  the WHO stem for salicylic acid derivatives.

  • Aspirin

  Sources: [1]

• -sartanAngiotensin II receptor blockers (ARBs)

  the WHO stem for angiotensin II receptor antagonists.

  • Losartan

  Sources: [1]

• -semideLoop diuretics

  the WHO stem for diuretics derived from furosemide, which is the parent compound.

  • Furosemide

  Sources: [1]

• -setron5-HT3 receptor antagonists

  the WHO stem for serotonin 5-HT3 receptor antagonists.

  • Ondansetron

  Sources: [1]

• sulfa-Sulfonamide antibiotics (sulfa drugs)

  sulfa- marks sulfonamide anti-infectives (sulfamethoxazole), and -prim marks antibacterial dihydrofolate reductase inhibitors, trimethoprim derivatives.

  • Trimethoprim-sulfamethoxazole

  Sources: [1][2]

• -teplaseThrombolytics (fibrinolytics)

  the WHO stem for tissue-type plasminogen activators, part of the -ase enzyme group.

  • Alteplase

  Sources: [1]

• -terolShort-acting beta-2 agonists

  the WHO stem for phenethylamine bronchodilators.

  • Albuterol

  Sources: [1]

• -tiazemCalcium channel blockers

  the WHO stem for calcium channel blockers derived from diltiazem, the parent compound.

  • Diltiazem

  Sources: [1]

• -tideMelanocortin receptor agonists, Mitochondria-targeted peptides, Dual and triple incretin agonists (GIP/GLP-1 and GIP/GLP-1/glucagon)

  the WHO stem for peptides and glycopeptides.

  • Afamelanotide
  • Elamipretide
  • Tirzepatide

  Sources: [1]

• -tizideThiazide diuretics

  the WHO stem for chlorothiazide-derived diuretics.

  • Hydrochlorothiazide

  Sources: [1]

• -tocinOxytocics (uterine stimulants)

  the WHO stem for oxytocin derivatives.

  • Oxytocin

  Sources: [1]

• -toinAntiepileptics (anticonvulsants)

  the WHO stem for hydantoin-derivative antiepileptics.

  • Phenytoin

  Sources: [1]

• -tralineSelective serotonin reuptake inhibitors (SSRIs)

  the WHO stem for serotonin reuptake inhibitors in this structural family.

  • Sertraline

  Sources: [1]

• -trexateAntimetabolites (folic acid antagonists)

  the WHO stem for folic acid analogues (antimetabolites).

  • Methotrexate

  Sources: [1]

• -triptylineTricyclic antidepressants (TCAs)

  the WHO stem for antidepressants that are dibenzo[a,d]cycloheptane or cycloheptene derivatives.

  • Amitriptyline

  Sources: [1]

• tropAnticholinergics (antimuscarinics)

  the WHO stem for atropine derivatives.

  • Atropine

  Sources: [1]

• -vastatinStatins (HMG-CoA reductase inhibitors)

  the WHO stem for HMG-CoA reductase inhibitors, usually taught as -statin.

  • Atorvastatin

  Sources: [1]

• -xabanDirect factor Xa inhibitors

  the WHO stem for blood coagulation factor Xa inhibitors.

  • Apixaban

  Sources: [1]

• -zepine (see -pine)Antiepileptics (anticonvulsants)

  the WHO stem for tricyclic compounds.

  • Carbamazepine

  Sources: [1]

Named outside the stem system

These names come from a natural substance, an element or salt, or the molecule itself.

• AcetaminophenAnalgesics and antipyretics (non-opioid)

  No WHO naming stem. Acetaminophen (international name paracetamol) is named outside the stem system.

  Sources: [1]

• AdenosineAntiarrhythmics

  No WHO naming stem. Adenosine is a nucleoside found naturally in every cell of the body; the related -denoson stem names synthetic adenosine A receptor agonists such as regadenoson.

  Sources: [1][2]

• AllopurinolAntigout agents (xanthine oxidase inhibitors)

  No WHO naming stem. Allopurinol is a structural analogue of hypoxanthine, a natural purine, and its name is not built from a stem.

  Sources: [1]

• Calcium gluconateCalcium salts

  No WHO naming stem. Calcium gluconate is a mineral salt, the calcium salt of gluconic acid, not a nonproprietary drug name built from a stem.

  Sources: [1]

• DigoxinCardiac glycosides

  No WHO naming stem. Digoxin is a cardiac glycoside named for its source, the foxglove plant (Digitalis).

  Sources: [1]

• DonepezilCholinesterase inhibitors

  No WHO naming stem. Donepezil is not listed under a stem in the WHO stem book.

  Sources: [1]

• EpinephrineAdrenergic agonists (sympathomimetics)

  No WHO naming stem. Epinephrine (adrenaline) is the natural hormone; the -drine stem for sympathomimetics, as in ephedrine, does not apply to its name.

  Sources: [1]

• FluticasoneInhaled corticosteroids

  No dedicated stem. WHO lists fluticasone with the corticosteroids named outside the -pred- and -olone groups; the -casone ending is shared with cloticasone.

  Sources: [1]

• GlucagonAntihypoglycemics

  No WHO naming stem. Glucagon is the name of the natural pancreatic hormone; the -glutide stem covers glucagon-like peptide (GLP) analogues, not glucagon itself.

  Sources: [1]

• Insulin glargineLong-acting insulins

  No WHO naming stem. Insulin analogs are named as insulin plus a distinguishing word (glargine) rather than by stem.

  Sources: [1]

• Insulin lisproRapid-acting insulins

  No WHO naming stem. Insulin analogs are named as insulin plus a distinguishing word (lispro) rather than by stem.

  Sources: [1]

• Insulin NPH (isophane)Intermediate-acting insulins

  No WHO naming stem. NPH (isophane) insulin is human insulin crystallized with protamine and is named by type rather than by stem.

  Sources: [1]

• Insulin regular (human)Short-acting insulins

  No WHO naming stem. Regular insulin is identical to human insulin and is named by type rather than by stem.

  Sources: [1]

• IsoniazidAntituberculosis drugs

  No WHO naming stem. Isoniazid (isonicotinic acid hydrazide) is not built from a stem on the WHO stem list.

  Sources: [1]

• LevothyroxineThyroid hormones

  No WHO naming stem. The name describes the molecule: the levo (L) isomer of thyroxine (T4).

  Sources: [1]

• LithiumMood stabilizers

  No WHO naming stem. Lithium is an element, given as the lithium carbonate salt.

  Sources: [1]

• Magnesium sulfateMagnesium salts

  No WHO naming stem. Magnesium sulfate is an inorganic salt, not a nonproprietary drug name built from a stem.

  Sources: [1]

• MethimazoleAntithyroid drugs (thionamides)

  No WHO naming stem. Methimazole (INN thiamazole) is named for its chemistry, a methyl imidazole thiol, rather than from a stem.

  Sources: [1][2]

• MethylphenidateCNS stimulants

  No WHO naming stem. Methylphenidate is not listed under a stem in the WHO stem book.

  Sources: [1]

• MorphineOpioid agonists

  No stem in its own name. Morphine is the parent compound for the WHO -orphine stem used for morphine-derived opioids, such as buprenorphine.

  Sources: [1]

• NitroglycerinNitrates

  No WHO stem applies. Nitroglycerin (international name glyceryl trinitrate) is an organic nitrate named outside the stem system; the nitro- prefix only marks NO2 derivatives.

  Sources: [1]

• Phytonadione (vitamin K)Vitamin K replacements

  No WHO naming stem. Phytonadione is the nonproprietary name for vitamin K1, which the stem book places in its vitamins group rather than naming with a stem.

  Sources: [1]

• Potassium chloridePotassium supplements

  No WHO naming stem. Potassium chloride is an inorganic salt (KCl), not a nonproprietary drug name built from a stem.

  Sources: [1]

• Valproic acidAntiepileptics (anticonvulsants)

  No WHO naming stem. Valproic acid (2-propylpentanoic acid) is named outside the stem system.

  Sources: [1]

• WarfarinVitamin K antagonists

  No stem in its own name. The WHO stem book lists warfarin with the coumarin anticoagulants related to the -arol group (dicoumarol type).

  Sources: [1]

More study lists

• High-alert medications
• Narrow therapeutic index drugs
• Antidotes and reversal agents
• Boxed warnings