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Guidelines on the Use of International Nonproprietary Names (INNs) for Pharmaceutical Substances
(1997; 41 pages) View the PDF document
Table of Contents
Open this folder and view contents1. General introduction
Open this folder and view contents2. Elements in the INN system
Open this folder and view contents3. Principles for selection of INNs
View the document4. Protection of INNs
Open this folder and view contents5. How to apply for an INN
View the document6. References for supporting material
View the documentAnnex 1: Background information on the INN programme
View the documentAnnex 2: General principles for guidance in devising international nonproprietary names for pharmaceutical substances
View the documentAnnex 3: List of common stems used in the selection of INNs
View the documentAnnex 4: Specific groups of biological compounds
View the documentAnnex 5: WHA46.19 - Nonproprietary names for pharmaceutical substances
View the documentAnnex 6: Procedure for the selection of international nonproprietary names for pharmaceutical substances
View the documentAnnex 7: Applications for INNs through national authorities (addresses)
View the documentAnnex 8: INN request form

Annex 3: List of common stems used in the selection of INNs




substem, if available


anti-inflammatory agents, ibufenac derivatives


synthetic polypeptides with a corticotropin-like action

-adol or -adol-



analgesics, tifluadom derivatives


antiarrhythmics, propafenone derivatives


antiarrhythmics, ajmaline derivatives


antacids, aluminium salts


antacids, aluminium derivatives


see vir

andr or -stan- or -ster-

steroids, androgens


serotonin receptor antagonists (mostly 5-HT2)


anthelminthics (undefined group)


see -pine


arabinofuranosyl derivatives


antiarthritic substances, acting like clobuzarit and lobenzarit (mechanism different from anti-inflammatory type substances, e.g. -fenamates or -profens)


anticoagulants, dicoumarol derivatives


antimalarial agents, artemisinin related compounds




-dismase (superoxide dismutase activity),


-pase (lipase)


-teplase (tissue plasminogen activators),


-uplase (urokinase-type-plasminogen activators)


antiasthmatic, antiallergics, not acting primarily as antihistaminics;


-lukast (leukotriene receptor antagonist);


-trodast (thromboxane A2 receptor antagonists, antiasthmatics)




benzodiazepine receptor antagonists/agonists (benzodiazepine derivatives)


diazepam derivatives


cholecystokinin receptor antagonist


narcotic antagonists/agonsists related to 6,7-benzomorphan


antihistaminics or local vasoconstrictors, antazoline derivatives


antihypertensive substances, prazosin derivatives


b-lactamase inhibitors


tranquillizers, propanediol and pentanediol derivatives


hypnotics, barbituric acid derivatives


anthelminthics, tiabendazole derivatives


anabolic steroids


bradycardic agents


anti-inflammatory analgesics, phenylbutazone derivatives


Class I antiarrhythmics, procainamide and lidocaine derivatives (antifibrillants with local anaesthetic activity)


local anaesthetics


Vitamin D analogues/derivatives


antibiotics, carbacepham derivatives


benzodiazepine receptor antagonists/agonists (carboline derivatives)


see vir


antibiotics, cefalosporanic acid derivatives

cell- or cel- or -cell-

cellulose derivatives


cell-ate (cellulose ester derivatives);


-cellose (cellulose ether derivatives)


hepatoprotective substances with a carboxylic acid group


naturally occurring antibiotics (undefined group)


antibiotics, 6-aminopenicillanic acid derivatives


nucleoside antiviral or antineoplastic agents, cytarabine or azarabine derivatives


hypnotic tranquillizers


blood coagulation factors;


(-)eptacog (blood coagulation VII);


(-)octocog (blood coagulation factor VIII);


(-)nonacog (blood coagulation factor IX)


systemic antifungal agents, miconazole derivatives


corticosteroids, except prednisolone derivatives


diuretics, etacrynic acid derivatives


acetylcholinesterase inhibitors, tacrine derivatives


antiallergics, cromoglicic acid derivatives


see -ium


antibiotics, tetracycline derivatives


cardiac stimulants, pimobendan derivatives


antimycobacterials, diaminodiphenylsulfone derivatives


see -ermin




calcium channel blockers, nifedipine derivatives


see -ase


dopamine receptor agonists, dopamine derivatives, used as antiparkinsonism/prolactin inhibitors;


antibacterials, quinoline dioxide derivatives


antihypertensives, hydrazinephthalazine derivatives




-frine: sympathomimetic, phenethyl derivatives

-dronic acid

calcium metabolism regulator, pharmaceutical aid


antiparasitics, ivermectin derivatives


endothelin receptor antagonists


see -cog


ergot alkaloid derivatives


analgesics, pethidine derivatives


growth factors;


-dermin (epidermal growth factors);


-fermin (fibrinoblast growth factors);


-nermin (tumour necrosis factor);


-sermin (insulin-like growth factors)




diuretics, piretanide derivatives


see -kin


mucolytic, bromhexine derivatives

-fenamic acid

anti-inflammatory, anthranilic acid derivatives


-fenamate (“-fenamic acid” derivatives)


diagnostic aids; (phenylcarbamoyl)methyl iminodiacetic acid derivatives


analgesics, glafenine derivatives - (subgroup of fenamic acid group)


narcotic analgesics, fentanil derivatives


see -ermin


fibrinogen receptor antagonists (glycoprotein Iib/IIIa receptor antagonists)


clofibrate derivatives


5-lipoxygenase-activating protein (FLAP) inhibitor


general inhalation anaesthetics, halogenated alkane derivatives


antihyperglycaemics, phenformin derivatives

-fos (-vos)

insecticides, anthelmintics, pesticides etc., phosphorous derivatives

-fos- or fos-

various pharmacological categories belonging to -fos (other than above)


calcium channel blockers acting as vasodilators


see -drine


antifungal antibiotics


N-methylated xanthine derivatives


gabamimetic agents


diagnostic agents, gadolinium derivatives


thrombin inhibitor, antithrombotic agents


steroids, progestogens


MAO-inhibitors type B


antibiotics produced by Aspergillus strains


antihyperglycaemics, sulfonamide derivatives


dopamine receptor agonists, ergoline derivatives


see -stim


see -stim

-grel- or -grel

platelet aggregation inhibitors


antihypertensives, guanidine derivatives


anti-inflammatory, isoxicam derivatives


antiestrogens, clomifene and tamoxifen derivatives


Class III antiarrhythmics, sematilide derivatives




immunomodulators, both stimulant/suppressive and stimulant


immunosuppressants (other than antineoplastics)


iodine-containing contrast media

-io- or iod-

iodine containing compounds other than contrast media


serotonin (5HT1) receptor agonists, sumatriptan derivatives


hirudin derivatives


antiarrhythmics, disopyramide derivatives


quarternary ammonium compounds;


-curium (curare-like substances)


diphenylmethyl piperazine derivatives;


-rizine (antihistaminics/cerebral (or peripheral) vasodilators)


antibiotics, kanamycin and bekanamycin derivatives (obtained from Streptomyces kanamyceticus);


potassium channel blockers


potassium channel activators, antihypertensive


enkephalin agonists


interleukin type substances;


-nakin (Il-1 derivatives)


-leukin (Il-2 derivatives)


-plestim (Il-3 derivatives)


-exakin (Il-6 derivatives)


interleukin receptor antagonists;


-nakinra (Il-1 receptor antagonists)


renin inhibitors


see -kin


see -stat


see -ast


monoclonal antibodies (for details please see page .....)


adamantane derivatives;


-mantine, -mantone


cholinergic agents, arecoline derivatives




sigma receptor ligands


aromatase inhibitors


anti-inflammatory, indometacin derivatives


antibiotics obtained from various Micromonospora


monobactam antibiotics


see -relin


see -stim


antivirals, quinoline derivatives


monoamine oxidase inhibitors, hydrazine derivatives** not part of definition


antineoplastic, alkylating agents, (b-chloroethyl)amine derivatives


antibiotics, produced by Streptomyces strains


cannabinol derivatives


see -kin


see -kinra


narcotic antagonists/agonists related to normorphine


tumor necrosis factor antagonist


see -ermin


nicotinic acid or nicotinoyl alcohol derivatives


antihypercholesterolaemic and/or vasodilating nicotinic acid esters


antiprotozoals, metronidazole derivatives


5-nitrofuran derivatives


anti-inflammatory, anilinonicotinic acid derivatives


see -cog


see -cog


b-adrenoreceptor antagonists;


-alol: aromatic ring -CH-CH2-NH-R related to -olols


steroids other than prednisolone derivatives


dopaminergic agents dopamine derivatives used as cardiac stimulant/antihypertensives/diuretics


steroids for topical use, acetal derivatives


antihypertensives, clonidine derivatives




narcotic antagonists/agonists, morphinan derivates;


-orphine, -orphinol, orphone


antibacterials, nalidixic acid derivatives


benzodioxane derivatives


antiparasitics, salicylanides and analogues


antibiotics, oxacefalosporanic acid derivatives


antidepressants, fluoxetine derivatives


platelet-activating factor antagonists


diuretics, sulfamoylbenzoic acid derivatives


coronary vasodilators, verapamil derivatives


glycopeptide antibiotics


heparin derivatives including low molecular mass heparins


analogues of penicillanic acid antibiotics modified in the five-membered ring


see -perone


see -perone


tranquillizers, neuroleptics, 4'-fluoro-4-piperidinobutyrophenone derivatives;


-peridol (antipsychotics, haloperidol derivatives);


-peridone (antipsychotics, risperidone derivatives)


hypnotics/sedatives, zolpidem derivatives


tricyclic compounds;


-apine (psychoactive);


-cilpine (antiepileptic);


-dipine (see -dipine)


-zepine (antidepressant/neuroleptic);


-oxepin, -oxopine, -sopine, -tepines


psychotropics, phenylpiperazine derivatives


antimycotic pyridone derivatives


antibacterials (Actinoplanes strains)


antineoplastic agents, platinum derivatives


see -stim


pyrazolo[.]pyrimidine derivatives, used as anxiolytics, sedatives, hypnotics


-poetin erythropoietin type blood factors


-porfin benzoporphyrin derivatives


substances of the imipramine group


antiulcer, benzimidazole derivatives


prednisone and prednisolone derivatives;


-methasone or -metasone, -betasol


vasoconstrictors, vasopressin derivatives


sulpiride derivatives


angiotensin-converting enzyme inhibitors


antibacterials, trimethoprim derivatives


anti-inflammatory agents, ibuprofen derivatives




-prostil (prostaglandins, anti-ulcer)


see -prost


benzodiazepine receptor partial agonists (quinoline derivatives)


amide type nootrope agents, piracetam derivatives


prehormones or hormone-release stimulating peptides:


-morelin (growth hormone release-stimulating peptides);


-tirelin (thyrotropin releasing hormone analogues)


hormone-release inhibiting peptides


aldosterone antagonists, spironolactone derivates

-restat (or -restat-)

see -stat


retinol derivatives


ribofuranil-derivatives of the pyrazofurin type


antibiotics, rifamycin derivatives


cardiac stimulants, amrinone derivatives


see -izine


aromatase inhibitors, imidazole-triazole derivatives


antineoplastic antibiotics, daunorubicin derivatives


salicylic acid derivatives:


-sal-, salazo-, -salazine/-salazide, -salan


angiotensin II receptor antagonists, antihypertensive (non-peptidic)


diuretics, furosemide derivatives


see -ermin


derivatives of Rauwolfia alkaloids


serotonin receptor antagonists (5-HT3) not fitting into other established groups of serotonin receptor antagonists


growth hormone derivatives


anxiolytics, buspirone derivatives

-stat (or -stat-)

enzyme inhibitors:


-lipastat (pancreatic lipase inhibitors);


-restat or -restat- (aldose-reducing inhibitors);


-vastatin (antilipidemic substances, HMG CoA reductase inhibitors)


mucolytics, other than bromhexine derivatives


androgens/anabolic steroids:


-testosterone, -sterone, -ster-, -gesterone, -sterone, sterol, ster,
-(a)steride (antineoplastics)


colony stimulating factors:


-grastim (granulocyte colony stimulatory factor (G-CSF) type) substances;


-gramostim (granulocyte macrophage colony stimulating factor (GM-CSF) type substances);


-mostim (macrophage stimulating factors (M-CSF) type substances);


-plestim (interleukin-3 analogues and derivatives)


anti-infectives, sulfonamides


antineoplastic, alkylating agents, methanesulfonates


antineoplastics, topoisomerase I inhibitors


antineoplastics, thiotepa derivatives


see -ase


bronchodilators, phenethylamine derivatives [previously -prenaline or -terenol]




calcium channel blockers, diltiazem derivatives


peptides and glycopeptides (for special groups of peptides see -actide, -pressin, -relin, -tocin)


histamine H2-receptor antagonists, cimetidine derivatives


see -relin


diuretics, chlorothiazide derivatives


oxytocin derivatives


antiepileptics, hydantoin derivatives


folic acid analogues


antibiotics, polyene derivatives


antidepressants, dibenzo[a,d]cycloheptane or cyclopheptene derivatives


thromboxane A2-receptor antagonists; antithrombotic agents


see -ast


atropine derivatives


see -ase


uracil derivatives used as thyroid antagonists and as antineoplastics


uridine derivatives used as antiviral agents and as antineoplastics; also -udine


see -stat


spasmolytics with a papaverine-like action

vin- or -vin-

vinca alkaloids


antivirals (undefined group):


-amivir (neuraminidase inhibitors);


-cavir (carbocyclic nucleosides);


-virsen (antisense oligonucleotides)


see vir


antiviral; antineoplastics, zidovudine derivatives


antiallergic respiratory tract drugs, xanoxic acid derivatives


alozafone derivatives


see -pine

Explanatory note:

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.

The following common stems have been discontinued:



mer- or -mer-

mercury-containing drugs, antimicrobial or diuretic
(deleted from General Principles in List 28 prop. INN)


antineoplastics, nucleotoxic agents
(deleted from General Principles in List 24 prop. INN)


alcohols and phenols
(deleted from General Principles in 14th report)

-quine, quin

quinoline derivatives
(deleted from General Principles in List 28 prop. INN)


(deleted from General Principles in List 24 prop. INN)


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