CLINICAL PHARMACOLOGY 2003 (PART 8)

In any science there are two basic requirements — classification and nomenclature (names): • Classification: drugs cannot be classified and named according to a single rational system because the requirements of chemists, pharmacologists, and doctors differ. • Nomenclature: nor is it practicable always to present each drug under a single name because the formulations in which they are presented as prescribable medicines may vary widely and commercial considerations are too often paramount. Generic (nonproprietary) names should be used as far as possible when prescribing except where pharmaceutical bioavailability differences have overriding importance. ...
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CLINICAL PHARMACOLOGY 2003 (PART 8) 6 Classification and naming of drugs SYNOPSIS Drugs may be classified by: In any science there are two basic • Body system, e.g. alimentary, cardiovascular requirements — classification and • Therapeutic use, e.g. receptor blockers, enzyme nomenclature (names): inhibitors, carrier molecules, ion channels • Mode or site of action • Classification: drugs cannot be classified and — molecular interaction, e.g. glucoside, alkaloid, named according to a single rational system steroid. because the requirements of chemists, — cellular site, e.g. loop diuretic, catecholamine pharmacologists, and doctors differ. uptake inhibitor (imipramine) • Nomenclature: nor is it practicable always to • Molecular structure, e.g. glycoside, alkaloid, present each drug under a single name steroid.1 because the formulations in which they are presented as prescribable medicines may vary widely and commercial considerations are too often paramount. Nomenclature (names) Generic (nonproprietary) names should be used as far as possible when prescribing except Any drug may have names in all three of the where pharmaceutical bioavailability differences following classes: have overriding importance. 1. The full chemical name 2. A nonproprietary (official, approved, generic) name used in pharmacopoeias and chosen by official bodies; the World Health Organization (WHO) chooses recommended InternationalClassification Nonproprietary Names (rINN). The harmonisation of names began 50 years ago, andIt is evident from the way this book is organised 1that there is no homogeneous system for classifying The ATC Classification System developed by the Nordicdrugs that suits the purpose of every user. Drugs countries and widely used in Europe meets most classification requirements. Drugs are classified according toare commonly categorised according to the con- their Anatomical, Therapeutic and Chemical characteristicsvenience of who is discussing them: clinicians, into five levels of specificity, the fifth being that for the singlepharmacologists or medicinal chemists. chemical substance. 83 6 CLASSIFICATION AND NAMING OF DRUGS most countries have used rINNs for many years. from confusion with existing names, both The USA is an exception, but even here most nonproprietary and proprietary, and the USA National Names are the same as their rINN desirability of indicating relationships between counterparts. In the UK, the British Approved similar substances.3 Name (BAN) system is being progressively The generic names diazepam, nitrazepam, flur- modified such that the rINN name is adopted; in azepam are all of benzodiazepines. Their pro- many cases this involves only a trivial change. prietary names are Valium, Mogadon and Dalmane In a few cases, there is cause for concern that respectively. Names ending in -olol are adrenoceptor change of name could lead to confusion and blockers; in -pril are ACE-inhibitors; in -floxacin are constitute a public health risk, e.g. adrenaline is quinolone antimicrobials. the BAN, epinephrine is the rINN name. In such Any pharmaceutical company may manufacture instances, both rINN and BAN must currently a drug that has a well-established use and is no appear in the manufacturers literature. In ...