Guide to Good Prescribing - A Practical Manual
(1994; 115 pages) [French] [Spanish] View the PDF document
Table of Contents
View the documentAcknowledgments
View the documentWhy you need this book
Open this folder and view contentsPart 1: Overview
Open this folder and view contentsPart 2: Selecting your P(ersonal) drugs
Open this folder and view contentsPart 3: Treating your patients
Close this folderPart 4: Keeping up-to-date
Close this folderChapter 12. How to keep up-to-date about drugs
View the documentMake an inventory of available sources of information
View the documentChoose between sources of information
View the documentEfficient reading
View the documentConclusion
Open this folder and view contentsAnnexes
View the documentBack Cover

Make an inventory of available sources of information

There are numerous sources of drug information, ranging from international data bases, journals and reference books, to national or regional drug information centres, and locally produced formularies and bulletins. Annex 2 provides a list of essential references. Some sources are commercial and independent, others are non-commercial. Information is available verbally or in written form, on tape or video, ‘on-line’ (interactive connection with a central computer data base) or on CD-ROM (Compact Disk Read-Only Memory, a compact disk with information, read by personal computer).

Reference books

Reference books can cover general or clinical pharmacology, or specialize in a particular aspect. Examples of general pharmacological reference books in English are Goodman and Gilman’s The Pharmacological Basis of Therpautics and Laurence and Bennett’s Clinical Pharmacology (see Annex 2). Good equivalents exist in other languages. An important criterion in choosing reference books is the frequency of new editions. Only publications that are revised every two to five years can provide up-to-date knowledge.

Martindale’s The Extra Pharmacopoeia is an excellent reference book with detailed drug information on most active substances and chemicals. However, it does not distinghuish between essential and non-essential drugs and does not contain comparative therapeutic information. Avery’s Drug Treatment is a more specialized book, appropriate for prescribers with a special interest in clinical pharmacology.

Another example of a specialized textbook is Meyler's Side Effects of Drugs, which provides an annually updated assessment of side effects of drugs reported worldwide. It is, however, expensive. Other specialized books address such areas as psychotropic drugs, or specific risk groups such as drugs in lactation, drugs for children, or drugs for the elderly.

Drug compendia

In many countries there are publications that list the drugs available on the market. These compendia vary in type and scope but usually include generic and brand names; chemical composition; clinical indications and contraindications; warnings, precautions and interactions; side effects; administration and dosage recommendations. Some are based on the official labelling information for the product as approved by the national regulatory authority. An example is the annual Physician's Desk Reference, which is available free of charge to physicians in the United States.

Commercially sponsored drug compendia may have additional limitations. For example, the drug listing may be incomplete, and comparative assessments are usually lacking. An example is the Monthly Index of Medical Specialities (MIMS) which is published in different parts of the world.

However, comprehensive and objective compendia are available which do include comparative assessments and/or provide criteria for choice within well-defined therapeutic drug categories. Examples are the United States Pharmacopeia Dispensing Information (USP DI), which is not available free of charge, and the British National Formulary (BNF), which is free to all UK prescribers. The latter includes information on cost, which is not often included in other compendia. The frequent revisions of both publications contribute to their value. In fact, they are issued so frequently that old copies, which may be available at very low cost or free of charge, remain useful for quite some time.

National lists of essential drugs and treatment guidelines

In many developing countries a national list of essential drugs exists. It usually indicates the essential drugs chosen for each level of care (dispensary, health centre, district hospital, referral hospital). It is based on a consensus on the treatment of choice for the most common diseases and complaints, and defines the range of drugs that is available to prescribers. If no national list of essential drugs exists, you may consult the WHO model list (see Annex 2). Very often national treatment guidelines, which include the most important clinical information for the prescriber (treatment of choice, recommended dosage schedule, side effects, contraindications, alternative drugs, etc.) are available. You should verify whether such guidelines exist in your country. Try to obtain the most recent edition.

Drug formularies

Formularies contain a list of pharmaceutical products, together with information on each drug. They can be national, regional or institutional. They are usually developed by therapeutic committees and they list the drugs that are approved for use in that country, region, district or hospital. In many countries drug formularies are also developed for health insurance programmes, listing the products that are reimbursed. Drug formularies are usually drug-centred. Their value is enhanced if they contain comparisons between drugs, evaluations and cost information, but that is often not the case. The excellent BNF has already been mentioned. Try to get your own copy, even if it is not the most recent one. It fits well in your pocket.

Drug bulletins

These periodicals promote rational drug therapy and appear at frequent intervals, ranging from weekly to quarterly. Independent drug bulletins, i.e. non-industry sponsored, provide impartial assessments of drugs and practical recommend-ations, based on a comparison between treatment alternatives.

Drug bulletins can be a critical source of information in helping prescribers to determine the relative merits of new drugs and in keeping up-to-date. Drug bulletins can have a variety of sponsors, such as government agencies, professional bodies, university departments, philanthropic foundations and consumer organizations. They are published in many countries, are often free of charge, and are highly respected because of their unbiased information. Examples in English are: Drug and Therapeutics Bulletin (UK), Medical Letter (USA) and Australian Prescriber (Australia). A good independent drug bulletin in French is Prescrire; it is not free of charge.

National drug bulletins are appearing in an increasing number of developing countries, which include Bolivia, Cameroon, Malawi, the Philippines and Zimbabwe. The main advantages of national drug bulletins are that they can select topics of national relevance and use the national language.

Medical journals

Some medical journals are general, such as The Lancet, the New England Journal of Medicine or the British Medical Journal; others are more specialized. Most countries have their own national equivalents. Both types contain much information of relevance to prescribers. The general journals regularly publish review articles on treatment. The specialized journals include more detailed information on drug therapy for specific diseases.

Good medical journals are 'peer reviewed', that is, all articles are sent for independent expert review prior to publication. You can usually check whether journals meet this important criterion by reading the published instructions for submission of articles.

Some journals are not independent. They are usually glossy and often present information in an easily digestible format. They can be characterized as: free of charge, carrying more advertisements than text, not published by professional bodies, not publishing original work, variably subject to peer review, and deficient in critical editorials and correspondence. In the industrialized world they are promoted to the physician as a 'way to save time'. In fact reading them is a loss of time, which is why they are commonly referred to as 'throwaways'. Also be careful with journal supplements. They sometimes report on commercially sponsored conferences; in fact, the whole supplement may be sponsored.

So don't assume that because a review article or research study appears in print that it is necessarily good science. Thousands of 'medical' journals are published and they vary enormously in quality. Only a relatively small proportion publish scientifically validated, peer reviewed articles. If in doubt about the scientific value of a journal, verify its sponsors, consult senior colleagues, and check whether it is included in the Index Medicus, which covers all major reputable journals.

Verbal information

Another way to keep up-to-date is by drawing on the knowledge of specialists, colleagues, pharmacists or pharmacologists, informally or in a more structured way through postgraduate training courses or participation in therapeutic committees. Community based committees typically consist of general practitioners and one or more pharmacists. In a hospital setting they may include several specialists, a clinical pharmacologist and/or a clinical pharmacist. Such committees meet regularly to discuss aspects of drug treatment. In some cases they establish local formularies and follow up on their use. Using a clinical specialist as the first source of information may not be ideal when you are a primary health care physician. In many instances the knowledge of specialists may not really be applicable to your patients. Some of the diagnostic tools or more sophisticated drugs may not be available, or needed, at that level of care.

Drug information centres

Some countries have drug information centres, often linked to poison information centres. Health sworkers, and sometimes the general public, can call and get help with questions concerning drug use, intoxications, etc. Modern informatics, such as on-line computers and CD-ROM, have dramatically improved access to large volumes of data. Many major reference data bases, such as Martindale and Meylers Side Effects of Drugs, are now directly accessible through international electronic networks. When drug information centres are run by the pharmaceutical department of the ministry of health, the information is usually drug focused. Centres located in teaching hospitals or universities may be more drug problem or clinically oriented.

Computerized information

Computerized drug information systems that maintain medication profiles for every patient have been developed. Some of these systems are quite sophisticated and include modules to identify drug interactions or contraindications. Some systems include a formulary for every diagnosis, presenting the prescriber with a number of indicated drugs from which to choose, including dosage schedule and quantity. Prescribers can also store their own formulary in the computer. If this is done, regular updating is needed using the sources of information described here. In many parts of the world access to the hardware and software needed for this technology will remain beyond the reach of individual prescribers. In countries where such technology is easily accessible it can make a useful contribution to prescribing practice. However, such systems cannot replace informed prescriber choice, tailored to meet the needs of individual patients.

Pharmaceutical industry sources of information

Information from the pharmaceutical industry is usually readily available through all channels of communication: verbal, written and computerized. Industry promotion budgets are large and the information produced is invariably attractive and easy to digest. However, commercial sources of information often emphasize only the positive aspects of products and overlook or give little coverage to the negative aspects. This should be no surprise, as the primary goal of the information is to promote a particular product. Commercial information is often tailored to the prescriber's specific situation: information on an anti-nauseant given to a gynaecologist in a university hospital may differ from that given to a general practitioner in rural practice.

Usually the pharmaceutical industry uses a 'multi-track' approach. This means that the information is provided through a number of media: medical representatives (detail men/women), stands at professional meetings, advertising in journals and direct mailing.

From industry's point of view, medical representatives are usually very effective in promoting drug products, and much more effective than mailings alone. Often over 50% of the promotional budget of pharmaceutical companies in industrialized countries is spent on representatives. Studies from a number of countries have shown that over 90% of physicians see representatives, and a substantial percentage rely heavily on them as sources of information about therapeutics. However, the literature also shows that the more reliant doctors are on commercial sources of information only, the less adequate they are as prescribers.

In deciding whether or not to use the services of drug representatives to update your knowledge on drugs, you should compare the potential benefits with those of spending the same time reading objective comparative information.

If you do decide to see representatives, there are ways to optimize the time you spend with them. Take control of the discussion at the outset so that you get the information you need about the drug, including its cost. If your country has a health insurance scheme, check whether the drug is included in the list of reimbursable products. Early on in the discussion ask the representative to give you a copy of the officially registered drug information (data sheet) on the product under discussion, and during the presentation compare the verbal statements with those in the official text. In particular look at side effects and contraindications. This approach will also help you to memorize key information about the drug.

Always ask for copies of the published references on efficacy and safety. Even before reading these, the quality of the journals in which they appear will be a strong indication of the likely quality of the study. You should know that the majority of newly marketed drugs do not represent true therapeutic advances but are what is known as ‘me too’ products. In other words, they are very similar in chemical composition and action to other products on the market. The difference is usually in price; the most recently marketed drug is usually the most expensive! Seeing medical representatives can be useful to learn what is new, but the information should always be verified and compared with impartial, comparative sources.

Drug information from commercial sources is also issued as news reports, and as scientific articles in professional journals. Industry is also a major sponsor of scientific conferences and symposia. The line between objective and promotional information is not always clear. A number of countries and professional associations are tightening regulations controlling drug promotion to tackle this problem. Some journals now require that any sponsorship from the pharmaceutical industry should be mentioned in the article.

As mentioned above and as studies show, it is not good practice to use only commercial information to keep up-to-date. Although it may seem an easy way to gather information, this source is often biased towards certain products and is likely to result in irrational prescribing. This is particularly true for countries without an effective regulatory agency, because more drugs of sometimes doubtful efficacy may be available and there may be little control on the contents of data-sheets and advertisements.

WHO has issued Ethical Criteria for Medicinal Drug Promotion which contain global guidelines for promotional activities. The International Federation of Pharmaceutical Manufacturers’ Associations also has a code of pharmaceutical marketing practices. In several countries national guidelines exist as well. Most guidelines specify that the promotional information should be accurate, complete and in good taste. It is a very good exercise to compare a number of drug advertisements with the national or global criteria. Most guidelines also cover the use of samples and gifts, participation in promotional conferences and clinical trials, etc.

If you do use commercial information follow these ground rules. First, look for more information than advertisements contain. Second, look or ask for references, and check their quality. Only references in well established peer reviewed journals should be taken seriously. Then check the quality of the research methodology on which the conclusions are based. Third, check what your colleagues, and preferably a specialist in the field, know about the drug. Finally, always collect data from unbiased sources before actually using the drug. Do not start by using free samples on a few patients or family members, and do not base your conclusions on the treatment of a few patients!

Yet commercial information is sometimes helpful in a general sense, especially to know of new developments. However, comparative information from drug bulletins or therapeutic reviews is absolutely essential to help you evaluate the new drug in relation to existing treatments, and to decide whether you wish to include it in your personal formulary.

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The WHO Essential Medicines and Health Products Information Portal was designed and is maintained by Human Info NGO. Last updated: June 25, 2014