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Ovid: Oxford Handbook of General Practice

Editors: Simon, Chantal; Everitt, Hazel; Kendrick, Tony Title: Oxford Handbook of General Practice, 2nd Edition Copyright ©2005 Oxford University Press > Table of Contents > Chapter 3 – Prescribing Chapter 3 Prescribing Further information British National Formulary (BNF) http://www.bnf.org P.118
NHS prescriptions (1) ‘A doctor is a man who writes prescriptions till the patient either dies or is cured by nature’ John Taylor (1694–1761) At any one time, 70% of the UK population is taking medicines. ¾ of people >75y. are taking prescribed medicines and 36% of older people take ≥4 different medications on a regular basis. 1.7 million prescriptions are dispensed daily within the NHS to prevent illness, cure existing illness, and give symptomatic relief, costing >£6 billion/y. (>10% NHS costs). Prescribing forms a major part of any GP’s workload. Bad prescribing wastes resources, deprives patients of the chance to benefit, and may cause illness. Medicines should be prescribed only when necessary and, in all cases, benefits of prescribing should be weighed against risks. Prescription pre-payment certificate (PPC) If not entitled to free prescriptions but needing a lot of medication (>5 prescriptions/ 4mo. or >14/y.) it is cheaper for a patient to purchase a ‘pre-payment certificate’. There are 4 ways to purchase a PPC:

  • Internet http://www.ppa.org.uk
  • Telephone Tel: 0845 850 00 30
  • Post—form FP95 available from doctors’ surgeries and pharmacists or http://www.dh.gov.uk. Send completed form to PPC Issue Office, PO Box 854, Newcastle-upon-Tyne NE99 2DE
  • From a pharmacy registered to sell PPCs. List available at http://www.ppa.org.uk

Refunds Send PPC and letter explaining the reason for refund to PPC Issue Office (address above). Full refund may be claimed if <1mo. after purchase the holder becomes entitled to free prescriptions or dies. Partial refund may be claimed if the holder dies >1mo. after issue or if the holder becomes entitled to free prescriptions 1-4mo. after issue. Reclaiming money spent whilst awaiting exemption certificate or PPC Ask for official receipt at pharmacy when drug is paid for (FP57 England/EC 57 Scotland). Claim money back within 3mo. Drugs cheaper OTC The Consumer’s Association publishes a list of drugs with recommended retail price < the prescription charge and circulates it periodically with Drugs and Therapeutics Bulletin. Copies can be obtained from: Dept. DTB, Consumer’s Association, Castlemead, Gascoyne Way, Hertford, SG14 1LH. Prescriptions currently cost less in Wales, and the aim of the Welsh Assembly is to abolish prescription charges completely by 2007.

Table 3.1 Free prescription entitlement
Free prescription entitlement Action needed
  • Prescription for contraception
  • >60y. or <16y. or 16-18y. of age in full-time education
  • Patient or family receiving IS or income-based JSA
Tick box on reverse of prescription form
Pregnant women and women who have had a baby <12mo. ago (MatEx) Fill in form FW8 as soon as pregnancy confirmed—exemption certificate lasts 1y. from EDD. If form not completed until after baby is born exemption certificate lasts 12mo. after date of birth. Includes dentists’ charges.
Certain conditions (MedEx):

  • DM (unless diet controlled only)
  • Myxoedema/requirement for thyroxine or hypoparathyroidism
  • Epilepsy requiring continuous anticonvulsants
  • Permanent fistula (e.g. colostomy) needing stoma dressing/appliance
  • Hypoadrenalism (inc. Addison’s disease) needing replacement therapy
  • Hypopituitarism including diabetes insipidus
  • Myaesthenia gravis
  • Unable to go out without the help of another person due to a continuing physical disability
Fill in form FP92A (available from doctors’ surgeries).
Requires a doctor’s signature to confirm condition when applying for exemption. Certificate lasts 5y. or until 60th birthday if sooner.
War pensioners—prescriptions related to pensionable condition only Apply through Veterans’ Agency Tel: 0800 169 22 77
Low income and <£8000 savings (higher if in residential care or aged ≥60y.) or pending application for any benefit listed above Students are eligible. Includes opticians’ and dentists’ charges. Apply through NHS low income scheme (LIS) on form HC1 Tel: 0845 850 1166 or
imagesLeaflet HC11 (Help with Health Costs) is available from Post Offices, some pharmacies, GP surgeries, or Department of Health, PO Box 777, London SE1 6 X H.

NHS prescriptions (2) Legal responsibility for prescribing lies with the person who signs the prescription form British National Formulary (BNF) contains a list of all drugs which a registered medical practitioner can prescribe on NHS prescription. Does not include homeopathic drugs which can be prescribed on NHS prescription or aids and appliances. Dentists and nurses have their own limited formulary. http://www.bnf.org Claiming for items dispensed by a non-dispensing GP All GPs may claim payment for dispensing certain items which are supplied and personally administered by the GP or practice staff on their behalf Claims are made on form FP10 (GP10) to the PPA and must state the name of the patient, item dispensed, and manufacturer of the item Claimable items are:

  • Vaccines
  • Anaesthetics
  • Injections
  • Sutures
  • Skin closing strips
  • IUCDs
  • Contraceptive caps/diaphragms
  • Diagnostic reagents
  • Pessaries which are appliances (e.g. ring pessary)

Different arrangements apply for high-volume vaccines e.g. influenza Prescription writing NHS prescriptions are written on form FP10 (GP10 in Scotland). They should be legible and in indelible ink. They are valid for 13wk. from the date written on them. Include:

  • Patient details—full name, address, and age/date of birth if <12y.
  • Date
  • Full name of drug (not abbreviated) with quantity to be supplied and dose interval (avoid the use of decimal points e.g. quantities <1g, write in mg). If you want a description of the drug included on the label, write it on the prescription.
  • Deletion of any unused space (e.g. by striking through)
  • Signature of the prescriber in ink
  • Name and address of the prescriber

Special rules apply for controlled drugs—p.132 Computer issued prescriptions (form FP10(C)) Should contain the same information as their hand-written equivalents. They must still be signed in ink by the responsible GP. Prescriptions for controlled drugs (with the exception of phenobarbitone) must not be printed from computer—blank forms may be printed, but details apart from the name and address of the GP and their health authority and prescribing number must be handwritten. Prescriptions for phenobarbitone can be computer generated but the date must be handwritten. Guidelines are available from the Joint Computing Group of the GPC and RCGP (summary is available in the BNF http://www.bnf.org) P.121
Non-NHS prescriptions The same rules apply to the writing of private prescriptions as NHS prescriptions but private prescriptions should not be written on FP10 forms (normally headed note paper is used). There are no restrictions upon which drugs can be prescribed. Nurse prescribers (BNF—Appendix NPF). List of preparations approved by the Secretary of State which may be prescribed on form FP10P (form HS21(N) in Northern lreland, form GP10(N) in Scotland, forms FP10(CN) and FP10(PN) in Wales) by nurses for NHS patients. Nurses who have undergone additional training can prescribe from the nurse prescribers’ extended formulary list. Dentists (BNF—Appendix DPF). Can prescribe medication for dental conditions to their NHS patients on form FP10 (D) (GP14 in Scotland). Emergency supply of medicines by pharmacists In emergency situations, pharmacists can dispense prescription only medicines (POM). In general, <5d. supply can be dispensed. Patient information Since 1994, all newly licensed/relicensed medicines dispensed in an original pack must be accompanied by a patient information leaflet (PiL). Despite the fact most drugs are now supplied with PiLs, doctors should make patients aware of ‘substantial or special risks when offering treatment’. How much information to give is unclear. Information regarded as important by patients is: name of the drug; what to do if a dose is missed; purpose of treatment; precautions (e.g. effect on driving); when and how to take the medicine; problems with alcohol and other drugs; unwanted effects and what to do about them. Security of prescriptions Prescription theft and fraud is common and wastes valuable NHS resources. Basic precautions:

  • Prescriptions—should not be left unattended at reception desks; should not be left in a car where they might be visible; and, when not in use, should be kept in a locked drawer, both at the surgery and at home.
  • Writing prescriptions—draw a diagonal line over the blank part of the form under the prescription; write the quantity in words and figures for drugs prone to abuse (even if not controlled drugs); make alterations clear and unambiguous and add your initials against any altered items.

If prescription fraud is suspected Tel: 08702 400 100 Further information Counter Fraud and Security Management Service (CFSMS) http://www.cfsms.nhs.uk P.122
Cost-effective prescribing Generic prescribing Use of generic names when prescribing is one of the simplest ways to ↓ cost of drugs to the NHS, but only 63% drugs prescribed by GPs in the UK are prescribed generically. Every marketed drug has a chemical name, generic name, and a proprietary or brand name. For as long as the drug’s patent is valid, the company that developed the drug will derive income from prescriptions, whatever the name on the prescription. Once the patent has expired, competitors can manufacture the drug and market it under its generic or an alternative brand name. If the drug is prescribed generically, the pharmacist decides which brand to supply and market forces drive price ↓. Advantages of generic prescribing Cost ↓, professional convenience (there are often several brand names for one drug—using generic names, everyone knows they are talking about the same thing), ↓ inconvenience to the patient (pharmacists do not stock each brand of a given drug and, if prescribed by brand name, may have to order a supply; usually generic preparations of all commonly used drugs are available). Reasons not to prescribe generically

  • Drugs with a low therapeutic index: e.g. lithium, carbamazepine, phenytoin, ciclosporin—dosage is carefully titrated against plasma concentration or response. Small differences in plasma concentrations can be clinically significant.
  • Modified release formulations: e.g. diltiazem, nifedipine, amino phylline, or theophylline products. Composition and pharmokinetic properties are very difficult to standardize.
  • Formulations containing ≥2 drugs: Some do have generic names (e.g. co-amilofruse 5/40, co-proxamol); others do not. Don’t make up a generic name if there isn’t one.

Evidence-based prescribing Decisions on what to prescribe and when, were, in the past, largely based on guess work or faith. With the advent of information from randomized controlled trials and their evaluation using systematic reviews and other techniques, such decisions can now be based (at least in part) on scientific evidence. Failure to do this may cause patients to suffer unnecessary side-effects of ineffective drugs, deprive patients of the chance to benefit from effective treatments, and waste valuable resources. Sources of information: p.82,83. NICE p.20 Rationing p.11 Practice formularies An agreed practice formulary is an effective way to limit prescribing and costs of prescribing. Compiling a formulary from scratch is a daunting prospect but there are many formularies available, which can then be modified according to evidence that emerges and review within a practice (contact PCO prescribing lead). When compiling or reviewing a formulary consider: evidence of efficacy; safety; cost effectiveness; local policy. P.123
Prescription Pricing Authority (PPA) Special health authority with 4 functions:

  • To scrutinize pricing and payment to contractors for dispensing of NHS prescriptions
  • Prevention of prescribing and dispensing fraud in the NHS
  • Provision of prescribing and dispensing information to the NHS (excluding hospital dispensing)
  • Management of the NHS low income scheme.

PACT data Since 1988, the PPA has provided GPs in England and Wales with regular information on their prescribing habits and costs through Prescribing analysis and cost (PACT). 2 levels of information:

  • Standard report: Sent to each GP with a prescribing number on a quarterly basis. Outer pages—practice or GP level details of cost and number of prescriptions for that quarter; top 20 drugs which drive the GP’s prescribing costs; top 40 BNF sections; and average cost/prescription. Centre pages—information on a topical aspect of prescribing and related practice-specific feedback.
  • Prescribing catalogue: Issued only at the request of the prescriber. Full inventory of prescriptions during the period specified (1-24mo.).

It can be used to improve prescribing habits, ↓ prescribing costs, and to produce formularies and prescribing policies. A similar scheme operates in Scotland (Scottish Prescribing Analysis—SPA). Further information UK Medicines information http://www.ukmi.nhs.uk Electronic medicines compendium http://www.medicines.org.uk Prescription Pricing Authority http://www.ppa.org.uk P.124
Medicines management and concordance Medicines management Defined as ‘facilitating the maximum benefit and minimum risk for medicines for individual patients’. Encompasses the way medicines are selected, procured, delivered, prescribed, administered, and reviewed to optimize use. Components are:

  • Optimizing a medication regime (right drug at right time);
  • Facilitating adherence to medication, including beliefs and fears as well as physical problems;
  • Organizing supply and administration support, such as repeat dispensing systems;
  • Providing monitoring and feedback systems.

Concordance Is a process of prescribing and medicine taking based on partnership. Patient concordance (or rather lack of it) is a major challenge in general practice. For drugs to be optimally effective they should be taken as directed by the prescriber. Concordance sufficient to attain therapeutic objectives occurs about ½ the time—1:6 patients take medication exactly as directed; 1:3 take medication as directed 80–90% of the time; 1:3 take medication 40–80% of the time; the remaining 16–17% take medication as directed <40% of the time. 20% prescriptions are never ‘cashed’. ‘White-coat concordance’ Phenomenon in which 90% of patients take regular medication as directed for a period before a check up—may mask effects of non-concordance. Consequences of non-concordance Failure to attain therapeutic targets e.g. failure to take antihypertensive medication ↓ reduction of stroke by 30–50%; wastage of precious resources (~£230 million worth of medicines are returned to pharmacies each year for disposal—the true quantity wasted is many times that). Causes of non-concordance

  • Patient beliefs: Strongest predictor of compliance—how natural a medicine is seen to be, the dangers of addiction and dependence, the belief that constant use may lead to ↓ efficacy have all been shown to influence compliance.
  • Lifestyle choices
    • Unpleasant side-effects (especially if not pre-warned)
    • Inconvenience (e.g. multiple daily dosage regimes—though little difference between od and bd dosage)
    • No perceived benefit
  • Information: Instructions not understood or poor understanding of the condition/treatment.
  • Practical: Forgetfulness; inability to open containers.
  • Professional
    • Doctor-patient relationship (link between patient satisfaction with consultation and subsequent concordance).
    • Inappropriate prescribing; mistakes in administration/dispensing.

Improving concordance ~70% patients want to be more involved in decisions about treatment. Doctors underestimate the degree to which they instruct and overestimate the degree to which they consult and elicit their patients’ views. The doctor’s task is, by negotiation, to help patients choose the best way to manage their problem. Patients are more likely to be motivated to take medicines as prescribed when they:

  • Understand and accept the diagnosis
  • Agree with the treatment proposed
  • Have had their concerns about the medicines specifically and seriously addressed.

Ways to improve concordance

  • Use simple language and avoid medical terms.
  • Discuss reasons for treatment and consequences of not treating the condition ensuring information is tailored, clear, accurate, accessible, and sufficiently detailed.
  • Seek the patient’s views on their condition.
  • Agree course of action before prescribing.
  • Explain what the drug is, its function, and (if known and not too complex) its mechanism of action.
  • Keep the drug regime as simple as possible—od or bd dosing preferable, especially long-term.
  • Seek the patients views on how they will manage the regime within their daily schedule and try to tie in with daily routine (e.g. take one in the morning when you get up).
  • Discuss possible side-effects (especially common or unpleasant side-effects).
  • Give clear verbal instructions and reinforce with written instructions if complex regime, elderly, or understanding of patient is in doubt.
  • Deal with any questions the patient has.
  • Repeat information yourself and also ask patients to repeat information back to you to reinforce.
  • If necessary, arrange review within short time of starting medicine to discuss progress or queries, or arrange follow-up by another member of the primary healthcare team (e.g. asthma nurse to check inhaler technique 2–3wk. after starting inhaler).
  • Address further patient questions and practical difficulties at follow-up.
  • Monitor repeat prescriptions.

Further information Medicines Partnership: from compliance to concordance. http://www.concordance.org Managing Medicines http://www.managingmedicines.com P.126
Repeat prescribing 80% of NHS prescriptions are for repeat medication. Good practice is essential to ensure wastage (<10% of total prescribing costs) is kept to a minimum. Essential elements are:

  • Written explanation—repeat prescribing process for patients and carers
  • Practice personnel with dedicated responsibility—ensure patient recall and regular medication review
  • Agreed practice policies—for repeat prescriptions e.g. duration of supply; procedure if someone ‘runs out’ but isn’t authorized to have more
  • Authorization check—each time a prescription is signed
  • Compliance check—for under or over-use (prescription frequency)
  • Equivalence check—all regular prescriptions are for the same duration of treatment so that prescription requests can be synchronized
  • Regular housekeeping—keep records of medication up to date (including dosage instructions); particular care after hospital discharge when medication could have been substantially changed
  • Training of practice staff

Review process Invite patient ± carer. Areas to cover:

  • Explain what you want to do in the review and the reasons for it
  • Compile a list of all medicines being taken/used including: prescribed medication; OTC drugs; herbal/homeopathic medicines; illicit drugs; and medicines borrowed from others, and compare the list of drugs generated with the prescription record
  • Concordance—find out whether and how medication is taken
  • Explore understanding of purpose of medication and consequences of not taking it, and how much, how often, when
  • Discuss misconceptions/queries
  • Ask about side-effects
  • Review relevant monitoring tests e.g. TFTs; INR; HbA1c
  • Review practical aspects—problems ordering/receiving repeat prescriptions; using medicines e.g. problems opening containers; with formulations e.g. difficulty swallowing tablets; reading labels—can request large print; remembering to take medication—consider reminder chart, Dossett box, altering times of doses to fit in better with daily schedule
  • Check necessity and appropriateness of all prescriptions (see Figure 3.1)

Further information Cantrill et al. (1998) Quality in Health Care; 7: 130–5. DOH: Medicines and older people. http://www.dh.gov.uk UK medicines information: http://www.ukmi.nhs.uk Electronic medicines compendium: http://www.medicines.org.uk

Figure 3.1 Deciding whether a prescribed drug is appropriate

Adverse drug reactions ‘I don’t want two diseases—one nature-made and one doctor-made’ Napolean Bonaparte, St. Helena, 1820 In 5–17% hospital admissions, an adverse drug reaction is implicated. Any drug may produce unwanted or unexpected effects. Common side-effects are listed in the BNF or drug data sheet but any patient can have an allergic reaction or idiosyncratic response to any drug. The possibility of rare (<1:5000) or delayed reactions means that safety of new medicines cannot be established until they have been used for some time in a large population. A 24h. freefone service is available for information and advice about suspected adverse reactions (Tel: 0800 731 6789). Classification

  • Allergy—anaphylaxis, allergic rash
  • Toxic effect—e.g. ataxia with carbamazepine if dose too high
  • Predictable—well recognized side-effect e.g. dry mouth with amitriptyline, GI bleeding with aspirin
  • Idiosyncratic—unpredictable and unique to the individual
    • Type A: common and relates to the pharmacology of the drug e.g. constipation with opiates
    • Type B: rare, unpredictable, and often serious

Defective medicines A medicine which does not conform to its specification is deemed defective. Report suspected defective medicine, with as much detail as possible on product and nature of defect to: The Defective Medicines Report Centre, Medicines and Healthcare Products Regulatory Agency, Room 1801, Market Towers, 1 Nine Elms Lane, London SW8 5NQ Tel: 020 7273 0574 or 020 7210 3000. Suspected adverse reactions To any therapeutic agent (whether OTC, herbal/alternative medication, or prescribed by a doctor) should be reported to the Medicines and Healthcare Products Regulatory Agency (MHRA—formerly MCA—CSM Freepost, London SW8 5BR). Forms (‘Yellow cards’) are available from that address or in the back of the BNF. Alternatively, report online at http://www.mca.gov.uk

  • For new drugs (marked [black down-pointing triangle] in BNF): Doctors are asked to report all reactions whether or not causality is clear.
  • For established drugs: Doctors are asked to report all reactions in children; all serious suspected reactions, even if the effect is well documented (e.g. anaphylaxis, blood disorders, renal or liver impairment, drug interactions) but not well-known; relatively minor side-effects (e.g. constipation with opioids, insomnia with SSRIs).

Prevention of adverse reactions

  • Never use a drug unless there is a good indication.
  • Ask the patient if they have had reactions previously to a drug, before prescribing.
  • Ask about other drugs the patient is taking (including self-medication). Consider interactions.
  • Consider the effects of age and hepatic or renal impairment.
  • Prescribe as few drugs as possible (the more drugs, the more likelihood of interactions).
  • Give clear instructions about how to take the drug.
  • Wherever possible, use a drug you are familiar with. If using a new drug, be alert to side-effects.
  • Warn the patients about potentially serious side-effects (e.g. risk GI ulceration with NSAIDs).

Consumer Protection Act (1987) If a patient is damaged by a defective product, liability falls on the producer (unless outside the EC, when it falls to the importer). If the importer cannot be identified, liability falls on the supplier. This is important for GPs. Those who dispense are at greatest risk, but all GPs occasionally supply drugs in an emergency or for procedures within the surgery (vaccinations, minor surgery, contraception). Always record manufacturer, batch number, and expiry date when using such drugs and keep records of storage of drugs and maintenance of equipment. Poisoning p.1078 Poisons information UK National Poisons Information Service Tel: 0870 600 6266 TOXBASE poisons database http://www.spib.axl.co.uk P.130
Licensing In the UK, the Medicines Act (1968) makes it essential for anyone who manufactures or markets a drug for which therapeutic claims are made, to hold a licence. The Licensing Authority, working through the Medicines and Healthcare Products Regulatory Agency (MHRA), can grant both manufacturer’s licence and marketing authorization (which allows a company to market and supply a product for specified indications). Although doctors usually prescribe according to the licensed indications, they are not obliged to. Prescribing outside licence There may be occasions when a doctor feels it is necessary to prescribe outside a drug’s licence:

  • Generic formulations for which indications are not described. The prescriber has to assume the indications are the same as for branded formulations.
  • Use of well-established drugs for proven but not licensed indications e.g. amitriptyline for neuropathic pain.
  • Use of drugs for conditions where there are no other treatments (even if the evidence of their effectiveness is not well proven). This often occurs in secondary care when new treatments become accepted. GPs may become involved if a patient is discharged to the community and the GP is asked to continue prescribing. The person signing the prescription is legally responsible.
  • Use of drugs not covered by their licensed indications. Frequently occurs in paediatrics.

Before prescribing any medication (whether within or outside the licence), weigh risks against benefits. The more dangerous the medicine, and the flimsier the evidence-base for treatment, the more difficult it is to justify the decision to prescribe. When prescribing licensed drugs for unlicensed indications inform patients and carers of what you are doing and why. Explain that the patient information leaflet (PiL) will not have information about the use of the drug in these circumstances. Record in the patient’s notes your reasons for prescribing outside the licensed indications for the drug. Clinical trials Drug discovery and development is a protracted process (>10y.) costing huge sums of money ([approximate, equals]100 million). Clinical testing is conventionally divided into 5 stages:

  • Phase I trials: clinical pharmacology in normal volunteers.
  • Phase II trials: preliminary small-scale studies.
  • Phase III trials: large-scale trials (several thousand patients often). Once complete, application is made for a licence to sell the drug.
  • Phase IV trials: post-marketing surveillance—large-scale follow-up of patients using the drug to establish evidence of long-term efficacy and safety.
  • Phase V trials: further trials to compare efficacy and safety with other marketed compounds and explore new indications.

GPs are unlikely to be involved before phase III. Taking part in trials can benefit both patients and practice, but consider proposals carefully before embarking on a project (see below). Research in general practice p.92 Questions to ask before agreeing to take part in a clinical trial

  • Are the aims and objectives of the study defined?
  • What is the design?
  • Which drug is to be tested?
  • What are the end-points?
  • Are the criteria for identifying patients clear and explicit?
  • Are the numbers to be recruited specified and feasible?
  • Are the observations to be made clearly and vigorously defined?
  • Are the arrangements for providing information to patients and for obtaining informed consent satisfactory?
  • Has ethical approval of the study been obtained?
  • Are the financial arrangements clearly set out (minimum—reimbursement of patients’ expenses and practice expenses)?
  • Has adequate provision been made for compensation in the event of injury to patients in the course of the study?

Controlled drugs (CDs) Prescriptions ordering CDs in schedules 2 or 3 must be hand written (with the exceptions of temazepam capsules and phenobarbitone—for which date must be handwritten) and signed and dated by the prescriber. Prescriptions must state:

  • Name and address of the patient
  • Form and strength of the preparation
  • Total quantity of the preparation or number of dose units in words and figures
  • Dose the patient should take

For example: Morphine sulphate 10mg (ten milligram) tablets, one to be taken twice daily. Please supply 60 (sixty) tablets, total 600 (six hundred) milligrams. A prescription may request the drug to be dispensed in instalments, when the amount in each instalment and interval between instalments should be stated. Prescriber’s responsibilities

  • To avoid creating dependence by unnecessarily introducing CDs to patients.
  • Careful monitoring to ensure the patient does not gradually ↑ the dose of drug to a point where dependence becomes more likely.
  • To avoid being an unwitting source of supply for addicts. If you suspect an addict is going round surgeries with intent to obtain supplies, contact your PCO so that they can issue a warning to other practices.

Notification of drug misusers Doctors are expected to report, on a standard form, cases of drug misuse to their regional or national drug misuse database or centre. All types of problem drug misuse should be reported. Databases cannot be used as a check on multiple prescribing as data are anonymized.

Table 3.2 Regional and national drug misuse databases/centres
Region Area code telephone number (fax)
South East (West) and Eastern 01865 226734 (226652)
Thames and South East (East) 020 7594 0811 (7594 0866)
Merseyside and Cheshire 0151 231 4319 (231 4320)
North Western 0161 772 3782 (772 3445)
Northern and Yorkshire 0113 295 1337 (295 1310)
South West 0117 918 6880 (918 6883)
Trent 0116 225 6360 (225 6370)
West Midlands 0121 580 4331 (525 7980)
Scotland 0131 551 8715 (551 1392)
Wales 029 2082 6260 (2082 5473)
Northern Ireland 028 9052 2421 or 9052 0532

Misuse of Drugs Act (1971) Controls manufacture, supply, and possession of CDs. Penalties for offences are graded according to perceived harmfulness of the drug into 3 classes:

  • Class A: e.g. cocaine, diamorphine (heroin), methadone, LSD, ecstasy
  • Class B: e.g. oral amphetamines, barbiturates
  • Class C: e.g. most benzodiazepines, androgenic and anabolic steroids, cannabis (recent downgrading)

Misuse of Drugs Regulations (1985) Defines persons authorized to supply and possess CDs while carrying out their professions and describes the way in which this is to be done. 5 schedules of drug:

  • Schedule 1: Drugs not used for medicinal purposes e.g. LSD. Possession and supply prohibited except with special licence.
  • Schedule 2: Drugs subject to full CD controls (written dispensing record, kept in locked container, CD prescription regulations) e.g. diamorphine, cocaine, pethidine.
  • Schedule 3: Partial CD controls (as schedule 2 but no need to keep register—some drugs subject to safe custody regulations) e.g. barbiturates, temazepam, meprobamate, buprenorphine.
  • Schedules 4 and 5: Most benzodiazepines, anabolic and androgenic steroids, HCG, growth hormone, codeine. Controlled drug prescription requirements do not apply, nor do safe custody requirements.

For patients or doctors travelling abroad with schedule 2 or 3 drugs, an export licence may be required. Further details can be obtained from the Home Office (Tel: 020 7273 3806). Patient applications must be accompanied by a doctor’s letter giving details of: patient’s name and current address; quantities of drugs to be carried; strength and form of drugs; dates of travel. For clearance to import the drug into the country of destination, it is advisable to contact the Embassy or High Commission of that country prior to departure. Prescribing for addicts Only practitioners who hold a special licence from the Home Office may prescribe diamorphine, diconal (dipipanone), or cocaine for the treatment of drug addiction (though any doctor can prescribe these drugs for addicts if they need them for relief of pain). Management of drug addiction—p.240. P.134
Prescribing for special groups (1) Palliative care p.999,1000,1001,1002,1003,1004,1005,1006,1007,1008,1009,1010,1011,1012,1013,1014 Children Keep all medicines out of the reach of children (and preferably in a locked cupboard).

  • Children differ from adults in their response to drugs. Consult BNF or Paediatric Vade Mecum before prescribing unfamiliar drugs. Always check dose carefully. Many drugs are not licensed for use with children.
  • Paediatric suspensions often contain sugar. For long-term use or children having frequent prescriptions consider sugar-free versions.
  • Do not advise adding medicines to infant feeding bottles—they may interact with milk and dose will be ↓ if not all the contents are drunk
  • Information on drugs used to treat rare paediatric conditions: Alder Hey Children’s Hospital (Tel: 0151 252 5381) or Great Ormond Street Hospital (Tel: 020 7405 9200).
  • Report all adverse reactions on Yellow Cards—p.128

The elderly Use of medicines ↑ as people get older. Medicine-related problems are assessed as part of the joint social and healthcare assessment procedure, prompting specialist assessment if problems are identified. Prescribing for the elderly is a priority area highlighted in the NSF for older people (p.992). It sets targets that all people ≥75y. should have their medication reviewed annually, with those taking ≥4 medicines having a 6mo. review. By 2004, all PCOs should also have schemes in place to ensure older people get more help from pharmacists in using their medicines. Problems commonly encountered:

  • Polypharmacy: Elderly people often have multiple problems—it is easy to keep adding drugs for each new problem leading to confusion, poor compliance, and multiple interactions and side-effects. Review repeat medication regularly and stop ineffective or redundant drugs (p.127). Before prescribing a new drug, consider whether it is necessary and, if so, whether the drug regime can be simplified.
  • Specific medicines: Need close monitoring e.g. warfarin, NSAIDs, diuretics, digoxin, hypnotics, psychotropics.
  • Form of the medicine: Swallowing tablets can be difficult for elderly people. Consider using liquid preparations or, if no suitable preparation is available and the drug is in tablet form, crushing it with a spoonful of semi-solid ice cream.
  • Confusion post-discharge: Up to ½ all patients are inadvertently prescribed the wrong medication after hospital discharge.
  • Drug hoarding/self-medication: Especially if there have been recent changes in medication, it is common for elderly people to have a back stock of drugs and to continue taking their old drugs alongside new ones. Many elderly people also self-medicate extensively with OTC preparations. If necessary, do a home visit to sort out the drugs.
  • P.135

  • ↑ susceptibility to side-effects: Common. Sometimes due to impaired renal function (always assume any elderly person has moderate impairment if renal function is not known). Elderly people also tend to be hypersensitive to effects of CNS drugs e.g. benzodiazepines—use with care.
  • Social and personal factors: Low level of home support; physical factors e.g. poor vision, poor hearing, or poor manual dexterity; and mental state e.g. confusion/disorientation, depression—can all affect the ability of an older person to take medication.

Guidelines for prescribing for the elderly

  • Limit the range of drugs you use: Prescribe from a limited array of drugs that you know well.
  • Repeats and disposal: Tell patients how to get more tablets and what to do with any left over if a drug is stopped. Monitor the frequency of repeat prescriptions. Review repeat prescriptions regularly (p.126).
  • ↓ the dose: Start with 50% of the adult dose. Avoid drugs likely to cause problems (e.g. long-acting antidiabetic agents such as glibenclamide).
  • Review regularly: Consider whether each drug could be stopped or the regime simplified. Consider lowering dosage of drugs if renal function is deteriorating. Involve carers if appropriate.
  • Simplify regimes: Use od or bd regimes wherever possible.
  • Explain clearly: Put precise instructions on the drug bottle; when prescribing give written instructions about how the drug should be taken. Ensure explanations are given to carers as well as patients, where appropriate.
  • Consider method of administration: Bottles with child-proof tops are often impossible for arthritic hands to open. Suggest the patient asks the chemist for a standard screw cap. Drug administration boxes in which the correct tablets are stored in slots marked with the day and time of administration can be helpful. They are available from pharmacists and can be filled by the patient, a carer, friend, or relative. Medication reminder charts can also be helpful.

Further information Zermansky et al. (2001) BMJ 323: 1340–4 DOH: Pharmacy in the future: Implementing the NHS Plan—a programme for pharmacy in the National Health Service. http://www.dh.gov.uk DOH: Medicines and older people. http://www.dh.gov.uk UK medicines information http://www.ukmi.nhs.uk/ Electronic medicines compendium: http://www.medicines.org.uk P.136
Prescribing for special groups (2) Borderline substances BNF Appendix 7 For certain conditions, foods and toilet products can be regarded as drugs and prescribed under the NHS (e.g. gluten-free foods for coeliac disease, nutritional supplements for disease-related malnutrition). The Advisory Committee on Borderline Substances advises on which products are available for certain specified conditions. Products should not be prescribed for any other condition. Use form FP10 (GP10 in Scotland) and endorse with the letters ACBS. Pregnancy Drugs taken by the mother can harm the foetus at any stage in pregnancy. Mechanisms:

  • 1st trimester: Teratogenesis causing congenital malformations. Greatest risk—wk. 3–12.
  • 2nd and 3rd trimesters: Toxic effects; effects on growth/development.
  • Around labour: May affect labour or have adverse effects on the newborn baby.

Only prescribe if essential, especially in the 1st trimester. Stick to tried and tested drugs when possible (see BNF Appendix 4 for list of drugs with known affects); use smallest effective-dose; avoid new drugs. Further information BNF Appendix 4; National Teratology Information Service Tel: 0191 232 1525. Breast-feeding Drugs taken by a breast-feeding mother can affect the child by inhibiting lactation or entering the milk and causing toxicity to the infant. Therapeutic doses in the mother can cause toxicity in the infant if the drug is concentrated in milk (e.g. iodides). Avoid prescribing wherever possible. Stick to tried and tested drugs (see BNF Appendix 5). Renal impairment Renal function ↓ with age but may not be reflected by raised creatinine due to ↓ muscle mass. Always assume mildmoderate renal failure if prescribing for the elderly. Renal impairment can change the effects of drugs by:

  • Inability to excrete drug: May cause toxicity. Dose reduction or increase in interval between doses may be necessary.
  • Increased sensitivity to drugs: (even if elimination is unimpaired).
  • Poor tolerance of side-effects: Nephrotoxic drugs may have more serious side-effects.
  • Lack of effectiveness: When renal function is reduced.

In general practice, serum creatinine is a rough guide to renal function:

  • Mild renal impairment—creatinine 150–300µmol/l
  • Moderate renal impairment—creatinine 300–700µmol/l
  • Severe renal impairment—creatinine >700µmol/l

Further information BNF Appendix 3; patients on dialysis—consult local renal unit. P.137
Hepatic impairment Problems don’t tend to arise until late stages of liver failure when there is jaundice, ascites, or evidence of encephalopathy. Problems are due to:

  • Impaired drug metabolism: Many drugs are metabolized by the liver. In severe liver failure, dose may need to be ↓ +/- dosage interval ↑. A few drugs are excreted in the bile unchanged and may accumulate in patients with obstructive jaundice (e.g. rifampicin, fusidic acid).
  • Hypoproteinaemia: Liver failure is invariably associated with low plasma protein. This affects binding of drugs. Highly protein-bound drugs (e.g. phenytoin, prednisolone) can become toxic in normal dosage.
  • Hepatotoxicity: Liver toxicity will have increased effect if hepatic reserve is already reduced.
  • Clotting: Blood clotting factors are made in the liver. In liver disease, effects of oral anticoagulants are increased.
  • Encephalopathy: Drugs that depress cerebral function (e.g benzodiazepines, opiates) can precipitate encephalopathy due to severe liver failure.
  • Fluid retention: Drugs causing fluid retention (e.g. NSAIDs) make oedema and ascites worse.

Further information BNF Appendix 2 (list of drugs to be avoided/used with caution). Driving whilst taking drugs p.202 or http://www.dvla.gov.uk/at_a_glance/content.htm Further information UK medicines information http://www.ukmi.nhs.uk Electronic medicines compendium http://www.medicines.org.uk P.138
Drugs and sport Most sport regulating bodies have strict codes regarding drug use by participating sportsmen. Although broadly similar, regulations may differ in detail. Prohibited classes of drugs

  • Stimulants—e.g. amphetamine, caffeine (above 12mcg/ml), ephedrine, certain β2 agonists.
  • Narcotics—e.g. diamorphone, pethidine, methadone.
  • Anabolic agents—e.g. nandrolone, DHEA, testosterone.
  • Diuretics—e.g. frusemide, bendrofluazide.
  • Peptide and glycoprotein hormones and analogues—e.g. growth hormone, erythropoietin.

Classes of drugs subjected to restrictions

  • Alcohol and marijuana—restricted in certain sports.
  • Local anaesthetics—local or intra-articular injection only (provide written notification of administration for relevant medical authority).
  • Corticosteroids—topical, inhaled, or local/intra-articular injection only (provide written notification of administration for relevant medical authority).
  • β-blockers—restricted in certain sports.

Anabolic steroid misuse Significant problem in the UK (5% in gyms and fitness clubs). Drugs are often used in complicated regimes at high doses to ↑ lean muscle mass and ↓ body fat. Side-effects include: ↑ cholesterol, ↑ BP, gynaecomastia, ↑ LFTs, testicular atrophy, baldness, acne, and mood changes. Other drugs may be taken in conjunction with anabolic steroids to ↓ these side-effects. Doctors who prescribe or collude in the provision of drugs or treatment with the intention of improperly enhancing an individual’s performance in sport risk losing their GMC registration. This does not preclude the provision of any care or treatment where the doctor’s intention is to protect or improve the patient’s health. Further information UK Sport Produces a card giving more detailed information. Available from UK Sport, 40, Bernard Street, London WCA 1ST Tel: 020 7211 5100 http://www.uksport.gov.uk (information resources). Status of a particular medicine may be checked on the Drug Information Line Tel: 0800 528 0004 or http://www.uksport.gov.uk/did

Table 3.3 Treatment of common conditions for sportsmen
  Allowed Banned
Asthma Sodium cromoglycate, theophylline. Inhaled salbutamol, terbutaline, salmeterol, beclomethasone, or fluticasone.
Provide written notification of administration for relevant medical authority.
Products containing sympathomimetics e.g. ephedrine, isoprenaline, fenoterol, rimiterol, orciprenaline.
Cold/cough All antibiotics, steam and menthol inhalations, permitted antihistamines, terfenadine, astemizole, pholcodine, guaiphenasin, dextromethorphan, paracetamol. Products containing sympathomimetics e.g. ephedrine, pseudoephedrine, phenylpropanolamine.
Diarrhoea Diphenoxylate, loperamide, products containing electrolytes (e.g. Dioralyte). Products containing opioids e.g. morphine.
Hayfever Antihistamines, nasal sprays containing a corticosteroid or xylometazoline, eye-drops containing sodium cromoglycate. Products containing ephedrine or pseudoephedrine.
Pain Codeine, paracetamol, all NSAIDs, dextropropoxyphene. Products containing opioids, caffeine.
Vomiting Domperidone, metoclopramide, prochlorperazine, cinnarizine.  

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