Drug History and Introduction to Prescribing

Drug History and Introduction to Prescribing

Dr Andrew Stein, Consultant Nephrologist, UHCW

Outline of Talk

• Drug History

• Introduction to Prescribing

• Learning Objectives (LO): British National Formulary (BNF) and Formularies

• Quiz

Drug History

Why is it important?

• Make patients better

• Prevent (or reverse) harm to patients

• Prescribing errors very common

• They are the single most preventable cause of patient injury

• Junior doctors: most serious errors occur in prescribing and communication (esp handover)

• Good idea of PMH

Prescribing Errors

• 18,820 patients admitted to hospital over a six-month period

• 1,225 related to an adverse drug reaction (ADR; prevalence 6.5%)

• ADR led directly to admission in 80% cases

• Majority (72%) of these admissions were avoidable

• Bed stay was eight days (4% hospital bed capacity)

• Annual cost to NHS was £466 million pa

Pirmohamed M, BMJ 2004

If do one thing well, whilst clerking as F1-2 ..

• Take a good drug history

• No one else will, ie doctors that follow you

• Or state that you are not doing it (unable to, and why)

Information Sources

• Patient

• Family or carer

• GP (recent referral letters)

• Recent discharge letters

• Tablets themselves (weekly packs)

• Medication list (actual)

• Pharmacy (local)

• Ask pharmacist (reconciliation)

Interviewing the Patient

• Introduce yourself

• “My name is Dr Stein and I am your doctor”

• (Ps insert your name above)

• I would like to know about your tablets (start with open questions)

Drug History

• “Are you taking any tablets at the moment?”

• “What do you take that for?”

• “How many times a day do you take that tablet?

• “How many do you take? Do you know the strength of the tablets?”

• “Do you buy any other medication from the chemist (OTC) or internet?”

• “Do you take any other drugs (herbal or recreational)?”

Drug History (Repeat)

• It is so important, start again

• So you are on ‘x statin’ and ‘y pril’ .. anything else?

• Anything else?

• Are you sure?

Drug History (Specific)

• Oral contraceptive (OC) .. “are you on the Pill?”

• Warfarin (ask if, AF, CCF)

• Injections (INSULIN, EPO)

• Inhalers

• Eye drops (TIMOLOL)

• Patches (contraceptive implants, analgesia)

Drug History (Recent)

• Often cause of admission, so very, very important

• “Any changes to your tablets recently?”

• “New ones?”

• “One stopped? By whom? When? Why?”

• “Doses changed?”

• (Repeat) “Any other changes?”

Barriers to full Drug History (LO) • Patient

– Belief – physician has information (and we are all linked)

– Unfamiliar with medications and names

– Memory/Confusion (acute or chronic, or both)

– Language barrier

– Visual or hearing impairment

– Child/Elderly

– Old information

• Different locations (specialist units, different hospitals, psychiatry)

• Carer gives or sets up medication

• Bottles, blister packs or list unavailable

• ‘Difficult historian (you)’

Drug History Top Tips

• Balance open-ended questions (“tell me about your tablets”) with closed questions (eg requiring yes/no answers, eg “are you on the pill”?)

• Ask non-biased questions

• Avoid leading questions

• Explore vague responses (non-compliance)

• Avoid medical jargon (“ACE inhibitors”) – Keep it Simple

• Avoid judgmental comments, or colluding

Allergies

• “Are you allergic to any drugs?”

• “When and what happened when you took this medication?” (anaphylaxis)

• “Have you taken that medication since, and what happened?”

• “Are you allergic to anything else?” (repetition)

NB: Patients assume GPs + hospitals have agreed accessible place for allergy lists

Additional Questions to Explore Effectiveness/Compliance

• “Are any of your tablets causing side effects?”

• “Have you changed the dose or stopped any medication because of unwanted effects?”

• “Do you sometimes stop taking your medicine whenever you feel better?”

• “Do you sometimes stop taking your medicine if it makes you feel worse?”

Patient Education

• Encourage ownership

• Educate patient to bring medication (or list) from home at each appointment, admission (prescription and OTC)

• Encourage family members/ cares to become involved

• Encourage one pharmacy, one GP etc

Introduction to Prescribing

What is Prescribing?

• Prescribing is part of a logical process, based on comprehensive and objective information

• Key part of Western Medicine

• It is not a knee-jerk reflex, a recipe from a cook-book (swelling ≠ LASIX)

• Ie identify cause of swelling (CCF = furosemide)

• Never a response to commercial pressure

Write legibly (prescribing is not a joke)

P-drugs

• A physician should develop a standard treatment for common disorders, resulting in a set of first-choice drugs, called p(ersonal)-drugs

• You should know these drugs inside out

• Do not deviate, whatever reps tell you

Some of my ‘P-drugs’

Group Name Dose Alternative Monitor

ACEi Ramipril 2.5-10 mg od Lisinopril K, Urea, creat

ARB Losartan 25-100 mg od Candesartan K, urea, creat

B-blocker Bisoprolol 2.5-10 mg od Atenolol Pulse rate

Loop diuretic Furosemide 40-250 mg od Bumetanide Na, K

Thiazide diuretic

Bendroflumeth-azide

2.5-5 mg od Hydrochlorothi-azide

Na, K

HMG-CoA Atorvastatin 10-80 mg od Simvastatin Muscle pain, CK

Basic Rules• All in front of BNF

• CAPITALS

• Generic (‘chocolate’) not trade name (not ‘Cadburys’)

• Black or blue pen

• Date (with year)

• Dose, frequency

• Duration (if necessary)

• ‘Name, rank, number’

• Clear signature (PRINT if necessary)

• Legible

Dose (1)

• Biggest cause of problems

• Know simple doses, ie why I prefer LOSARTAN 25-100 mg, rather

• And .. avoid combination drugs

Dose (2): Problems start

• Grams (g)

• Milligrams (mg) .. easy to confuse with ..

• Micrograms (DIGOXIN 0.25 mcg) vs mcg vs μcg

• Picograms (DIGOXIN 250 pcg)

• Answer (BNF): write ‘micrograms’ below the dose

• Eg ‘6

micrograms’

If you have to break open 40 bottles, “Houston .. We have a problem”

Drugs Written as Units

• Eg insulin, heparin

• Common cause of (sometimes) major problems (hypoglycaemia, bleeding)

• As ‘u’ can be confused as a ‘0’ increasing the dose 10 fold

• Answer (BNF): (like micrograms) write the word ‘unit’ under the dose

• Eg ‘6

units’

Frequency

• OD (1x day)

• BD (2x)

• TDS (3x)

• QDS (4x)

• If cannot remember Latin, keep it simple, eg 1x per day etc

• Beware odd frequencies, eg weekly

Duration

• 5/7 = 5 days (good default short course)

• 2/52 = 2 weeks

• 1/12 = 1 month

• But do patients understand ‘5/7’?

Mode

• PO = oral

• IV = intravenous (not ‘stronger’ than oral)

• IM = intramuscular

• SC = subcutaneous

• Other ..

Speed of Effect

Side-effects

• Hard one

• Use BNF

• But .. the big BUT

• Know (and warn patient, preferably in writing) if:

• > 1%

• Serious, or serious to them (eg ciclosporin)

Inpatient: are drugs being given?

• Yes, you have to check

• Why, would they not be

Monitor

• Is it working?

• Compliance

.. how can you do that

Admendments to Standard Dosages (LO): Interactions)

• Very complicated

• Eg SIMVASTATIN 40 mg (20 mg if on VERAPAMIL/DILTIAZEM)

• Look them up

Admendments (LO): Elderly and Children

• Be careful

• If in doubt reduce dose and/or frequency

• Ask a senior

Admendments (LO):Renal, liver failure etc

• Many drugs are excreted by the kidney (eg digoxin) or liver so dose (esp maintenance) has to be reduced

• Other drugs are toxic to the kidney (aminoglycosides) or liver, so should be avoided, or used with caution

• Golden rule: if patient has renal or liver failure .. look it up

Admentments (LO):Pregnancy (two people)

• Its complicated

• Do not do it

• Ask someone more senior

Advice re how to look after medication

Stopping or changing dose of drug

• Just as dangerous as starting

• Who you are

• When

• Why stopping or changing

Don’t be afraid. Do something

• With all these ‘do’s and don’t’s, can be frightened to do anything

• If patient is unwell, do something

• Ask a senior, esp in F1/2 years

• Prescribing can be very therapeutic to you (eg furosemide in acute heart failure)

‘Where there is pus, let it out’

• Do you need to consider– Surgical option

– Radiological therapeutic option

• Don’t use prescribing to ‘treat a CRP’

• What is the cause of the raised CRP?

• Appendicectomy story ..

Factors that Influence Prescribing (LO)

• Knowledge

• Experience

• BNF and Local Formulary (next)

• Pharmaceutical industry (no)

• Cost (yes, esp GP)

• P-drugs

BNF and Local Formulary (LO)

• BNF says what can be prescribed in UK

• Licensed uses

• Local formulary (by Trust) will say what is recommended (should link to local guidelines)

• Look at via UHCW intranet (local one is within it)

• SWFT, George Eliot Hospitals, GPs and Psychiatry may have different formulary

• Look at Lothian, Wolverhampton formularies

BNF: Limitations (LO)

• Side-effects (what to mention to patient, first ever)

• Interactions (first ever)

• Cost

• More info: Manufacturer’s Summary Product Characteristics (SPC) via Google

BNF – ‘Yellow Forms’

• Side-effect profiles, interactions

• Would not exist without these .. and you

Cost of Drugs (£12bn pa?)

• Is your responsibility

• But in early years think more re efficacy, and not making mistakes

• High cost drugs

Cost of NHS

Cost of NHS Per Person Per Year

BNF - Demonstration

Quiz

Quiz

• First drug chart: list ‘good’ things (and a couple less good)

• Second drug chart: list ‘poor’ things

Buy a Book

Use the Internet

• http://www.uhs.nhs.uk/Media/suhtideal/Doctors/SaferPrescribingWorkbook/Section1-Prescriptionwriting.pdf

Summary

• Drug history is a very important skill

• Prescribing is a central tenet of Western Medicine

• BNF and local formulary should be part of your daily life as a doctor

• “A good doctor (physician, surgeon, GP, psychiatrist etc) is a good pharmacologist (and more importantly) clinical prescriber”

Thankyou

andrew.stein@uhcw.nhs.uk