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Prescribing Medications and
Drug Charts
More Fun than a Night in the Union
Introduction
Prescribing drugs is potentially one of the most
hazardous areas for PRHOs (and patients!). Write
up a wrong drug, wrong dose or incorrect route of
administration and the effects can be lethal. Many
of you will be confident prescribing drugs on a
chart but it never hurts to refresh and practice
these skills
This module will direct your learning but it is up
to you to put the knowledge and skills into
practice.
You will need the charts from
your pack and a BNF.
Aims and Objectives
This module is designed to direct your learning around the
knowledge and skills associated with prescribing
medications on a drug chart
By the end of this module students should
• Be familiar with and able to use the different components
of a drug chart
• Be able to change routes, doses and discontinue
medications on the chart
• Be more confident in their prescribing of common
medications on the drug chart
• Be able to calculate doses of intravenous and other
injections
An Apology and a Justification
I apologise most humbly to all of you who think this introductory
section is patronising and insulting. However in my ten+ years
experience teaching finalists I am continually dumbfounded (hence the
silly grin) by a small percentage of students who have obviously never
seen a drug chart or written up a set of medications. If you feel
confident that this is NOT you – please feel free to pass onto the
prescribing exercises. If you are unsure or in fact positive that I am
talking about you – then just sneak a look at the following few slides
‘as a refresher’ so to speak. What is important is that you will get this
correct in any assessment over the coming year, on day one of your
PRHO job and forever more!
TO COMPLETE THE FOLLOWING SECTIONS YOU WILL
NEED:THE DRUG CHART AND PHOTOCOPIED COMPONENTS
FROM YOUR FOLDER
A BNF
Challenge to Knowledge
(1)
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The following are all commonly prescribed by their trade names by PRHOs – what
are their generic names?
Atrovent
Maxalon
Stemetil
Augmentin
Parvolex
Gaviscon
Insulatard
Actonel weekly
Burinex K
Co- Amilofruse
Remember – what you write on the charts is your responsibility! If you have never
heard of a preparation or trade name – Don’t just blindly prescribe it - look it up in
the BNF.
(2) List three drugs you would commonly see, written on
(a) the once only and (b) the prn parts of the chart
(3) Write up a five day course of cephalexin po using the drug chart provided
Components of the Drug Chart
Do
not
adjust
your
eyes –
these
are all
out of
focus!
The Front Page
•Essential to fill in all the
patient details on the front
•Take a moment to read the
front page – it will tell you
how to
-discontinue medications and
the drug chart
-duty of care when
prescribing.
Doctor, Doctor – sometimes I think I’m a wigwam and sometimes I think
I’m a Teepee; I’m sorry but you’re two tents (too tense – hoho)
Please note - The correct answers are not provided
in this module – it is designed to help you learn
some prescribing skills and therapeutics. You
should practice these skills on all your firms by
offering to write and re-write the charts, noting
where and how medications are prescribed, altered
and discontinued. You should get your versions
checked by a friendly PRHO or SHO. The
answers should be include in your folder.
The Once Only Component –
‘Matron I was once a weak man; Doctor, Once a week is
enough for any man!’
Usually found on the inside
page of the chart
Used to write ‘Carter’s’
favourite ‘Stat’ dose of
anything E.g.
•First dose of an antibiotic
•One off dose of analgesia or
hypnotic
•Stat dose of heparin or
insulin
My auntie Marge (hold that name), My auntie Marge,
she’s been so unwell for so long now we can’t believe
she’s not better ……(please yourselves!)
A 79 yo woman is admitted to hospital with
septic shock and HONK. You are asked to
prescribe her a stat dose of cefuroxime 750
mg IV, gentamicin 160 mg IV and clexane
40mg sc.
Please write up the medications on the
appropriate part of the chart (photocopy)
‘The regular side’
•Does what it says on the
tin
•Component for
prescribing all regular
medications
•Medications may be
continued in this section
following a stat dose e.g.
the cefuroxime from the
last example
•Patient’s regular
medications are also
written in this section
For each of the following scenarios write up the patient’s regular
medications on the charts provided. Any medication that you are uncertain
of its side effects or actions please annotate your prescription using the BNF
(a)
Cefuroxime 750mg IV tds, Metronidazole 1g PR bd, Salbutamol nebulisers 2.5mg
qds
(b)
Metoprolol 50mg po tds, aspirin 75 mg po od, clopidogrel 75mg po od, clexane
70mg sc bd, lansoprazole 30mg po od, atorvastatin 40 mg po od
(c)
Mixtard 30/70 insulin sc 24 units am, 16 units pm; ramipril 5mg po od, pravastatin
20mg po od, frusemide IV 80mg mane, 40mg noon
(d)
Prednisolone 20mg po od, Risedronate 35mg po once per week; Adcal D3 one tablet
po bd; ciprofloxacin 500mg po bd
(e)
Spironolcatone 200mg po od, thiamine 200mg po od, pabronex 1 vial IV bd for
three doses only; multivitamins one tablet po od, flucloxacillin 500mg po qds for 5/7
(f)
Lansoprazole 30mg po bd, amoxycillin 1g po bd and clarithromycin 500mg po bd
The ‘As Required’ or PRN component.
Doctor, Doctor I’ve got a really sore throat, Little hoarse? Neigh!, Little
raw? Raaaah!
Often sited on the same page
as the once only section but not
in this case!
Used to write up medications
which may be required from
‘time to time’
E.g. Anti-emetics
Analgesia
GTN
Nebulisers
Antacids
Laxatives are commonly written here
but should be written regularly to have
a good effect
What’s the worst thing about having a lung transplant?
Coughing up someone else’s sputum!
An 85 yo man is admitted to hospital with
ACS. Overnight he becomes agitated and
confused and is written up for PRN
haloperidol along with the ‘usual’ PRN
medications for ACS.
Please write up the PRN medications on the
chart provided.
Anticoagulation with Warfarin
from where we get the verb ‘to Warfarinise’
•Most hospital charts now
incorporate a section for
anticoagulation with warfarin.
•The chart opposite also includes a
modified Fennerty dosing regime
– so makes your life very easy!
•Warfarin dosing is important as
get it wrong and under and over
anticoagulation may have serious
consequences.
•You all need to be familiar with
warfarin and its interactions – see
next few slides
WARFARIN
• List three indications for Warfarin therapy
• List the essential steps before discharging a patient on
Warfarin
Prescribing Exercises
• Write up a loading regime for a 41yo woman who has just had
a left Lower limb DVT confirmed on ultrasound scan. She is
otherwise well and is on no regular medication.
• A 61 yo man who is on long term warfarin treatment presents
in A&E with a ‘torrential’ epistaxis. He is haemodynamically
stable but his INR is 9.9. What is your management? Write up
the prescribed medications on the chart.
Warfarin
• Coumarin anticoagulant
• Indications
- Arterial and Venous thrombo –embolic disease and
prophylaxis
• Main side effect – Haemorrhage
• Therapeutic levels based on INR
INR 2 – 3: DVT, PE, AF, Arterial thrombosis
INR 3 – 4: Metallic heart valve
• All patients should be referred to and managed by specialist
anticoagulation service; Given a anticoagulation booklet
before discharge.
Drug Interactions With Warfarin
Drugs that Increase INR – Drugs that Decrease INR
Increase effect
– Reduce effect
NSAIDs
Omeprazole / Cimetidine
Macrolides
Ciprofloxacin
Alcohol excess
Carbamazepine
Phenytoin
Rifampicin
Flu/Ketoconazole
Isoniazid
Trimethoprim
Oral Contraceptives
Griseofulvin
Amiodarone / verapamil
aRetrovirals
Fennerty nomogram
Fennerty A, Thomas P, Backhouse G, Bentley DP, Campbell IA, Routledge PA. Flexible induction dose
regimen for warfarin and prediction of maintenance dose. Br Med J 1984; 288:1268-70.
This protocol is designed to
• achieve a target INR of 2 to 3 relatively quickly
• reducing the risk of overanticoagulation which is more
likely to occur in patients who exhibit greater sensitivity to
warfarin (eg older patients, patients with liver disease,
inadequate nutrition, or CHF).
However: it does not eliminate INR overswings entirely, and
a lower loading dose of 5mg may be used in patients
thought to be especially at risk.
Warfarin Dosing - II
Day
1st
2nd
3rd
INR
< 1.4
< 1.8
1.8
> 1.8
<2.0
2.0-2.1
2.2-2.3
2.4-2.5
2.6-2.7
2.8-2.9
3.0-3.1
3.2-3.3
3.4
3.5
3.6-4.0
>4.0
Warfarin dose (mg)
10
10
1.0
0.5
10
5
4.5
4
3.5
3
2.5
2
1.5
1.0
0.5
0
Predicted maintenance dose: 4th Day
INR
Warfarin (mg)
<1.4
>8
1.4
8
1.5
7.5
1.6-1.7
7
1.8
6.5
1.9
6
2.0-2.1
5.5
2.2-2.3
5
2.4-2.6
4.5
2.7-3.0
4
3.1-3.5
3.5
3.6-4.0
3
4.1-4.5 Miss out next day's
dose, then give 2 mg
>4.5Miss out 2 days' doses
then give 1 mg
Bleeding Hell!
•
Major bleeding—stop warfarin; give vitamin K1 - 5 mg by slow intravenous
injection; give prothrombin complex concentrate (factors II, VII, IX and X)
50 units/kg or (if no concentrate available) fresh frozen plasma 15 mL/kg
•
INR > 8.0, no bleeding or minor bleeding—stop warfarin, restart when INR < 5.0;
if there are other risk factors for bleeding give vitamin K1 0.5 mg by slow
intravenous injection or 5 mg by mouth (for partial reversal of anticoagulation give
smaller oral doses of vitamin K e.g. 0.5–2.5 mg using the intravenous preparation
orally); repeat dose of vitammin K if INR still too high after 24 hours
•
INR 6.0–8.0, no bleeding or minor bleeding—stop warfarin, restart when INR < 5.0
•
INR < 6.0 but more than 0.5 units above target value—reduce dose or stop
warfarin, restart when INR < 5.0
•
Unexpected bleeding at therapeutic levels—always investigate possibility of
underlying cause e.g. unsuspected renal or gastro-intestinal tract pathology
Changing from one route of
administration (+/- dose) to another
(1)
(2)
(3)
(4)
(5)
(6)
Please change the route of administration and
the dose (when required) of
IV to PO cefuroxime
Nebulised to inhaled salbutamol
IV to PO metronidazole
IV to PO metoclopramide
IV to PO Flucloxacillin
IV Benzylpenicillin to PO Penicillin V
This what they should look like
Up close and personal
Note:
•Cross through of the
previous dose and
ROA
•Discontinuation of
Benzylpenicillin
•Period of
administration limited
by ‘gating’
(see Penicillin V)
•You only need to rewrite the whole
prescription if you
change the name of
the drug
Discontinuing and Gating the period of administration
• To discontinue a drug simply cross through the
doses, the signed area and place a vertical line
with signature at the end of the signed doses (as
shown above).
• To limit the administration period you can ‘gate’
the period of time with horizontal lines (as
shown). This stops drugs being given for
inappropriate lengths of time or before they are
due to start. This is very important to limit the
potential for prolonged admissions and the risk of
hospital acquired infection
Using the drug charts provided write up medications for each
of the patients below. The management is entirely up to you
but any drugs you are unfamiliar with you should annotate the
chart from the BNF.
(1)
A 63 year old man is admitted with an acute infective exacerbation of
COPD. Cultures grow Haemophilus Influenzae.
(2)
A 71 year old woman is admitted to CCU with an acute anterior MI. Her
cholesterol is 7.4 mmol/l, Random Glucose 12.6 mmol/l and BP 130/70.
She is given thrombolysis and a stat dose of frusemide in A&E.
(3)
A 48 year old man with Type 2 DM is admitted to hospital with an infected
foot ulcer. He is on QDS insulin and several anti-hypertensives including an
ACEI and a thiazide diuretic.
(4)
A 41 year old woman is admitted under the surgoens with acute abdominal
pain, localised in the right upper quadrant. Her blood cultures grow gram
negative rods.
Learning Outcomes
At this point you should
• Be able to use all components of the drug chart appropriately
• Be more confident writing up common medications on ward rounds
and on re-writes (You will need to get a qualified doctor to sign for
them)
• Be able to discontinue and limit prescriptions of medications
If you are unable to achieve all of these outcomes at this point
you will need to continue to practice the skills and re-visit
the webpages to refresh your knowledge
All photocopied pages should be placed in your PPD folders.
They will not be formally assessed but they WILL be
appraised to ensure you have completed these sections.
Failure to do so will mean your entry into the final MBBS
examinations may be delayed.