PRESCRIBING FOR THE

PSA AND FINALS

DR FRANCESCA BONORA

WHAT WE WILL COVER

• HOW TO PREPARE FOR THE PSA EXAM

• HOW SCENARIOS APPLY TO PRESCRIBING FOR FINALS

THE PSA EXAM

For full details of what could be asked:

prescribingsafetyassessment.ac.uk/aboutpsa

Click on PSA blueprint for November 2017 PDF

EXAMPLES OF ITEM STYLES

SECTION 1 – PRESCRIBING

• Decide on the most appropriate prescription (drug,

dose, route and frequency), based on the clinical

circumstances

• Write a safe, effective and legal prescription

• 8 questions worth 10 marks each

• Make sure you sign the prescriptions with

your full surname (not initials) – don’t lose

the easy marks

HOW TO PREPARE

• Exam is time pressured, so LEARN TREATMENT

ALGORITHMS:

• Acute conditions eg acute asthma attack, acute heart

failure

• Chronic conditions e.g. depression, reflux oesophagitis

• Presenting symptoms e.g. pain

• Find these in the back of the Oxford handbook

OXFORD HANDBOOK ALGORITHMS

THIS BOOK IS GREAT

PASS THE PSA, 1E, FEB 2014,

BY WILL BROWN BSC MBBS MRCP(UK) FHEA AND KEVIN W LOUDON

TREATMENT ALGORTIHMS

ANAPHYLAXIS

ACUTE ASTHMA

MAKE THESE FOR YOURSELF FOR ALL COMMONEST ACUTE AND

CHRONIC MEDICAL CONDITIONS

PASS THE PSA, 1E, FEB 2014,

BY WILL BROWN BSC MBBS MRCP(UK) FHEA AND KEVIN W LOUDON

HOW TO PREPARE

• If you can’t remember – use treatment summaries in the

online BNF during the exam

• CTRL + F is your best friend!

BNF TREATMENT SUMMARIES

CTRL + F

PRESCRIBING CONTROLLED DRUGS – WHICH IS CORRECT?

MORPHINE SULPHATE 10mg oral tabletsTake one tablet, three times dailyPlease supply 28 (TWENTY-EIGHT) tablets.

MORPHINE SULPHATE 10mg oral tabletsTake one tablet, three times daily.Please supply 28 10mg(TEN MILLIGRAM) tablets.

29 Andrew Smith

01/10/87 Perrin Lecture Theatre

29 Andrew Smith

01/10/87 Perrin Lecture Theatre

PRESCRIBING CONTROLLED DRUGS – WHICH IS CORRECT?

MORPHINE SULPHATE 10mg oral tabletsTake one tablet, three times dailyPlease supply 28 (TWENTY-EIGHT) tablets.

MORPHINE SULPHATE 10mg oral tabletsTake one tablet, three times daily.Please supply 28 10mg (TEN MILLIGRAM) tablets.

It’s the ‘total amount’ that you

need to specify

29 Andrew Smith

01/10/87 Perrin Lecture Theatre

29 Andrew Smith

01/10/87 Perrin Lecture Theatre

PRESCRIBING CONTROLLED DRUGS

• Include the name and address of the patient.

• State the name and strength of the drug

• State the dose and frequency

• TOTAL AMOUNT must be written in WORDS AND FIGURES

WHAT DOSE SHOULD YOU PRESCRIBE?

WHAT DOSE SHOULD YOU PRESCRIBE?

SECTION 2 – PRESCRIPTION REVIEW

• Identify prescriptions (drugs, doses or routes) that are

inappropriate, unsafe or ineffective from amongst the

current list of prescribed medicines

• 8 items worth 4 marks each

PRESCRIPTION REVIEW

FUROSEMIDE

PREDNISOLONE11/1/17

PO

11/1/17PO

40mg

40mg

PRESCRIPTION REVIEW

FUROSEMIDE

PREDNISOLONE11/1/17

PO

11/1/17PO

40mg

40mg

SHOULD BE GIVEN IN MORNING – WILL KEEP PATIENT AWAKE!

SHOULD BE GIVEN IN MORNING – WILL KEEP PATIENT AWAKE!

SPOT THE MISTAKES

SPOT THE MISTAKES

INCORRECT DOSE – SHOULD BE 62.5 MICROGRAMS

WRITE UNITS (NOT JUST ‘U’) – TECHNICALLY SHOULD BE

PRESCRIBED ON THE INSULIN AREA OF THE CHART!

WRITE “MICROGRAMS” IN FULL

WHAT TYPE?

FLUID CHART ERRORS

11/1/17 0.9% Saline 1 litre KCl 40mmol STAT A.L.S

11/1/17 Red Blood Cells 2 units ----------------- 4 hours A.L.S

11/1/17 50% Dextrose 1 litre 12 hours A.L.S

FLUID CHART ERRORS

11/1/17 0.9% Saline 1 litre KCl 40mmol STAT A.L.S

11/1/17 Red Blood Cells 2 units ----------------- 4 hours A.L.S

11/1/17 50% Dextrose 1 litre 12 hours A.L.S

This amount of potassium must be given over at least 4 hours due to risk of arrhythmias

Each unit needs to be prescribed

separately

Has to be discarded 4 hours

(from leaving the lab)

50% Dextrose is irritant to veins. It should only be

given in small volumes (20% should preferably be

used if trying to reverse hypoglycaemia)

SECTION 3 – PLANNING MANAGEMENT

• Deciding which treatment would be most appropriate to

manage a particular clinical situation

• 8 items worth 2 marks each

• Choose most appropriate treatment from list of 5

COMMON ACUTE CONDITIONS

KNOW THE TREATMENT ALGORITHMS FOR:

• STEMI

• NSTEMI

• ACUTE LEFT VENTRICULAR FAILURE

• TACHYCARDIA WITH PULSE

• ANAPHYLAXIS

• ACUTE ASTHMA EXACERBATION

• PNEUMONIA

• PE

• GI BLEED

• BACTERIAL MENINGITIS

• SEIZURE

• STATUS EPILEPTICUS

• STROKE

• HYPERGLYCEMIA

• DKA AND HHS

• AKI

• POISONING

COMMON CHRONIC CONDITIONS

KNOW THE TREATMENT ALGORITHMS FOR:

• HYPERTENSION • CHRONIC HEART FAILURE • STROKE PREVENTION

• STABLE ANGINA • CHRONIC ASTHMA • COPD• DIABETES • INSOMNIA • CONSTIPATION• DIARRHOEA • PAIN

SECTION 4 – PROVIDING INFORMATION

• Decide the most important piece of information that

should be provided to patients to allow them to choose

whether to take the medicine and to enhance its safety

and effectiveness

• Six items worth 2 marks

PROVIDING INFORMATION

DRUG INFORMATION

RAMIPRIL STOP IN PREGNANCY – TERATOGENIC

GLICLAZIDE EAT REGULARLY, DON’T SKIP MEALS – HYPO RISK

METHOTREXATE REGULAR FBC – NEUTROPENIA RISK

WARFARIN MONITOR INR - BLEEDING

LONG TERM STEROIDS TAKE BISPHOSPHONATE – OSTEOPEROSIS RISK

DON’T STOP SUDDENLY

SSRI CONTACT DOCTOR IF THOUGHT OF SELF HARM

INSULIN DOSE MAY NEED TO BE INCREASED IF UNWELL

BISPHOSPHONATE TAKE WITH FULL GLASS OF WATER AND REMAIN UPRIGHT

FOR 1 HOUR

SECTION 5 – CALCULATION SKILLS

• Making an accurate drug dosage calculation based on

numerical information

• Recording answer accurately with appropriate units of

measurement

• 8 items worth 2 marks

MAKE SURE YOU PRACTICE

• Correct number of tablets to achieve a required dose

• Making necessary dose adjustments based on weight or

body surface area

• Diluting a drug for administration in an infusion pump

DRUG RATIOS

1% means

• 1g in 100ml or 10mg in 1ml for weight/volume (w/v)

calculations

• 1g in 100g for weight/weight calculations

ADRENALINE RATIOS

• ANAPHYLAXIS

• 0.5mg = 0.5ml of 1 in 1,000 IM

• Remember 1 in 1,000 means: 1g in 1000 ml or 1000mg in 1000ml or 1ml in 1mg

• Therefore 0.5ml = 0.5mg

• CARDIAC ARREST

• 1mg = 10ml of 1 in 10,000 IV

• Remember 1 in 10,000 means: 1g in 10,000 ml or 1,000mg in 10,000ml or 1mg in 10ml

Dosage Calculations

Always convert to the same units and then:

D (What you want) x V (volume it is in) = Dose

H (What you’ve got)

Try some practice questions:http://www.drugs.smd.qmul.ac.uk/drugs/html5/Prescribing5/AN-781CE9AF-87B9-F0E4-01F9-205B0DCC08BA.html

https://www.abdn.ac.uk/medical/electives/elective_information/.../PSA_Tutorial.pdf

SECTION 6 – ADVERSE DRUG REACTIONS

• Likely adverse reactions to specific drugs, potentially

dangerous interactions, managing adverse effects of a

drug

• 8 items worth 2 marks each

ADVERSE DRUG REACTIONS

‘THE CTRL + F SECTION’

• Adverse effects caused by commonly prescribed drugs such as calcium channel blockers, beta2-agonists, non-steroidal anti-inflammatory drugs, aminoglycoside antibiotics, etc.

• Most likely drug to have caused adverse effect e.g. renal impairment, hepatic dysfunction, hypokalaemia, urinary retention, etc.

• Potential interactions between medicines e.g. warfarin-statins, NSAIDs-ACE inhibitors

• How to treat an adverse drug reaction e.g. acute anaphylaxis, excessive anticoagulation, drug-induced hypoglycaemia, diuretic-induced dehydration etc.

SPOT THE POTENTIAL ADVERSE EFFECT

SPOT THE POTENTIAL ADVERSE EFFECT

POTASSIUM – BOTH DRUGS CAN CAUSE HYPERKALAEMIA

SPOT THE POTENTIAL ADVERSE EFFECT

POTASSIUM – BOTH DRUGS CAN CAUSE HYPERKALAEMIA

Some drugs causing HYPERKALAEMIA

• ACE Inhibitors

• Angiotensin Receptor Blockers (ARB)

• Beta Blockers

• Digoxin

• Heparin

• NSAIDs

• Spironolactone

• Transfusions of RBC

• Trimethoprim

WHAT IS THIS PATIENT AT RISK OF ?

WHAT IS THIS PATIENT AT RISK OF ?

PHENYTOIN TOXICITY

Enzyme inhibitor

Enzyme inducer(but relatively less so)

ENZYME INHIBITORS AND INDUCERS

INDUCERS INHIBITORS

Increase enzyme activity

Reduce drug concentration

Reduce enzyme activity

Increase drug concentration

PC BRASPhenytoin

Carbamazepine

Barbituates

Rifampicin

Alcohol (chronic excess)

Sulphonylureas

AODEVICESAllopurinol

Omeprazole

Disulfiram

Erythromycin

Valproate

Isoniazid

Ciprofloxacin

Ethanol (acute itntoxication)

Sulphonamides

WHAT IS THIS PATIENT AT RISK OF ?

OMEPRAZOLE

PAROXETINE11/1/17

PO

11/1/17PO

20mg

40mg

WHAT IS THIS PATIENT AT RISK OF ?

OMEPRAZOLE

PAROXETINE11/1/17

PO

11/1/17PO

20mg

40mg

Drugs commonly causing

HYPONATRAEMIA

• Thiazide diuretics

• Amiloride

• Carbamazepine

• Sulphonylureas (but not Gliclazide)

• Proton pump inhibitors

• Antidepressants, particularly SSRIs

• ACE inhibitors and ARBs

• Opiates

NEPHROTOXIC & HEPATOTOXIC DRUGS

NEPHROTOXIC HEPATOTOXIC

ACE Inhibitors

Aminoglycosides

NSAIDs

Methotrexate

Amiodarone

Isoniazid

Co-amoxiclav

NSAIDs

Statins

Anti-fungals

Anti-retrovirals

PENICILLIN ALLERGY

AVOID CAUTION SAFE

FLUCLOXACILLIN

TAZOCIN

CO-AMOXICLAV

CEFTRIAXONEMEROPENEM

AMIKACIN

METRONIDAZOLE

ERYTHROMYCIN

RIFAMPACIN

PENICILLIN ALLERGY

ALLERGIC REACTION MANAGEMENT

A patient recently given Tazocin despite a Type 1 Penicillin allergy develops shortness of breath, stridor and a widespread urticarial rash.

Choose 3 appropriate treatments:

A) Chlorphenamine 4mg, POB) Adrenaline 10ml of 1:10000, IVC) Adrenaline 10ml of 1:10000, IMD) Adrenaline 0.5ml of 1:1000, IVE) Adrenaline 0.5ml of 1:1000, IMF) Hydrocortisone 200mg, IVG) Chlorphenamine 10mg, IV

ALLERGIC REACTION MANAGEMENT

A patient recently given Tazocin despite a Type 1 Penicillin allergy develops shortness of breath, stridor and a widespread urticarial rash.

Choose 3 appropriate treatments:

A) Chlorphenamine 4mg, PO – only after resuscitationB) Adrenaline 10ml of 1:10000, IV – cardiac arrest, 1mgC) Adrenaline 10ml of 1:10000, IM – never usedD) Adrenaline 0.5ml of 1:1000, IV – never usedE) Adrenaline 0.5ml of 1:1000, IM – e.g. 0.5mgF) Hydrocortisone 200mg, IVG) Chlorphenamine 10mg, IV

SECTION 7 - DRUG MONITORING

• How to monitor the beneficial and harmful effects of

medicines.

• 8 items worth 2 marks

DRUG LEVEL MONITORING - EXAMPLES

Drug Half-life Timing Toxic Level* Major Toxic Effects

Gentamicin 2h TroughAfter 2-3

doses>2mcg/ml

Nephrotoxity, irreversible

ototoxicity

Phenytoin 20-40h TroughAfter 2-3

days

Total

>20mcg/ml

Free >2mcg/ml

Nystagmus, diplopia,

ataxia, confusion,

hyperglycaemia

Aminophylline4-16hr

N/A

4-6hrs after

starting IV

infusion >20mcg/mlArrhythmias, convulsions,

hypotension

Theophylline Trough 5 days

Digoxin 24-36h Trough 1 week >2ng/mlArrhythmias, visual

disturbance, anorexia

Some detail on specific drugs: http://tinyurl.com/druglevels

OTHER DRUG MONITORING

DRUG MONITOR

WARFARIN INR

LEVOTHYROXINE TFT (CHANGE DOSE EVERY 4 WEEKS)

ACE INHIBITORS / DIURETICS U&Es

CLOZAPINE FBC

ORAL CONTRACEPTION BLOOD PRESSURE

GENTAMICIN DOSINGHartford nomogram: guides when to give patient next dose, based on blood

concentration and the time the measurement was taken

E.g. if concentration is 8mg/ml, 8h after start of

infusion – what is correct dosing interval?

GENTAMICIN DOSINGHartford nomogram: guides when to give patient next dose, based on blood

concentration and the time the measurement was taken

Answer: 36h

SECTION 8 – DATA INTERPRETATION

• Make an appropriate change to a prescription based on

results of investigations

• 6 items worth 2 marks

PARACETAMOL OVERDOSEActivated charcoal: consider if >150mg/kg has been taken within

a 1 hour period.

N-acetylcysteine (NAC):

• Single overdose – check level at 4h and use the nomogram (use

nomogram when OD has been taken between 4-8h ago)

• If plasma concentration levels are above the treatment line then

you need to treat

• Staggered overdose (>1h) – cannot accurately calculate levels so

treat

PARACETAMOL OVERDOSE

E.g. Patient takes 10

paracetamol tablets at 09.00

Blood test taken at 13.00

Paracetamol concentration

0.4mmol/litre

PARACETAMOL OVERDOSE

DON’T TREAT

PRESCRIBING SCENARIOS FINALS

• All the same scenarios in different formats

• OSCES• Prescribe warfarin

• Prescribe an IM injection eg vitamin B12

• Spot the prescription errors

• Write fluid prescription and calculate drip rates

• Presenting a history and giving treatment recommendations eg hypertension

• WRITTEN PAPER• Know your treatment algorithms for acute and chronic conditions

• Data interpretation questions – remember side effects of drugs and how they can affect blood results

GOOD LUCK!!francescabonora@hotmail.com