Introduction to BNF and Prescribing

ICL – 3rd year medical students

•Aim

– To be able to navigate around the BNF

•Objectives– Summarise the information contained

within each of the sections within the BNF

– Demonstrate ability to retrieve information from the BNF

– Prescribe at least one drug on the Manchester Prescription Chart

Summarising BNF information

• Work with the person sitting next to you

• Activity 1 – Summarise the information in pages 0-42 (or

‘Preliminary’)

• Activity 2– Describe the information available in section 2 on

‘supraventricular & ventricular arrhythmias’

– Also the information under ‘amiodarone’

Summarising BNF information

• Work with the person sitting next to you

• Activity 3 – Summarise the information contained in appendix 1

(‘appendices’). Identify if there is an interaction between amiodarone & simvastatin by looking up both drugs PLUS

• Activity 4– Summarise the information in appendices 2-5. Tell the

group important information about infusing amiodarone

BNF Sections• Part 1

– Lots of useful information about prescribing and prescribing in certain conditions e.g. palliative care

• Part 2– Section 1-15 Individual drug monographs

• Appendix– Appendix 1 - Interactions– Appendix 2 - IV additives– Appendix 3 - Borderline substances– Appendix 4 - Wound management products &

elasticated garments

– Appendix 5 - Cautionary &advisory labels• Additional Information (back of BNF)

Completing theCompleting thePrescriptionPrescription• Patient details, NHS number

important as may have more than one patient of same name

• Ward and consultant• Allergies• Chart details • Drug by APPROVED name

(unless an exception)• Dose, use most approp.

Format e.g. 0.5mg write as 500 micrograms (not mcg)

• Route and review/stop date• Never abbreviate ‘units’ to ‘u’

1112223335

Bloggs

Joseph

25.4.65 75Kg

Dr Shields MAU

AMOXICILLIN

500mg IV 22/9

DO 24/9

D Octor TF S

1 1

22/9/10

NKDA

23/9/10

Nasal

24%

2L/min

COPD

DO

D Octor 5555

7/7CAP

• Indicate the frequency by ticking the times

• Always indicate a frequency on PRNs

• Don’t forget to indicate if controlled release

• Only use Latin abbreviations listed in BNF (avoid q.q.h. as often confused with q.d.s.)

• Always state a maximum in 24 hours

Completing theCompleting thePrescriptionPrescription

Bloggs Joe 1112223335 25.4.65

PARACETAMOL

1g PO 23/9

DO 28/9

D Octor TF S

DIHYDROCODEINE TFS

30mg PO

A Doc 29/3

Dr Doc PAIN

3 hourly

ISOSORBIDE Mononitrate

60mg PO 23/9

DO n/a

D Octor TF 23/9

Angina

M/R or X/L

240mg

Prescribing PracticePrescribing PracticeCase 1Case 1

• One of the nurses asks you, in passing, to prescribe some ‘PRN paracetamol’ for Amy. She is not on regular medications and has no allergies (the reason for admission is not a contraindication to paracetamol being prescribed)

Miss Amy Patient, DOB 12/7/72, NHS No. 2819735, Ward MAU, Consultant Sharma

Case 1 continued

• The patient has some tests done and a diagnosis of community-acquired pneumonia is made

• Your registrar asks you to prescribe ‘oral Augmentin’

• What further information would you need?

• What information sources would you use?

PARACETAMOL TFS

1g oral 4-6hrly D Octor 28/9 4g D Octor Pain

Don’t forget patient details at top of each page used

CO-AMOXICLAV 500/125

1 tablet oral 22/9

D Octor 25/9

D Octor TFS COMMUNITY ACQUIRED PNEUMONIA 7

days

Summary

You will have the opportunity to utilise these skills over the next 3 years.

.

BNF Questions

1. Your patient is taking warfarin. Is it safe to start

carbamazepine to treat this patient's poorly controlled epilepsy?

2. You have been asked to provide palliative care treatment for a patient with cancer. You need to increase the dose of the patient's morphine modified-release tablets to 120mg every 12 hours. What would be a suitable 4 hourly breakthrough dose of morphine sulphate oral solution?

3. A patient has deteriorating renal function, as indicated by his eGFR which is 17ml/minute/1.73m2. What dose of Tazocin should he be prescribed?

4. A doctor wishes to start a patient with liver impairment on an antidepressant. Is Cipralex safe to use?

5. The internet is not working so you cannot access Toxbase. Do you need to prescribe anything for a patient who took a paracetamol overdose 9 hours ago and has a level of 60mg/L? They are not taking any other medications and are generally healthy.

Answers

1.Your patient is taking warfarin. Is it safe to start carbamazepine to treat this patient's poorly controlled epilepsy?

Appendix 1 - Interactions

Metabolism of coumarins accelerated by carbamazepine therefore INR can be reduced.

 

2.You have been asked to provide palliative care treatment for a patient with cancer. You need to increase the dose of the patient's morphine modified-release tablets to 120mg every 12 hours. What would be a suitable 4 hourly breakthrough dose of morphine sulphate oral solution?

Prescribing in Palliative Care- under subheading ‘Pain management with opioids’

Breakthrough pain is one-tenth to one-sixth of 24 hour total daily dose every 2-4 hours when required. Total daily dose for this patient is 120mg x 2 = 240mg. Therefore breakthrough dose is 24mg-40mg depending on clinical assessment of need.

 

3.A patient has deteriorating renal function, as indicated by his eGFR which is 17ml/minute/1.73m2. What dose of Tazocin should he be prescribed?

Piperacillin with tazobactam monograph – under subheading ‘Renal Impairment

Maximum dose = 4.5g every 12 hours.

Answers

4.A doctor wishes to start a patient with liver impairment on an antidepressant. Is Cipralex safe to use?

Escitalopram monograph – under subheading ‘Hepatic Impairment’

Initial dose of 5mg daily for two weeks increasing thereafter to 10mg daily according to response and LFTs. Particular care should be taken in severe impairment.

 

5. The internet is not working so you cannot access Toxbase. Do you need to prescribe anything for a patient who took a paracetamol overdose 9 hours ago and has a level of 60mg/L? They are not taking any other medications and are generally healthy.

Emergency treatment of poisoning section – under subheading ‘Analgesics – Paracetamol’

Using the graph – treatment is not necessary as serum level is below the treatment line.