1. An Introduction to Prescribing Narinder Bhalla Lead Pharmacist – Clinical Governance Addenbrooke’s NHS Trust November 2006

2. Objectives  What is prescribing?  Responsibilities of the prescriber  Good prescribing principles  Using the BNF and other info sources  Principles of prescribing in special groups

3. When it goes wrong

4. What is prescribing  Writing/generation of a prescription for a drug (paper or electronic).  Verbal order for a drug to be administered on doctor’s advice.

5. Responsibilities of the prescriber  If you prescribe a drug you are clinically and legally responsible for your actions.  If you are asked to prescribe the drug, it is the person who signs the prescription who is responsible

6. n Right Patient n Right Drug n Right Dose n Right Route n Right Time Responsibilities of the prescriber

7.  Only prescribe medicines that you are competent to prescribe. (knowledge of drug indication, action, dosing, side-effects, interactions). (knowledge of drug indication, action, dosing, side-effects, interactions).  Only prescribe medicines if they are necessary  Prescribe only if benefits of medication outweigh the risks  Discuss treatment options with the patients/concordance  Indicate likely/degree of benefit (efficacy), onset and duration  Discuss side-effects/tolerability

8. Concordance (www.medicinespartnership.org)  The prescriber and the patient should agree on the health outcomes and the strategy for achieving them.  Consider religious, cultural and personal beliefs that may affect acceptance of medicines.  Keep drug regimes simple and review regularly  Combination treatments only if benefits outweigh risks (restrict ability to titrate doses).

9. Principles of Good Prescribing  State patient details clearly (name, address, date of birth, age (children/elderly).  Take account of any allergies and complete relevant paperwork.  Use generic drug names  State drug, dose, strength, route and frequency  Avoid abbreviations  Avoid multiple route prescribing (i.e. im/sc/po)  State dose as grams, mg, mcg.  Make administration of once weekly drugs clear

10. Generic Prescribing  Prescribe by the approved drug name  Ensures clarity regarding drug required  Ensures that the most-cost effective version of the drug can be supplied.

11. Commonly Used latin abbreviations ac.- ante cibum (before food) bd.- bis die (twice daily) od.- omne die (once daily) om.- -omni mane (every morning) on.- omni nocte (every night) tds- ter die sumendus (to be taken three times daily tid- ter in die (three times daily) pc.- post cibum (after food) prn- pro re nata (when required) qds- quarter die sumendus (to be taken four times daily times daily

12. Types of prescription  FP10 (white) Standard NHS prescription issued by GPs that can be dispensed by a pharmacy registered to dispense NHS prescriptions  FP10(HP) Yellow NHS prescription issued by hospitals, that can be dispensed by a registered pharmacy.  FP10P Nurse prescriber’s NHS prescriptions that can be dispensed by a registered pharmacy.

13. Types of prescription  Hospital prescriptions Outpatient clinic prescriptions Main drug chart Anticoagulant chart Diabetic chart IV chart

14. Factors affecting prescribing  Patient’s clinical state  Concomitant disease  Severity of current disease  Available treatments (consider likely outcomes (patient oriented outcomes)/quality of life). (consider likely outcomes (patient oriented outcomes)/quality of life).  Likely efficacy of treatments  Side-effects/tolerability  Interactions (drugs and food)  Compliance/health benefits

15. British National Formulary (BNF) www.bnf.org  Front section  Prescribing guidance, prescription writing & CD prescribing  Prescribing in children, elderly & palliative care  Emergency treatment of poisoning Middle section  Approved Drug Name with indications, S/E, cautions & dose Back section  Appendixes: interaction, pregnancy  Abbreviations used in the BNF (BNF Back page)

16. BNF (www.bnf.org) The main text consists of classified notes on clinical conditions, drugs and preparations. These notes are divided into 15 chapters, each of which is related to a particular system of the body or to an aspect of medical care. Chapter 1: Gastrointestinal system Chapter 2: Cardiovascular system Chapter 3: Respiratory system Chapter 4: Central Nervous System Chapter 5: Infections Chapter 6: Endocrine system Chatper 7: Obs and Gynae and Urinary tract disorders Chapter 8: Malignant disease and immunosuppression Chapter 9: Nutrition and blood Chapter 10: Musculoskeletal and joint disorders Chapter 11: Eye Chapter 12: ENT Chapter 13: Skin Chapter 14: immunological products and vaccines Chapter 15: Anaesthesia

18. Drug listings in the BNF Drug Name Indications: (details of use and indications) Cautions: details of precautions required (with cross-references to appropriate Appendixes) and also any monitoring required. Contra-indications: details of any contra- indications to use of the drug. Side-effects: details of common and more serious side-effects. Dose: dose and frequency of administration (max dose); Child and Elderly details of dose for specific age group. By alternative route, dose and frequency. Approved name: form, pack size and price. Proprietary name: form, pack size and price.

19. BNF Appendixes Appendix 1-Drug Interactions  A black dot symbol is placed against those interactions that are potentially hazardous.  Interactions listed by drug/drug class in alphabetical order.

20. BNF Appendixes Appendix 2  Table of drugs to be avoided or used with caution in liver disease Appendix 3  Principles of dose adjustment in renal impairment  GFR values  Table of drugs to be avoided or used with caution in renal impairment

21. BNF Appendixes Appendixes 4 and 5  Prescribing in pregnancy and breast feeding Appendix 6 Intravenous additives  Table of common drugs given IV and how to prepare, dilute and administer them. prepare, dilute and administer them.

22. Yellow Card Reporting Doctors, nurses, pharmacists and patients may complete a yellow card report Report 1. All suspected reactions to new medicines (black triangle) 2. All serious suspected reactions to established medicines 3. Report all serious and minor reactions in children (<18yrs).

23. Sources of Prescribing Info  Trust Prescribing Policy  BNF/eBNF  IV guides/monographs  Trust Formulary  Specialist references (e.g. Paediatric)  Summary of Product Characteristics  Pharmacist  Medicines Information  Electronic access to central library of Trust approved guidelines.

24. Prescribing for children  Children are not little adults  Many drugs not licensed for use in children  Use a specialist children's formulary “BNF for Children”.  Weights and occasionally surface areas are required to calculate accurate doses. These parameters may change significantly in a relatively small time period. to calculate accurate doses. These parameters may change significantly in a relatively small time period.

25. Prescribing for Children  Pharmacokinetic changes in childhood are important and have a significant influence on drug handling.  The availability of a product does not ensure its suitability for use in children.

26. Prescribing for the Elderly  18% of the population are over 65yrs age.  Receive 1/3 of NHS prescriptions  Absorption, metabolism, distribution and elimination of drugs affected by ageing.  Renal function deteriorates with age.  Alzheimer’s disease, dementia and other cognitive disorders, Parkinson's disease are important disorders in the elderly.  Drugs such as NSAIDS, opioids, benzodiazepines etc are likely to cause problems in the elderly.

27. Prescribing for the Elderly Principles of prescribing  Avoid unnecessary drug therapy  Effect of treatment on quality of life  Treat the cause rather than the symptom  Drug history  Concomitant medical illness  Choice of drug  Dose titration  Dosage form  Packaging and labelling  Good record keeping  Regular review

28. Formularies & ‘Essential’ Drugs  National formularies (e.g. the BNF) provide an independent source of advice.  Hospital formularies reflect hospital choices, based on evidence based and cost-effective evaluation of the evidence base for a drug.  WHO provide a ‘model’ list of essential drugs (~300 items).

29. Common Prescribing Errors  Wrong drug (e.g. drugs that sound alike)  Wrong dose  Inappropriate Units  Poor/illegible prescriptions  Failure to take account of drug interactions  Omission  Wrong route/multiple routes (IV/SC?PO)  Calculation errors (important in Paediatrics)  Poor cross referencing  Infusions with not enough details of diluent, rate etc. Poor cross-referencing between charts  Once weekly drugs  Multiple dose changes