Principles of Prescription Writing

1. Principles of Prescription Writing Dr SanjeewaniFonseka Department of Pharmacology

2. History • Prescriptions have been in use since ancient times • Latin adopted as standard language • “Rx” = prescription

3. Prescription drug • drug that requires a prescription because it is considered potentially harmful if not used under the supervision of a licensed health care practitioner

4. Definition A prescription is a written, verbal, or electronic order from a practitioner or designated agent to a pharmacist for a particular medication for a specific patient.

5. Writing PrescriptionsWho can write a Rx? • Practitioners • Physicians, veterinarians, dentists

6. Prescription Formatting Heading Body Closing

7. Current Prescription Formatting Heading Body Closing

8. Current Prescription Formatting • Heading • Name, address, and telephone number of the prescriber • Name, sex and age of the patient • Date of the prescription 3

9. Contents of the Prescription • Patient Name and Address • Full first and last name • Middle initial may be helpful • DOB – not required, but will be helpful in further identifying the correct patient to prevent medication errors

10. Contents of the Prescription • Practitioner’s Name, Address, and Phone number • Validates prescription • Provides contact information to clarify any questions

11. Contents of the Prescription • Date • Date the prescription is issued or written • Allows the determination of the life of the prescription to validate refills • Ensures continual patient supervision • Promotes patient follow - up

13. Current Prescription Formatting Heading Body Closing

14. Current Prescription Formatting • Body • The Rx symbol • Name • dose size or concentration (liquids) of the drug • Amount to be dispensed • Directions to the patient 4

15. Contents of the Prescription • Selecting the drug • Medication Allergies • Availability • Cost

16. Contents of the Prescription • Name of the drug • Multiple drugs per prescription can add to confusion • KEEP IT SIMPLE

17. Contents of the Prescription • Name of the drug - CAUTION: Look Alike/Sound Alike drug names • Massive number of new drug releases • Massive number of reformulations • Drug marketing strategy • Build on established names • New combination drugs – Use converged names

18. Contents of the Prescription • Name of the drug AVOID THE USE OF: • Abbreviations • Many drugs identified with abbreviations • EX: HCT for hydrochlorothiazide, MSO4 for morphine sulfate • Attempts to standardize abbreviations have been unsuccessful

19. List of dangerous abbreviations, acronyms, and symbols

20. Tablets - tab Capsule – cap Syrup – syr Suspension – susp Injection – Inj Metered dose inhaler – as such Lotion – as such

21. Contents of the Prescription • Strength of the drug • Be familiar with drugs and their various dosing strengths and dosage forms • When in doubt, use references

22. Dosing cont; • Weight – based dosing • Always convert patient weight to correct units (kg) • Liquid medications • One product may be available in a number of concentrations • Be familiar with various product concentrations • Indicate BOTH concentration and dose of medication • Example: Cephalexin suspension 125 mg/ 5 ml 1 teaspoon/ every 8 h

23. Contents of the Prescription • Strength of the drug • Decimal points • Avoid trailing zeros. EX. 5 mg vs. 5.0 mg; can be mistaken for 50 mg • Always use leading zeros. EX. 0.8 ml vs. .8 ml; can be mistaken for 8 ml

24. Contents of the Prescription • Quantity of the drug • Prescribe only necessary quantity • Write for specific quantities rather than time period (for example: dispense #30 vs. dispense for 1 month) • Calculate: quantity = frequency per day x treatment days • Writing out “Dispense # X” is helpful

25. Rules for writing quantity of drug: Quantities of 1 gram or more should be written in grams. Ex - write 2 g. Quantities less than 1 gram but more than 1 milligram should be written in Milligrams For eg, write 100 mg, not 0.1 g

26. Quantities less than 1 milligram should be written in micro / nano gram as appropriate. DO NOT abbreviate micro/ nanograms; since that can lead to Prescribing errors. For eg. write 100 micrograms, not 0.1 mg, nor 100 mcg, nor 100 μg Use ml or mL for milliliters

27. For some drugs, a maximum dose may need to be stated ( for eg. ergotamine in migraine & colchicine in gout). Eg: Ergotamine 1 mg at onset of attack & repeat every 30 min if necessary . Do not take more than 6 mg in one day or more than 12mg in one week

28. Contents of the Prescription • Directions for use • Write out in full English or use Latin abbreviations • Latin abbreviations – more convenient, more potential for mistakes • Avoid Dangerous Abbreviations • Provide clear and specific directions

29. Should be clearly indicated Atenolol100mg once daily Amoxicillin 250mgt.d.s. - Tell the patient what you mean be these times a day/ four times a day!

31. Contents of the Prescription • Determine preference for brand or generic product • Brand vs. generic • Is Brand always better? NO • If practitioner prefers brand, must indicate in print, - do not substitute

32. Sample Prescription-

33. Contents of the Prescription • Indication • Encouraged, seldom practiced • Helps confirm appropriateness of medication • Reminds patient of drug’s purpose • Facilitates communication between health care providers

34. Prescription Formatting Heading Body Closing

35. Current Prescription Formatting • Closing • Prescriber’s signature • Refill instructions • Generic substitution instructions 5

36. Contents of the Prescription • Refills • To avoid interrupting maintenance therapy, practitioners can authorize refills on a written prescription • Refills authorized are valid only for life of the prescription – 1 year

37. Controlled Substances Definition - a prescription drug whose use and distribution is tightly controlled because of its abuse potential or risk Regulation is more strict

38. Prescription for controlled drugs must(e.g.morphine) • Be completely written in the prescriber’s hand writing in ink • Be signed & dated • Carry the prescribers’ address • Carry the name & address of the patient • State the form of the drug • State the total quantity of the drug or the number of dose units to be disposed in both words & figures • State the exact size of each dose in both words & figure.

39. CASE #1 Poor handwriting contributed to a medication dispensing error that resulted in a patient with depression receiving the antianxiety agent Buspar 10 mg instead of Prozac 10 mg

40. CASE #2 A hypertensive patient accidentally received Vantin 200 mg instead of Vasotec 20 mg when a pharmacist misread this prescription

41. SUMMARY

42. MAXIMIZE PATIENT SAFETY ALWAYS write legibly. ALWAYS space out words and numbers to avoid confusion. ALWAYS complete medication orders. AVOID abbreviations. When in doubt, ask to verify.

43. Contents of the Prescription • Date of the order • Patient Name and Address • Name of the drug • Strength of the drug • Quantity of the drug • Directions for use • Practitioner Name, Address, Telephone number

44. Model Prescription • Name: ABC 2)Date: 31.07.07 • 3) Age:70yrs. 4) Sex: male • Diagnosis: Idiopathic Parkinsonism • Rx • 9) Tab Levodopa100mg • Tab Carbidopa25mg • 2 tablets by mouth 3 times daily for one month . • Take with food. • Dr. Sathya MD • Assistant Prof. Neurology, • Reg. No. 34523