Principles of prescription writing Balakrishnan S

1. Principles of prescription writing Balakrishnan S

2. Lets introspect...... No. with Department not written 71% No. of drugs per prescription: 2.32 No. of drugs by generic: 26.8% No. of drugs by brand name: 73.2% No. with name and designation not written 80.6% No. with doses not clear 47.6% No. with duration not written 53% No. Drugs not dispensed 5.8%

3. What is a prescription? Drug prescription – A written or verbal order for a medication by a licensed individual(physician, dentist, veterinarian,etc)

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

5. Four common types of prescription: • Prescriptions in general practice • Hospital prescriptions for in-patients • Hospital prescriptions for a non hospital pharmacy • Private prescriptions

6. General Drug Information • Proprietary vs. nonproprietary • Single vs. compound • Dosage

7. Parts of the prescription: 1) Superscription: Rx Also includes the patient details 2) Inscription: Ingredients, Quantity of each used 3)Subscription: Directions to the dispenser Directions to the patient Signature of the prescriber Date of writing the prescription

8. Following information must be given on a Prescription: 1)      Date 2)      Identification of the patient 3)      Formulation of the drug – eg Tablets - tab Capsule – cap Syrup – syr Suspension – susp Injection – Inj Metered dose inhaler – as such Lotion – as such

9. Rules for writing quantity of drug: a)Quantities of 1 gram or more should be written in grams. For example, write 2 g. b) Quantities less than 1 gram but more than 1 milligram should be written in Milligrams For eg, write 100 mg, not 0.1 g c) 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 d) If a decimal point cannot be avoided for values under 1, write a zero before it, for example write 0.5ml not .5ml

10. Rules for writing quantity of drug: e) Use ml or mL for milliliters f) For liquid oral medicines: The dose should be stated as the number of milligrams in either 5 ml or 10ml, Since these are readily measured amounts, & special spoons are provided to patients for the measurements.

11. Rules for writing quantity of drug: 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.

12. Frequency of administration : Should be clearly indicated Atenolol 100mg once daily Amoxicillin 250mg t.d.s. (Accepted abbreviations may be used! BUT DO NOT USE) - Tell the patient what you mean be these times a day/ four times a day!

13. Route & method of administration: - should be clearly indicated. Amount to be supplied Any caution / warning

14. Model Prescription • Name: ABC 2)Date: 31.07.07 • 3) Age: 70yrs. 4) Sex: male • 5) Address: 20, III Cross, Eswaran koil st. • Pondicherry 605 002 • 6) PIMS No: 0298298 • 7) Diagnosis: Idiopathic Parkinsonism

15. Model Prescription 8) Rx 9) Tab Levodopa 100mg Tab Carbidopa 25mg 10) Dispense 100 combination tablets 11) Take 2 tablets by mouth3 times daily with breakfast, lunch and dinner. Take with food. 12) Dr. Sathya MD 13) Assistant Prof. Neurology, 14) PIMS, Pondicherry 605 014 15) Ph: 0413-2207654 16) Reg. No. 34523 17) (TN medical council)

17. Look Alike/Sound Alike Names • CASE # 1: • Serzone (nefazodone) vs. Seroquel (quetiapine) • (antidepressant) (antipsychotic) • Similar overlapping strengths (100 mg and 200 mg) • Similar dosage forms (tablets) • Similar dosing interval (BID) • Similar titration schedule • Often stocked in close proximity on pharmacy shelf • Prescribing and dispensing errors have led to a number of • adverse events (N/V, hallucinations, AMS, lethargy, • seizures, death)

18. List of dangerous abbreviations, acronyms, and symbols

19. List of additional dangerous abbreviations, acronyms, and symbols

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21. 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.