1. Prescription Writing
Lab Lecture

2. Prescription
The prescriber’s written order to prepare or dispense a specific treatment (usually a medication) for a specific patient
Who can write a prescription?
Physician
Dentist
Veterinarian
Nurses are authorized to administer medications
Pharmacists are authorized to prepare and dispense drugs

3. Definition of terms
Generic name or International Non-proprietory Name (INN) – the scientifically and internationally recognized name for their active ingredient/s
Drug product – finished product containing the active ingredient, may also contain inactive ingredients
Fixed Dose Combination (FDC) – containing 2 or more active ingredients

4. Rational Prescription Writing
Make a specific diagnosis
Consider the pathophysiologic implications of the diagnosis
Select a specific therapeutic objective or goal.
Select a drug of choice
Determine the appropriate dosing regimen
Devise a plan for monitoring the drug’s action and side efects and determine end point for therapy
Plan a program of patient education.
3. objective. Ex. pain relief. Bacterial eradication.
Ex. fever due to UTI. Decrease pain and fever only? Vs treating the infection. May be more than 1 objective or goal.

5. Rational Prescription Writing
Rule of Right
Right drug, for the right patient, with the right diagnosis, at the right dose, right route, right intervals, right duration of therapy under prevailing constraints
SANE Criteria:
Safety
Affordability
Need
Efficacy
Choose drugs that are clearly needed and scientifically proven to be effective
Do not be influenced by patient pressure or med rep pressure

6. Elements of a prescription
Identity of the prescriber
Full name, address and contact number on top
License number, PTR, S2 number
Signature
Identity of the patient
Full name, age, address, sex (weight – optional)
Date
Body of the prescription
Superscription
Inscription
Subscription and Refill information
Transcription

7. Elements of a prescription
3. Body of the prescription
Superscription = Rx = “take thou”
Inscription
Name of medication (generic and brand)
Strength and and dosage to be dispensed
Subscription and refill information
Instruction to pharmacist for quantity of medication
Refill or not
Transcription = sig. = “label”
Directions for use: route, interval, duration, purpose
Other instructions

9. Why Generic?
Every generic drug product should be as satisfactory as the trade-named product
Generic drugs have the same bioavailability
Bioequivalent to a reference standard formulation
These drugs must have the same rate and extent of absorption
Should not differ between manufacturers
Generic names allow substitution of medicines by the pharmacist
Due to unavailability, cost, etc.

10. Why Generic? Generic names Of distinct sound and spelling
Grouped or related drugs may have similar prefixes of suffixes to easily identify their class
-ac = anti-inflammatory agents/NSAIDS
Cef- = cephalosporins
-cillin = penicillin group
-dipine = calcium channel blockers
-olol = beta blockers
-tidine = H2 antagonists (antacids)
-pril = ACE inhibitors

11. Prescribing errors Must be legible, unambiguous, dated and signed
Should contain sufficient information to permit the pharmacist or nurse to discover possible errors before the drug is dispensed or administered

12. Prescribing errors Omission of information Poor prescription writing
Continue pre-operative medicines
Continue eye drops
Poor prescription writing
Poor handwriting
Misplaced decimal point
Abbreviations that may be misread
Ex. 10U or 10μg may be read as 100
Does the abbreviation OD mean once a day or right eye?
Continue all meds? Do we discontinue one? For how long? Etc.
To which eye? Both? Just one?

13. Prescribing errors Inappropriate drug prescriptions
Failure to recognize contraindications imposed by other diseases the patient may have
Failure to obtain information about other drugs the patient is taking (ex. drug-drug interactions)
Failure to recognize possible psychochemical incompatibilities between drugs (ex. disulfiram and alcohol)

14. Compliance
The extent to which patients follow treatment instructions (adherence)
Fail to buy/obtain the medication
Fail to take the medication as prescribed
Prematurely discontinues the medication
Patient or another person takes medication inappropriately (ex. sharing of meds)

15. Off labeled use of drugs
Not the actual intention of the drug, but may seem to be beneficial in some cases
Ex. Finasteride = initially a medicine for BPH, now a medicine for hair loss

16. Pediatric Dosing Suspensions or syrups or drops
Calculated based on weight
Dose recommendations based on weight
Ex. paracetamol: 10-15mg/kg/dose, given every 4 hours
Ex. amoxicillin: 30-40mg/kg/day divided into 3 doses
Dose recommendations based on age and average weight
Decongestants: phenylpropanolamine or phenylephrine
2-6 years = 2.5mL QID
7-12 years = 5mL QID
Cetirizne
6months-2 years: 2.5mg/day
2 years -5 years: 5mg/day or 2.5mg BID

17. Case 1
S> An 18 year old student came to the clinic due to nasal congestion, slightly productive cough x 2 days. No fever. No vomiting. No pain. Able to eat well. Slight discomfort during sleeping
O> Pertinent PE: Temp: 36.8C, not in distress. boggy turbinates, slightly hyperemic pharynx, clear breath sounds.
A>
P>

18. Case 1 Available drugs Decolgen Sinutab Neozep Bioflu Solmux
Mucosolvan
Ventolin nebulizer
Benadryl expectorant

19. Case 2
S> 6 year old male, came to you for fever and sore throat for 3 days duration. Decreased appetite, no vomiting or diarrhea. No cough or colds. No other complaints. Mother says her son has G6PD deficiency
O> Weight = 20kg, Temp = 38.5C, not in distress. Normal nose and ears. Hyperemic tonsils with exudates. Clear breath sounds and heart sounds.
A>
P>

20. Case 2 Available antibiotics Amoxicillin Co-amoxiclav Chloramphenicol
Co-trimoxazole
Metronidazole