Principles of Prescription Writing
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Transcript Principles of Prescription Writing
Principles of Prescription Writing
Dr Sanjeewani Fonseka
Department of Pharmacology
History
Prescriptions have
been in use since
ancient times
Latin adopted as
standard
language
“Rx” =
prescription
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
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.
Writing Prescriptions
Who can write a Rx?
Practitioners
Physicians, veterinarians, dentists
Prescription Formatting
Heading
Body
Closing
Current Prescription
Formatting
Heading
Body
Closing
Current Prescription
Formatting
Heading
Name, address, and telephone
number of the prescriber
Name, sex and age of the
patient
Date of the prescription
3
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
Contents of the Prescription
Practitioner’s Name, Address, and Phone
number
Validates
Provides
prescription
contact information to clarify
any questions
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
Current Prescription
Formatting
Heading
Body
Closing
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
Contents of the Prescription
Selecting
the drug
Medication
Availability
Cost
Allergies
Contents of the Prescription
Name of the drug
Multiple drugs per prescription can add to
confusion
KEEP IT SIMPLE
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
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
List of dangerous abbreviations, acronyms, and symbols
Abbreviation
Potential Problem
Preferred Term
U (unit)
Mistaken as zero, four
Write “unit”
IU (international unit)
Mistaken as IV or 10
Write “international unit”
Q.D., Q.O.D.
Mistaken for each other.
Period after Q and O after Q
can be mistaken for “I”
Write “daily” and “every
other day”
MS, MSO4, MgSO4
Confused for one another
Write “morphine sulfate” or
“magnesium sulfate”
Tablets
- tab
Capsule
– cap
Syrup
Suspension – susp
Injection
Metered dose inhaler – as such
Lotion – as such
– syr
– Inj
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
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
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
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
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
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
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
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
Should be clearly indicated
Atenolol 100mg once daily
Amoxicillin 250mg t.d.s.
- Tell the patient what you mean be these
times a day/ four times a day!
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
Sample Prescription-
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
Prescription Formatting
Heading
Body
Closing
Current Prescription
Formatting
Closing
Prescriber’s
signature
Refill instructions
Generic substitution
instructions
5
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
Controlled Substances
Definition
- a prescription drug
whose use and distribution is
tightly controlled because of its
abuse potential or risk
Regulation is more strict
Prescription for controlled drugs must(e.g.morphine)
1. Be completely written in the prescriber’s hand
writing in ink
2. Be signed & dated
3. Carry the prescribers’ address
4. Carry the name & address of the patient
5. State the form of the drug
6. State the total quantity of the drug or the number
of dose units to be disposed in both words &
figures
7. State the exact size of each dose in both words &
figure.
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
CASE #2
A hypertensive patient accidentally received Vantin 200 mg
instead of Vasotec 20 mg when a pharmacist misread this
prescription
SUMMARY
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.
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
Model Prescription
1) Name: ABC
3) Age: 70yrs.
2) Date: 31.07.07
4) Sex: male
Diagnosis: Idiopathic Parkinsonism
Rx
9) Tab Levodopa 100mg
Tab Carbidopa 25mg
2 tablets by mouth 3 times daily for one month .
Take with food.
Dr. Sathya MD
Assistant Prof. Neurology,
Reg. No. 34523