Transcript Principles of Prescription Writing

Principles of Prescription Writing
Dr Sasan Zaeri
(PharmD, PhD)
Department of Pharmacology
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
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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
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Types of Prescriptions

Generic Name The nonproprietary name
(based on pharmacological group)


e.g., Amoxicillin, Fluoxetine, Diazepam, Aspirin
Brand Name The proprietary name provided
by pharmaceutical company who holds the
patent on the drug

e.g., Prozac®, Viagra®, Xanax®
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Types of Prescriptions (cont’d)

Compounded Requires the preparation of one
or more active ingredients with one or more
pharmaceutical necessities, e.g., suspending
agent, flavoring agent, to create a finished
product.
For example, an oral compounded prescriptions may be
used to facilitate the administration of a solid dosage
form that is not available in liquid form for patients
unable to swallow a solid dosage form.
 e.g., pediatric, geriatric
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Types of Prescriptions (cont’d

New An original prescription order dispensed
for the first time

Refill A repeat dispensing of the original
prescription order
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Prescription Formatting
 Heading
 Body
 Closing
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Sample Prescription-
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Prescription Formatting

Heading
 Name, address, and telephone number of the
prescriber



Name, sex and age of the patient


Validates prescription
Provides contact information to clarify any questions
Age is important if for a pediatric or geriatric patient
Date of the prescription
 to validate refills, to ensure pt supervision
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Prescription Formatting

Body
1. The Rx symbol
2. Drug dosage form
3. Drug name
4. Dose size or concentration
5. Quantity to be dispensed (#)
6. Directions to the patient
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Contents of the Prescription
 Selecting
the drug

Medication Allergies

Availability

Cost
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Contents of the Prescription

Abbreviations of dosage forms

Tablets
- Tab

Capsule
– Tap

Syrup – Syr

Suspension – Susp

Injection

Lotion – as such

Spray- as such
– Inj
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Contents of the Prescription

Name of the drug- CAUTION:

Be very cautious about drug names
that “sound/look” alike

e.g. Flagyl vs. Plasil
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Contents of the Prescription

Name of the drug- AVOID the use of Abbreviations

DO NOT use abbreviations for drugs prescribed
unless the abbreviation is official and routine:

SSKI (Saturated Solution of Potassium Iodide)

NS (Normal Saline)

NTG (Nitroglycerin)

MTX (Methotrexate)

MOM (Milk of Magnesia)
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Contents of the Prescription

Strength of the drug
 Be
familiar with drugs various
dosing strengths and dosage forms
 When in doubt, use references

Writing no strength means prescribing the
lowest available strength
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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
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Contents of the Prescription




Quantity of the drug (#)
Avoid writing a prescription for a large quantity of
drug unless it is absolutely determined that such a
quantity is necessary
For chronic medication, it is better to start with a lower
number at first in the event that the patient cannot
tolerate it because of side effects
Economic considerations (Limitation by insurance
organizations)
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Contents of the Prescription

Quantity of the drug

Quantity (#) = frequency per day x treatment
days
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Contents of the Prescription

Directions for use

Avoid “as directed” as far as possible

Write out in full English or use Latin
abbreviations
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Contents of the Prescription

Latin abbreviations – more convenient,
more potential for mistakes

Avoid Dangerous Abbreviations
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List of dangerous abbreviations, acronyms, and symbols
Abbreviation
Potential Problem
Preferred Term
U (unit)
Mistaken as zero, four, cc
Write “unit”
ug
Mistaken as mg
Write “microgram”
IU (international unit)
Mistaken as IV or 10
Write “international unit”
Q.D
Mistaken for QID
Period after Q can be
mistaken for “I”
Write “daily”
MS, MSO4, MgSO4
Confused for one another
Write “morphine sulfate”
or “magnesium sulfate”
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Rules for writing amount 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

e.g, write 100 mg, not 0.1 g
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

Quantities less than 1 milligram should be
written in microgram
DO NOT abbreviate micrograms

eg. write 100 micrograms, not 0.1 mg, nor 100
mcg, nor 100 μg
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Prescription Formatting
 Heading
 Body
 Closing
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Prescription Formatting
 Closing
 Generic
substitution
instructions
 Refill instructions
 Prescriber’s signature
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
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 or brand
necessary
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Sample Prescription-
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Contents of the Prescription

Refills
 To avoid interrupting maintenance therapy

Refills “N” times or NR. Leaving this section blank
implies that the prescription is non- refillable

a prescription refill for a conventional, non-controlled
medication has a one year expiration time
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MAXIMIZE PATIENT SAFETY

ALWAYS write legibly

Use the same pen for the entire prescription

If a mistake is made, e.g., number of tablets,
cross out the mistake, write “error” above it,
and then initial it


AVOID abbreviations
When in doubt, ask to verify
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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
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CASE #2
A hypertensive patient accidentally received Vantin
(cefpodoxime) 200 mg instead of Vasotec (enalapril) 20 mg
when a pharmacist misread this prescription
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Can you read this?
Tegretol (carbamazepine) or
TEQUIN (gatifloxacin) ???
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