Principles of
prescription
writing
Balakrishnan S
Lets introspect......
No.
No.
No.
No.
No.
with Department not written 71%
of drugs per prescription: 2.32
of drugs by generic: 26.8%
of drugs by brand name: 73.2%
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%
What is a prescription?
Drug prescription – A written or verbal order for a
medication by a licensed individual(physician,
dentist, veterinarian,etc)
History
• Prescriptions have
been in use since
ancient times
– Latin adopted as
standard language
– “Rx” = prescription
– “Sig.” = directions
Four common types of prescription:
1. Prescriptions in general practice
2. Hospital prescriptions for in-patients
3. Hospital prescriptions for a non hospital pharmacy
4. Private prescriptions
General Drug Information
Proprietary vs. nonproprietary

Single vs. compound

Dosage

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
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
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
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.
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.
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!
Route & method of administration:
should be clearly indicated.
Amount to be supplied
Any caution / warning
Model Prescription
1) 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
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)
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)
List of dangerous abbreviations, acronyms, and symbols
Abbreviation
Potential Problem
Preferred Term
U (unit)
Mistaken as zero, four, or cc
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”
Trailing zero and lack of
leading zero
Decimal point missed
Never write a zero by itself
after a decimal point, and
always use a zero before a
decimal point
MS, MSO4, MgSO4
Confused for one another
Write “morphine sulfate”
or “magnesium sulfate”
List of additional dangerous abbreviations, acronyms, and symbols
ABBREVIATON
POTENTIAL PROMBLEM
PREFERRED TERM
µg (microgram)
Mistaken for mg (milligram)
Write “microgram”
H.S. (at bedtime or half –
strength)
Mistaken for either meaning:
Also mistaken for every hour
Write out “half – strength” or
“at bedtime”
T.I.W (three times a week)
Mistaken for three times a day
or twice weekly
Write “three times weekly” or
“3 times weekly”
S.C. or S.Q. (subcutaneous)
Mistaken for SL for sublingual
or “5 every”
Write “Sub-Q” or “subQ” or
“subcutaneously”
D/C
Interpreted as discontine
whatever medication follows
(typically discharge meds)
Write “discharge”
c.c.
Mistaken for U (units) when
poorly written
Write “ml” for milliliters
A.S., A.D., A.U. (Latin
abbreviations for left, right,
both ears)
O.S., O.D., O.U. (Latin
abbreviations for left, right,
both eyes)
Mistaken for each other (A.S.
for O.S., A.D. for O.D., A.U. for
O.U., visa versa)
Write out “left ear” or “right
ear” or “both ears”
Write out “left eye” or “right
eye” or “both eyes”
??????
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.
DOCTOR’S ORDER SHEER
Patient’s Name:
No
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Drugs
Age / Sex:
PIMS No:
Strength Dosage freq Route Signature
DOCTOR INCHARGE:
1
2
3
4
5
6
7
8
9
10