Practical Pharmacology

Rational prescribing & prescription writing

Lab 19

Written prescription:

is the prescriber's order to prepare or dispense a specific treatment- usually medication- for a specific patient.

Drug:

Any substance or product that is used or intended to be used to modify or explore physiological systems or pathological states for the benefit of the recipient. They are used in 3 principle ways
1- curative as primary therapy. e.g. bacterial infection
2- suppressive of disease e.g. hypertension
3- preventive e.g. malaria

Names of drugs:

1- full chemical name
2- non proprietary name ( official or approved name) used in pharmacopoeias ( generic name e.g. barbiturates) .Advantages: clarity, economy& convenience
3- proprietary name or names that are commercial property of a pharmaceutical companies ( trade name) Advantages: quality esp. bioavailability

Elements of prescription

The elementary requirements of a prescription are that it should state what is to be given to whom and by whom. How much, how often ,by What route and sometimes for how long.
1-name of prescriber, address & office telephone number.
2- date on which the prescription written.
3- patient ś name, age, and address.
4- superscription- R ( Recipe) take thou.
5- inscription- the name and dose of the drug or drugs.
The traditional prescription comprises:
A- basis. The principle drug gives the prescription its chief action.
B- adjuvant. A drug that aids or increases the action of the principle ingredient.
C-corrective. Modifies or corrects undesirable effects of the basis or adjuvant.
D- vehicle. Agent used as the solvent in the solution, to increase the bulk, or to dilute the mixture.


6- subscription: directions to the pharmacist. Mix, make a solution, dispense. e.g. dispense 10 tab or 200 ml, make a solution, mix and make 10 caps.
7- transcription: instructions for the patient to be written on the container by the pharmacist. Label, mark. e.g. 1 tablespoonful 3 times daily, 1 cap twice daily.
8- signature.
9- refill, child proof container, warning.

Conversions between metric system & apothecary system.

1 grain (gr)= 0.065 g ≈ 60 mg
15 gr ≈ 1g
1 ounce (oz)= 30 ml
1 teaspoonful= 5ml
1 tablespoonful= 15 ml
1 minim= 1 drop
20 drops= 1ml
2.2 pounds (1b)= 1Kg.
20%= 20 g/ dl

Abbreviations:

ac before meals supp suppository
Aq water susp suspension
bid twice a day tab tablet
Cap capsule tid three times a day
g gram Tr tincture
gr grain prn when needed
h hour qs sufficient quantity
IA intraarterial stat at once
IM intramuscular µg microgram IV intravenous
OTC over the counter
Pc after meal
Po by mouth
PR per rectum
qid four times a day
Sc subcutaneous

Acute bronchitis

اسم الطبيب
العنوان
رقم الهاتف
اسم المريض التاريخ
العمر
العنوان
R
1- tetracycline 250 mg
dispense 20 cap
label : take one capsule four times daily.
2- paracetamol 500 mg
dispense 15 tab
label take one tablet three times daily
signatures

Fungal infection

R
benzoic acid 3.6g
salicylic acid 1.8 g
petrolatum to make 60 g
make an ointment
label apply a thin film to the affected part night & morning.


Painful myositis
Rx
Aspirin 0.3 g
Amobarbital 0.05g
make 20 such doses & place in 20 cap
label
كبسوله واحده 3 مرات يوميا

Renal colic

Rx
pot. citrate 2g
sod. bicarb 2g
conc. Infusion of buchu 2ml
syrup of orange 4ml
chloroform water up to 30 ml
Mix and prepare 480 ml
ملعقة طعام 3 مرات يوميا label