Posology and it's significance

1. TOPIC
PRESENTED BY:
STREAM:
YEAR:
SEMESTER:
MENTOR SEMINAR~ (4)

2. TOPICS SLIDE NO.
1. INTRODUCTIONTO POSOLOGY 3
2. FACTORSINFLUENCINGDOSE 4
3. CALULATIONS OF DOSES 5-8
4.VETERINARY DOSES 9
5. HOMEOPATHIC POSOLOGY 10
6. CONCLUSION 11
7. REFERENCES 12

3. POSOLOGY~
INTRODUCTION
 Posology derivedfromthe two greekwords:–
• “posos” = how much
• “logos” = science
 It isa branchof medicalscience whichdealswithdose or quantityof drugs
whichcan be administeredto a patient to getthe desiredpharmacological
actions.
 It isthe responsibility of the prescriberregardingthe amountof the drugto
be prescribedor thefrequency atwhich the drugto be administered.
 But before dispensinganyprescription,it becomes the duty of the
pharmacistto satisfy himself that the overdosehasnot been prescribed.
Thiscan be confirmedeither fromthe prescriberor by consulting the
pharmacopeia.

4. FACTORS
INFLUENCING
DOSE
 The optimum dose of a drug whichproduces the desired therapeuticeffect may varies
from person to person.
 There are various factors which influencethe dose of a drug, some are as follows~
Age
Gender
Body weight
Idiosyncrasy
Tolerance
Tachyphylaxis

5. FACTORS
INFLUENCING
DOSE
Enviromental
factors
Route of
Administration
Presence of
disease
Accumulation
Additive effects
Metabolic
disturbance

6.  The dose of a drug given in the pharmacopoeia represents the average maximum
quantity of drugs whichcan be administered to an adult orally within 24 hours.
 There are number of methods by which the dose for a childcan be calculatedfrom the
adultdose .
1] Young’s Formula
2] Dilling’sFormula
3] Fried’s Formula
4] Clarke’s Formula
CALCULATIONS
OF DOSES
 Whenever other route is used then the dose is adjustedaccordingly.
 Actually, the doses are calculatein proportion to age, body weight and surface area of
patient.
5] Calculationsbased on body surfacearea

7.  Diling’sformula:
Example:
The dose of a childof 10 years if the adultdose is 600mg
Therefore, the dose of the child is=>
10/20 ×100 =300 mg
.
 Young’s formula:
Example:
The dose for a childof 5 years if the adult dose is 400mg
Therefore, the dose of the child=>
5/ (5+12) ×100 =117 mg (APROXX)
*This formula is used for calculatingthe doses of childrenof 12 years.
DOSE FOR A CHILD=AGE ( inyears) × ADULTDOSE
20
DOSE FOR A CHILD=AGE (inyears) × ADULTDOSE
AGE + 12
*Thisformula is used for calculatingthe doses of childrenbetween 4 to 20 years of
age
• DOSESPROPORTIONATETO AGE-there is a number of methods by which the dose for a childcan be calculatedfrom the adultdose.

8.  Freid’sformula:
Example:
The dose for a 8 month old infantif the average adultdose of a drug is 400mg
Therefore, the dose of the child=> 8/150 ×100 = 13.3 mg
*This formula is used for calculatingthe doses of infants.
 Calculationsbased on body weight-
Clarke’sformula:
*This formula is applicableonly when child dose is lessthan 150 lb or 70 kg.
DOSE FOR A CHILD=AGE ( inmonths) × ADULTDOSE
150
• DOSE = WEIGHTIN lb × ADULTDOSE(mg)
150
• DOSE = WEIGHTIN kg × ADULTDOSE (mg)
70

9.  Calculationsbased on body surfacearea-
• The calculationof childdose according to surface area is more satisfactory and
appropriate rather than the method based on age.
• The method is more complicatedthan the method based on age.
• The method is basedon the following formula-
PERCENTAGEOF ADULT DOSE= SURFACEAREAOF CHILD ×100
SURFACEAREAOF ADULT

10. VETERINARY
DOSES
 Veterinary doses. The dose required for animalsare more or on higherin
comparison of human beingsjust becauseof body weight,size etc. Therefore it’s
very important for supply the correct dose
 FactorsAffectingOn VeterinaryDoses:

11.  A homoeopathic concept of Posology necessarilymeans selectionof potency, dispensing
and repetitionof the dose of the medicine.Homoeopathic Posology is based on the
principlesof the single remedy, minimum dose and minimum intervention.
 The selectionof the dose is as much an integralpart of the process of making a
homœopathic prescription as the selectionof the remedy, and often quiteas important.
 A well selectedremedy may fail utterly, or even do injury, because of wrong dosage.
Dose as well as remedy must be adjustedto the patient’sneed.
 Since after the death of our master Dr.Hahnemann, Posology remains a topic for
controversy and confusion for beginners.
 After perceivingthe concept of HahnemannianPosology various stalwarts likeDr.
Boenninghausen, Dr.Kent, and Dr.Boger etc have tried to express their own perception in
a differentmanner.

12. CONCLUSION
• Basicallythe word Posology has originatedfrom the Greek word Posos. The meaning of
this word is how much [dose]. The word logos suggeststudy or discourse. So Posology
means scienceof dosage.
• The terminology of dose originatesfrom the word dose that means the quantityof a
drug or other therapeuticagent to be taken or applied.
• On the basisof this we may say that Posology is the branch of pharmacology and
therapeuticsconcerned with a determinationof the doses of remedies; the scienceof
dosage.
• Or Posology isthe scientificstudy of drug doses.
• The dose of a drug cannot be fixed rigidlybecause various factors are responsible i.e
age, sex, severity of the diseaseetc.

13. REFERENCES
 R. M. Mehta, pharmaceutics-II,second adition-2003,reprint2010,vallabh prakashan.
Pg. No. 65 to 72
 The Free Dictionary[Internet]."posology". The Columbia ElectronicEncyclopedia®,
Columbia UniversityPress, 2013 [cited7 Jul. 2022]. Available
from: https://encyclopedia2.thefreedictionary.com/posology
 JACKSON, J. HAMILTON."POSOLOGY." UnitedStatesMedicalInvestigator(1875-
1887) 5, no. 10 (1877): 498.
 Manzanares, William,and GilHardy. "Seleniumsupplementationin the criticallyill:
posology and pharmacokinetics." Current OpinioninClinicalNutrition& Metabolic
Care 12, no. 3 (2009): 273-280.

14. THANKYOU