This document discusses posology, which is the science of determining drug doses. It begins by defining posology and its importance. Several factors that influence drug dosing are then outlined, including age, weight, disease presence, and route of administration. Various methods for calculating drug doses for children and animals are presented, such as Young's formula and calculations based on body surface area. Considerations for veterinary and homeopathic dosing are also covered. The document concludes with defining posology as the study of determining appropriate drug doses based on patient characteristics.

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