What are the factors that affect drug action?
                     WHAT ARE THE FACTORS THAT 
AFFECT DRUG ACTION?
VARIATIONS IN DRUG 
RESPONSE
DIFFERENCE IN PHARMACOKINETIC 
HANDLING
OF DRUGS – VARIABILITY IN PLASMA 
CONC.
RECEPTOR NO. OR STATE 
DIFFERENCE
OTHER HOST AND ENVIRONMENTAL 
FACTORS
Source: gmch.gov.in
FACTORS AFFECTING 
DRUG ACTION
BODY SIZE
PREGNANCY
LACTATION
AGE – PEADIATRIC & GERIATRIC
GENETIC FACTORS
DISEASE STATES – KIDNEY & LIVER
ROUTES OF DRUG ADMINISTRATION
Source: gmch.gov.in
BODY SIZE
INFLUENCES THE CONCENTRATION OF 
DRUG ATTAINED AT THE SITE OF ACTION
AVERAGE ADULT DOSE FOR – MEDIUM 
BUILT
FOR EXT.OBESE OR LEAN INDIVIDUAL –
INDIVIDUAL DOSE = BW(kg)/70 Χ 
AVERAGE
ADULT DOSE
Source: gmch.gov.in
DRUG THERAPY IN 
PREGNANCY
MOST DRUGS CAN CROSS THE PLACENTA 
AND EXPOSE THE DEVELOPING EMBRYO 
AND FETUS TO THEIR PHARMACOLOGIC 
AND TERATOGENIC EFFECTS .
AS A RULE TRY TO AVOID GIVING ANY DRUG 
DURING PREGNANCY, IF POSSIBLE
Source: gmch.gov.in
FACTORS AFFECTING 
PLACENTAL DRUG
TRANSFER 
 THE PHYSICOCHEMICAL PROPERTIES OF 
DRUG.
RATE AT WHICH DRUG CROSSES THE 
PLACENTA AND AMOUNT OF DRUG 
REACHING THE FETUS.
DURATION OF EXPOSURE TO DRUG
Source: gmch.gov.in
FACTORS AFFECTING 
PLACENTAL DRUG
TRANSFER CONT.
DISTRIBUTION CHARACTERISTICS IN 
DIFFERENT
FETAL TISSUES.
STAGE OF PLACENTAL AND FETAL 
DEVELOPMENT AT THE TIME OF EXPOSURE TO 
DRUG.
THE EFFECTS OF DRUGS USED IN 
COMBINATION.
Source: gmch.gov.in
LIPID SOLUBILITY
DRUG PASSAGE ACROSS THE PLACENTA IS
DEPENDENT ON
LIPID SOLUBILITY AND
 DEGREE OF DRUG IONIZATION
Source: gmch.gov.in
TOXIC DRUG REACTIONS 
IN FOETUS
ANGIOTENSIN CONVERTING ENZYME 
INHIBITORS DURING PREGNANCY CAN 
RESULT IN SIGNIFICANT AND IRREVERSIBLE 
RENAL DAMAGE IN FOETUS.
Source: gmch.gov.in
TERATOGENIC DRUG 
ACTIONS
 SINGLE INTRA‐UTERINE EXPOSURE TO A 
DRUG CAN AFFECT THE FETAL STRUCTURES 
UNDER‐GOING RAPID DEVELOPMENT AT 
THE TIME OF EXPOSURE .
Source: gmch.gov.in
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