Pharmacogenetics is the study of how genetic factors influence individual responses to drugs. It analyzes individual differences in metabolic pathways that can affect how individuals respond therapeutically or experience adverse effects to medications. Pharmacogenomics takes a broader approach studying how all genes influence drug responses. Variations in genes involved in drug metabolism and targeting can impact drug efficacy and side effects. Examples include genetic polymorphisms affecting metabolism of antidepressants or blood thinners that require consideration of individual genetic differences for safe and effective treatment.

1. PHARMACOGENETICS

2.  Pharmacogenetics is a science that analysis
individuals responses to therapeutic agents &
the word pharmacogentics was first coined
by vogel of heidelberg
 Pharmacogenetics can thus be defined as the
science of determining the genetic difference
on metabolic pathways which can effect
individuals responses to drug both
therapeutically and adversely

3.  In general pharmacogenetics usually refers to
how variation in one single gene influences the
response to a single drug
 Pharmacogenomics is a broader term, which
studies how all of the genes (the genome) can
influence responses to drugs. However, these
terms are often used interchangeably.
 The risk for drug inefficacy or toxicity is a
product of the interaction of genes and the
environment. risk factors includes drug -drug
interaction,patients age, renal and liver function
or other disease factors or clinical variables such
as smoking alcohol consumption

4. Pharmacogenetics trait clinically relevant:
Three genetic mechanism can influence
pharmacotherapy first and best studies to
date are genetic polymorphisms of gene
which are associated with altered metabolism
of drugs.(e.g., metabolism of tricycle
antidrepressents)
 Increased or decreased metabolism of a drug
may change its conc. and of that of active,
inactive, or toxic metabolites.

5.  Second genetic variants may produce an
unexpected drug effect outside of its
therapeutic indication (e.g., hemolysis in
glucose-6-phosphate dehydrogenase
deficiency).
 Third, genetic variation in a drug target may
alter the clinical response and frequency of
side effect.(e.g., variants of the beta
adrenergic receptor alter response to beta
agonists in asthma patients).
 The quantiative role of a drug metabolizing
enzyme(e.g.,CYP2D6 )

6.  Phenotyping tests require the administration
of a specific marker drug or test drug, and
collection of urine, blood, saliva for analysis
of drug metabolite concentrations. these test
are time consuming, expensive and subject to
drug -drug interaction or other influences.
 Genotyping tests have the advantage og
having to be done only once in a lifetime and
providing unequivocal genetic information.
however, genotyping tests only identify a
group or category association (e.g., poor
metabolizer, ultrarapid metabolizer)

7. VARIATION INCIDENCE EFFECTS
Acetylation fast _ Need for higher or more frequent dose
of drugs that are acetylated (e.g.,
isoniazid) to produce the desired
therapeutic response
Acetlylation,
slow (drug
inactivation by
hepatic n-
acetyltransferase
About 50% of the us
population
Increased susceptibility to adverse
effects of drugs that are acetylated (e.g.,
with isoniazid, peripheral neuritis; with
hydralazine or procainamide, lupus)
G6PD deficiency 10% of black males
Higher prevalence in
people of
mediterranean
descent
With use of oxidant drugs, such as
certain antimalarials (e.g., chlorine,
primaquine),increased risk of hemolytic
anemia
HLA-B*1502 Mainly white
populations In some
asian countries,about
10 timer higher
Increased risk of adverse reaction to
carbamazepine, including serious
dermatologic reaction (e.g., stevens-
johnson syndrome)

8. CLINICALLYIMPORTANTGENETICPOLYMORPHISMOFDRUG
METABOLISMINFLUENCINGDRUGRESPONSE
GENE INCIDENCE OF
INDIVIUALS AT
RISK
DRUG DRUG EFFECT OR
ADR LINKEDTO
POLYMORPHISM
CYP2C9 14-28%
Heterozygote's
0.2-1%
homozygote's
Warfarin
Tolubutamide
Hemorrhage
hypoglycemia
cyp2c19 3-6% Caucasians
8-23% Asians
omeprazol Higher cure rates
when given together
with clarithromycin
Dihydropyri
mideine
dehydrogen
ase DPD
0.1% Diazepam
fluorouracil
Prolonged sedation
Neurotoxicity,myelo-
toxicity
Thiopurine
methyltrans
-ferase
TPMT
0.3% Mercaptopurine,
thioguanine,
azathioprine
myelotoxicity

9. REFERENCES:
 PHARMACOGENETICS BY URS A.MEYER
 PHARMACOGENETICSAND
PHARMACOGENOMICS BY JAGADEVAPPA
PATIL
 PHARMACOGENOMICS BY NATIONAL
INSTITUTE OF CENTRAL MEDICAL SCIENCE
 PHARMACOGENETICS IN GOOGLE

10. THANK YOU
BY
A.BHUVANESHWARAN
M.PHARM PHARMACEUTICS