Title 1. PHARMACOEPIDEMIOLOGY - DEFINITION AND SCOPE.pdf ✅

PHARMD GURU Page 2 NEED OF PHARMACOEPIDEMIOLOGY:  Lack of alternative models to investigate some drug events. Ex: To evaluate teratogenic effects of a new medicine.  Clinical trials are inadequate to detect less common ADR's.  Clinical trials conducted on highly selected patients without any co-morbidities and who taking no other medications.  Clinical trials don’t involve elderly, pediatric & pregnant patients.  Clinical trials investigate the single indication. Hence clinical trials fail to provide adequate information related to safety & efficacy of a drug under non-trial conditions & in other indications. In contrast, pharmacoepidemiology models provide alternative approaches to evaluate drug effects. AIMS OF PHARMACOEPIDEMIOLOGY: 1) Signal Generation. 2) Risk Quantification. 3) Hypothesis testing. 1) SIGNAL GENERATION: Signal generation is most commonly associated with ADR's, but also use to detect new applications of a drug. Ex: Minoxidil - First indicated for hypertension but case reports (signal generation) soon indicated that, it causes "HIRSUTISM" in a number of patients, side effect was investigated and now, it is marketed for purpose mainly stimulation of hair growth. 2) RISK QUANTIFICATION: Pharmacoepidemiology models can be applied for risk quantification, which make use of "Rule of three". Risk quantification of ADR's often requires large sample size. 3) HYPOTHESIS TESTING:  It requires the use of comparison groups to determine whether there are differences in variable of interest (Risk factors, drug exposed, Clinical conditions etc.)
PHARMD GURU Page 3  Statistical methods are used to assess whether the observed difference could have occur by chance alone. APPLICATION OF PHARMACOEPIDEMIOOLOGY: 1) ESTIMATION OF THE RISKS OF DRUG USE:  The risk involved in drug use can be estimated.  Risks & benefits of use of a drug may be weighed. Ex: Case reports of Triazolam induced CNS disturbances appear soon after its introduction to market. The drug was withdrawn in some countries. The reaction was likely due to "Dose related". Hence the problem was solved by recommending a lower dose. 2) USE IN PATIENT COUNSELING: Collection & analysis of observational data from other studies may help to address certain issues through counseling the patient. Ex: A pregnant patient may wish to terminate pregnancy, if there is a substantial risk for producing a seriously malformed child, but would also wish to proceed with the pregnancy, if the risk is low. 3) FORMULATION OF PUBLIC HEALTH POLICY DECISIONS:  Pharmacoepidemiology studies also help the policy makers to assess whether a drug should be withdrawn from the market or allowed to remain.  Qualitative & quantitative information of PEY studies helps to address many issues. Ex: If an inappropriate prescribing is observed among prescribers, regulatory agencies may impose restrictions on specific drugs (or) on practitioners. 4) FACILITATION OF PHARMACOECONOMIC EVALUATIONS: Data from PEY studies can be used to measure the effects of drugs on overall healthcare costs & resource consumption. Ex: Hospitalization due to serious adverse effects of a drug leads to more expenses as well as resource consumption, which could be avoidable.
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