JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD Pharm. D V Year PHARMACOEPIDEMIOLOGY AND PHARMACOECONOMICS Previous Question Paper (June/July - 2022 - R08)

Pharmacoepidemiology originated in the 1970s and 1980s as a response to the need for systematic post-marketing surveillance of drugs. It emerged from the intersection of clinical pharmacology and epidemiology, driven by high-profile drug safety concerns such as the thalidomide tragedy and the need to understand drug effects in large, diverse populations rather than just controlled clinical trials.

The evaluation of pharmacoepidemiology involves assessing the safety, efficacy, and patterns of drug use in real-world settings. It utilizes observational study designs, such as cohort studies, case-control studies, and case-series, to quantify the risk-benefit profile of medications. Key evaluation metrics include incidence rates of adverse drug reactions, drug utilization patterns, and long-term therapeutic outcomes.

The need for pharmacoepidemiology arises because clinical trials are often limited by small sample sizes, short durations, and strict inclusion criteria that exclude vulnerable populations like the elderly, pregnant women, and patients with comorbidities. Pharmacoepidemiology is essential for detecting rare adverse events, identifying drug-drug interactions, monitoring off-label use, and providing the evidence base for regulatory decisions and clinical guidelines.

The Defined Daily Dose (DDD) is a statistical unit of measurement used to standardize the comparison of drug consumption across different populations and time periods. It represents the assumed average maintenance dose per day for a drug used for its main indication in adults.

The principles of DDD assignment include:

• The DDD is assigned based on the recommended daily dose for the main indication in adults. If multiple indications exist, the one with the highest volume of use is prioritized.
• It is a technical unit of measurement and does not necessarily reflect the prescribed or recommended daily dose for an individual patient, as clinical practice varies based on age, weight, and severity of disease.
• The DDD is assigned in terms of the active ingredient, typically expressed in grams, milligrams, or international units.
• DDD values are maintained and updated by the WHO Collaborating Centre for Drug Statistics Methodology to ensure international consistency.
• It is not intended for use in pediatric populations, as doses for children are often weight-based and do not align with adult-standardized DDDs.
• DDD assignment assumes that the drug is used for its primary therapeutic purpose; therefore, it is not suitable for drugs with multiple indications where doses vary significantly between them.