Pharmacovigilance Strategies for Detecting and Managing Adverse Drug Reactions
INTRODUCTION:
Pharmacovigilance is defined as ‘the science and activities relating to the detection, assessment, understanding and prevention of adverse events or any other drug- related problem. An Adverse event is ‘Harm caused by appropriate or inappropriate use of a drug whereas adverse drug reactions are a subset of these events, where harm (any noxious and intended effect) is directly caused by a drug under appropriate use. ADR are classified as
Type A – Augmented (Dose related)
Type B – Bizarre (Non – Dose related)
Type C – Chronic (Dose and Time Related)
Type D – Delayed (Time Related)
Type E – End of use (Withdrawal)
Type F – Failure (Unexpected failure of Therapy)
Pharmacovigilance plays a vital role in Detecting and Managing Adverse Drug Reactions.
METHODS OF DETECTION OF ADRS
Premarketing studies
Post marketing surveillance
Detected during hospital ward rounds
Screening of lab results
Premarketing Studies:
During the development of new medicines, their safety is tested in animal models.
Specific animal studies for carcinogenicity, teratogenicity and mutagenicity are also available.
Clinical trials are carried out in 3 different phases prior to the submission of a marketing authorization application.
Clinical trials normally identifies ADRs of frequency greater than .5-1.0%
However, there are limitations of detecting ADRs in clinical trials
Limitations of Detecting ADR in Clinical trials:
Limited patient number.
Restricted patient population.
Limited duration of patient exposure.
Patients with co- morbidities and intercurrent diseases excluded.
Rare and fatal reactions are often unnoticed during these studies.
Post Marketing surveillance:
Pharmacovigilance methodologies are used for detection of risk of risk and for the collection of risk information.
Powerful and cost-effective system for the identification of unknown drug- related risk is spontaneous adverse drug reactions reporting.
Health care practitioner should see it as a part of professional duty to report any suspicion of a drug unexpectedly causing an ADR for a patient under his care.
Als involves identifying product defect, intoxicants and abuse and unexpected lack of therapeutic effect.
First step in detection of ADR is collection of data.
Data collected includes,
Patients' demographic information
Presenting complaints
Past medication history
Drug therapy details including over the counter, current medications, medication on admission.
Lab data such as haematological, liver and renal function test.
Details of suspected ADR are collected
Time of onset
Duration of reaction
Nature and severity of reaction
Details of suspected drug (dose, frequency, time, duration, plasma concentration, previous reports on reported reaction.
Data on any other causes, including risk factors and predisposing factors.
To verify hypothesis of a causal link between drug exposure and an adverse outcome, epidemiological techniques are used.
Two epidemiological methods are most used they are:
Cohort studies
Control studies
Cohort studies: patient exposed to a particular drug are followed up actively and systematically and ADR frequencies are compared to an unexposed control population
Case control studies: Individuals affected by the adverse event being studied are identified. Each case is matched with disease- free control patients randomly recruited from the study base.
Both cases and controls are investigated for their exposure to possible causative agent prior to occurrence of the event.
The odd ratio calculated on the basis of exposure data.
The health care professionals should be very vigilant in detecting ADRs
ADR may be detected during ward rounds with medical team
ADRs detected during review of patient chart, patient counselling, medication history review, communicating with health professionals.
MANAGEMENT OF ADR’S:
Altering a dosage regimen or withdrawing a medicine suspected of causing an ADR are common methods of managing ADR in practice. However, the course taken to manage ADR is likely to vary from clinician to clinician. Under EU legislation, the approval of all new medicines onto the market must now be accompanied by a robust risk management plan from the marketing authorisation holder, which may involve the development of specific treatments for managing specific ADRs, as well as ongoing safety trials.
Examples of agent used in the management of specific adverse drug reactions:
CONCLUSION:
Pharmacovigilance plays a crucial role in detection, reporting and managing of Adverse drug reactions. Assess the safety and efficacy of drug. Pharmacovigilance methodologies are used for detection of risk and for the collection of risk information, reporting of ADRs and management of ADRs. It provides updated drug safety information to heath care professionals and other stakeholders.
REFERENCE:
Text book of pharmacovigilance: S K Gupta, Jaypee Brothers, Medical Publishers
Adverse Drug reactions: types and treatment options: MARC A. RIEDL, M.D., and ADRIANM.CASILLAS, volume 68, 2003.
Student name: Muppana Renuka
Student ID: 094/052023
Qualification: Pharm. D
E-Mail ID: muppanarenuka@gmail.com
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