The presentation aims to give a basic understanding about the various drug reactions. It explains the mechanisms of ADR, Types, predisposing factors for ADR, and other common drug related adverse events

1. Jobin Kunjumon Vilapurathu
Asst. Professor
Grace College of Pharmacy, Palakkad

2.  Mechanisms of ADR
 Numerous pharmacological actions of same drug
 Immunological and hypersensitive reactions to a
drug
 Drug Interactions

3.  The American Society of Health System
Pharmacists (ASHP) defines ADRs as any
unexpected, unintended, undesired or
excessive response to a drug that includes
 Requires discontinuing the drug
 Requires changing drug therapy
 Requires modifying dose
 Necessitates or prolong stay in Hospital
 Complicates Diagnosis
 Negatively affects prognosis or result in temporary
or permanent harm, disability or death

4.  Type A (Predictable/ Augmented)
 Predictable on the basis of known pharmacologic action of the
drug
 Exaggerated but normal pharmacological actions and are dose
related
 Type B (Qualitative)
 Bizarre or unpredictable effects, unexpected from known
pharmacological actions of drug
 Not dose related
 Usually hyper sensitive or immune-based further sub divided
to
 Type I ( IgE mediated)
 Type II ( IgG or IgM mediated cytotoxic reaction)
 Type III ( IgG mediated immune complex reaction)
 Type IV ( Cell mediated immune reaction)

5.  Type C
 Both dose related and time related
 Occurring due to the long term use of the drug
 Type D
 Only time related
 They are the delayed drug effects, such as due to
carcinogenicity or teratogenicity
 Factors predisposing to ADRS
 Drug Related Factors
 Patient Related Factors

6.  Drug Related Factors
 Dose
 Dosage form and delivery system
 Interactions between drugs
 Patient Related Factors
 Age - Geriatrics
 Age – Pediatrics
 Concurrent diseases
 Hepatic disease
 Renal disease
 Other diseases
 Genetic factors
 Gender
 Nutrition

7.  On basis of severity, classified as
 Minor : no therapy, antidote or prolongation of
hospitalization required
 Moderate : require change in drug therapy, specific
treatment, prolongs hospital stay
 Severe : life threatening, intensive treatment
 Lethal : death of patient
 Prevention of ADR
 Avoid all inappropriate use of drugs
 Use appropriate dose, route & frequency
 Consider previous history of DR
 Rule out possibilities of DI
 Carry appropriate laboratory monitoring