Adverse Drug Reactions PDF
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Uploaded by yahiaakeely
AlMaarefa University
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Summary
This document presents an overview of adverse drug reactions, categorizing them by different characteristics and discussing the associated mechanisms. It tackles various types of drug responses, including hyporreactivity (tolerance and tachyphylaxis) and hyperreactivity, as well as the underlying biological processes.
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Adverse drug reactions Undesirable responses to drug therapy ADRs are common. About 2-6% of hospital admissions are for ADRs. Adverse reaction- – undesirable drug effect. Side effect- – This is similar to the term adverse reaction. – It is an unwanted but expected respo...
Adverse drug reactions Undesirable responses to drug therapy ADRs are common. About 2-6% of hospital admissions are for ADRs. Adverse reaction- – undesirable drug effect. Side effect- – This is similar to the term adverse reaction. – It is an unwanted but expected responses to a drug. Types of ADR’s A: – Augmented – dose related – Related to pharmacology (toxic effect or side effect--for example, digoxin toxicity) B: – Bizarre – non-dose related, – Unrelated to pharmacology (idiosyncratic for example, malignant hyperthermia, or immunological--for example, penicillin rash) C: – Continuous or chronic – Dose and time related, – Related to cumulative drug use--for or chronic example, NSAID induced renal failure D: – Delayed, – Delayed effect – Can be seen only some time after use of drug--for example Carcinogenic & teratogenic effects E: – End of use – Withdrawal – Related to discontinuation that is too abrupt--for example, addisonian crisis after steroid withdrawal Variation in drug response 1. Hypo-reactivity 2. Hyper-reactivity 1. Hyporeactivity to drugs Tolerance: – Decreased response to the same dose of the drug. – The same response could be obtained by higher doses. – It occurs over a long period Tachyphylaxis: – Rapidly occurring tolerance. Desensitization: – Decreased response to the agonist after its repeated injection in small doses. Probable mechanisms 1. Change in receptors 2. Loss of receptors 3. Exhaustion of mediators 4. Increased metabolic degradation 5. Physiological adaptation 2. Hyperreactivity to drugs Overshoot phenomena or intolerance Mechanism: – Up-regulation of the receptors: an increase in the number of receptors on the surface of target cells, making the cells more sensitive to a Examples: Propranolol Good luck
