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Drug idiosyncrasy
- 1. DRUG IDIOSYNCRASY Dr.Nafeeya Department of ForensicMedicine & Toxicology
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- 3. Categories Side effects Secondary effects Toxic effects Intolerance Idiosyncrasy Drug allergy Photosensitivity Drug dependence Drug withdrawal reactions Teratogenicity Mutagenicity and Carcinogenicity Drug induced diseases (Iatrogenic disorders) Iatrogenic, Idiosyncrasy, Idiopathic, Intolerance
- 6. Classification of AdverseDrug Reactions ● Depending upon- ● Type of reaction: • Type A • Type B • Type C • Type D • Type E • Type F Onset of event: Acute (<60 minutes) Sub-acute (1-24 hrs) Latent (>2 days) Severity: Minor, Moderate, Severe, Lethal ADRs.
- 7. Types of AdverseDrug Reactions • Augmented(dose related) • Bizarre (Non-Dose Related) • Chronic (Dose Related and Time Related) • Delayed (Time Related) • End of Use (Withdrawal) • Failure (Unexpected Failure of Therapy)
- 8. Bizzare (Non-Dose Related) ●Features • Uncommon • Not related to the pharmacologic action of the drug • Unpredictable • High mortality ● Example • Immunologic reactions: anaphylaxis to penicillin • Idiosyncratic reactions: malignant hyperthermia with general anesthetics Management •Withhold and avoid in future I d o s y n c r a z y
- 9. Classification of ADRs-Dependingon Severity •Minor ADRs: No therapy, antidote or prolongation of hospitalization is required. • Moderate ADRs: Requires change in drug therapy, specific treatment or prolongs hospital stay by atleast 1 day. • Severe ADRs: Potentially life threatening, causes permanent damage or requires intensive medical treatment. • Lethal: Directly or indirectly contributes to death of the patient.
- 10. Drug idiosyncrasy" refers tountold reactions to drugs that occur in a small fraction of patients and have no obvious relationship to dose or duration of therapy. Definition
- 11. DRUG IDIOSYNCRAZY ● Itis genetically determined abnormal response to a drug. ● The drug interacts with some unique feature of the individual, not found in majority of subjects, and produces the uncharacteristic reaction. Example :- ● Chloramphenicol produces non dose-related serious aplastic anaemia in rare individuals. ● Barbiturates cause excitement and mental confusion in some individuals. ● Quinine causes cramps ,asthma ,diarrhoea, vascular collapse. ● Primaquine causes acute haemolytic anaemia.
- 12. Idiosyncratic drug reaction-Causes ●Genetic abnormality ● Deficiency of enzyme in the body ● Abnormal receptor activity ● Drug interaction with unique features
- 13. Genetic abnormality The occurrenceof an idiosyncratic reactions is dependent on the interaction between multiple genes and environmental factors
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- 15. Deficiency of enzymein the body ● Pseudocholinesterase deficiency ● Glucose 6 phosphate dehydrogenase deficiency Succinylcholine or Mivacurium Quinine, aspirin ,NSAID, sulfa drugs,
- 16. Abnormal receptor activity ●Activated receptors directly or indirectly regulate cell. Receptors are macromolecules involved in chemical signaling between chemical processes . 1. Ligand gated ion channel 2. G-protein coupled receptor 3. Enzyme linked 4. Nuclear receptors
- 17. Drug interaction withunique features ● Mechanism : 1. Pharmaceutical interaction 2. Pharmacokinetics interaction 3. Pharmacodynamics interaction
- 18. Alcohol idiosyncratic reaction unusualcondition that occurs when a small amount of alcohol produces intoxication that results in • Aggression, • Impaired consciousness, • Prolonged sleep, • Transient hallucinations, • Illusions, and • Delusions.
- 19. Detection of ADRs Pre-Marketing Studies Post– Marketing Surveillance Spontaneous adverse reaction reporting Epidemiological methods Case Control Studies Cohort Studies Phase 1 Phase 2 Phase 3
- 20. PRE- MARKETING STUDIES •AnimalModels •Risk information ,acute toxicity & which organs are affected . •Safety test •3 phases of clinical trails •Consequences
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- 22. •These methods areused to verify the link between drug exposure and an adverse outcome. •Two epidemiological methods most commonly used are: Cohort Studies Case Control Studies Epidemiological studies Advantage: Reveals unsuspected ADRs Advantage: Can be analysed quickly as number of patients analysed is small.
- 23. • Patient initials, •Ageat onset of reaction, •Reaction term(s), •Date of onset of reaction, • Suspected medication(s) • reporter information. Mandatory field for suspected ADR reporting form.
- 24. • • More rational Prescribing Better communication Considerrisk factors for ADRs Patient counseling Better monitoring of treatment 70% ADRs are potentially avoidable Preventing ADR
- 25. Medical maloccurrence ● Insome cases inspite of good medical attention and care ,an individual fail to respond properly or may suffer from adverse reactions of the drug . ● The injured person cannot get compensation ● Doctor was careful in selection of the drugs and has taken appropriate measures to overcome this effects.
- 26. Therapeutic misadventure Mischance oraccident or disaster ,in which individuals may be injuried or died due to some unintentional act of doctor or hospital . 3 types-therapeutic ,diagnostic , experimental It is known that many of the therapeutic procedure cause death to patient ,the doctor is not directly responsible for the harm. Radiological procedure(contrast) cause fatal adverse reactions
- 27. Contributory negligence ● Inthis condition patient is also responsible for the injury suffered by him.As such doctor is not the direct , cause of the injury suffered by the patient. ● Failure to give proper history ,cooperation,refusal to treatment ,against doctors advice .
- 28. References: •Goodnman& gilmans phamacologicalbasisoftherapeutics13 thedition •K.DTripathi–Essentialof pharmacology-6th edition •Lippincottillustratedreview–Pharmacology-6th edition •Bardalae principlesof forensicmedicicne& toxicology. •Anil Aggrawal textbookof forensicmedicineandtoxicology •Narayanareddy textbookof forensicmedicine andtoxicology
- 29. If you suspectan ADR do not assume someone else will report it……