Who causality assessment scale

complete description of causality assessment with the definition of basic terminologies.& relation with an adverse event and adverse drug reaction, causality terms & assessment criteria.

1. WHO CAUSALITY ASSESSMENT SCALE PRESENTED BY: SHARIQUE RAZA M.PHARM 2 nd SEM PHARMACY PRACTICE JAMIA HAMDARD 1

2. Definition Pharmacovigilance: Pharmacovigilance (PV) is defined as the science and activities relating to the detection, assessment, understanding and prevention of adverse effects or any other drug-related problem. Adverse drug reaction: A response to a drug which is noxious and unintended, and which occurs at doses normally used in man for the prophylaxis, diagnosis, or therapy of disease, or for the modifications of physiological function'. 2

3. Adverse drug event: Any new clinical experience that occurs after commencing a medicine, not necessarily a response to a medicine, and is recorded without judgement on its causality. 3

4. Adverse drug event causality assessment Adverse drug reactions 4

5. Causality assessment of ADRs is a method used for estimating the strength of relationship between drug(s) exposure and occurrence of adverse reaction (s ). Causality assessment of ADRs may be undertaken by clinicians, academics, the pharmaceutical industry and regulators, and in different settings, including clinical trials. 5

6. Data needed for causality assessment All medicines near the time of the event dates doses indications The event description date of onset duration to onset event dictionary term 6

7. Results of dechallenge & rechallenge Outcome of the event Patient medical history past diseases of importance eg hepatitis 0ther current diseases (co-morbidities) eg tuberculosis diabetes 7

8. Causality assessment need P roblem in pharmacovigilance is that most case reports concern suspected adverse drug reactions. In practice few adverse reactions are certain or unlikely most are somewhere in between these extremes, i.e. possible or probable . In an attempt to solve this problem many systems have been developed . C ausality assessment has become a common routine procedure in pharmacovigilance 8

9. WHO-UMC CAUSALITY ASSESSMENT SYSTEM It has been developed in consultation with the National Centers participating in the Programme for International Drug Monitoring and is meant as a practical tool for the assessment of case reports. It is basically a combined assessment taking into account the clinical-pharmacological aspects of the case history and the quality of the documentation of the observation. This method gives guidance to the general arguments which should be used to select one category over another 9

10. This method includes the following 4 criteria: Time relationships between the drug use and the adverse event. Presence/Absence of other competing causes (medications, disease process itself). Response to drug withdrawal or dose reduction (dechallenge). Response to drug readministration ( rechallenge ). 10

11. Basic terminologies in WHO-UMC Causality Assessment scale Challenge: Giving of the drug to the patient during the AE or treatment. Dechallenge: Stopping of the drug, usually after an adverse event (AE) or at the end of a planned treatment. Dechallenges may be complete or partial, i.e. the drug is fully stopped or decreased in dose and the AE may fully disappear or only partially decrease. Positive dechallenge: AE disappears after the stopping of the drug. Negative dechallenge: This refers to the AE doesn't disappear after the stopping of the drug 11

12. Rechallenge: Restarting of the same drug after having stopped it, usually for an AE. Rechallenges may also be complete or partial. Negative rechallenge : This is the case where the AE does not recur after the drug is restarted. Positive rechallenge : AE recurrs after restarting the drug. Prechallenge : This is a new term that refers to the use of the same drug at some point in the past. 12

13. The various causality categories and the assessment criteria of the various categories are: 1) Certain • Event or laboratory test abnormality, with plausible time relationship to drug intake • Cannot be explained by disease or other drugs • Response to withdrawal plausible (pharmacologically, pathologically) • Event definitive pharmacologically or phenomenologically (i.e. an objective and specific medical disorder or a recognised pharmacological phenomenon) • Rechallenge satisfactory, if n ecessary 13

14. 2) Probable /Likely Event or laboratory test abnormality, with reasonable time relationship to drug intake Unlikely to be attributed to disease or other drugs Response to withdrawal clinically reasonable Rechallenge not required 14

15. 3)Possible Event or laboratory test abnormality, with reasonable time relationship to drug intake Could also be explained by disease or other drugs Information on drug withdrawal may be lacking or unclear 15

16. 4) Unlikely Event or laboratory test abnormality, with a time to drug intake that makes a relationship improbable (but not impossible) Disease or other drugs provide plausible explanations 16

17. 5)Conditional /Unclassified Event or laboratory test abnormality More data for proper assessment needed, or Additional data under examination 17

18. 6) Unassessable /Unclassifiable Report suggesting an adverse reaction Cannot be judged because information is insufficient or contradictory Data cannot be supplemented or verified 18

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20. Adr reporting requirement Patient information Adverse drug information Drug information Health care professional information 20

21. REFERENCES https://www.who-umc.org/media/2768/standardised-case-causality-assessment http://www.who.int 21

22. THANK YOU 22