WHO-UMC Causality categories

Causality assessment of ADRs is a system used for estimating the strength of relationship between medicines exposure and circumstance of adverse responses

 • Causality assessment of ADRs may be accepted by clinicians, academics, the pharmaceutical industries and controllers, and in different settings, including clinical trials.

Data demanded for reason assessment. 

• All drugs near the time of the event – dates – doses – suggestions 

• The event description – date of onset – duration to onset – event wordbook term

 Results of dechallenge & rechallenge. 

• outgrowth of the event

 • Case medical history – history conditions of significance eg hepatitis – 0ther current conditions(co-morbidities) eg • tuberculosis • diabetes.

 Causality assessment need. 

• Problem in pharmacovigilance is that utmost case reports concern suspected adverse medicine responses.

 • In practice many adverse responses are certain or doubtful utmost are nearly in between these extremes, i.e possible or probable.

 • In an attempt to break this problem numerous systems have been developed. 

• Causality assessment has come a common routine procedure in pharmacovigilance. 

WHO- UMC CAUSALITY ASSESSMENT SYSTEM

 • It has been developed in discussion with the National Centers sharing in the Programme for International Drug Monitoring and is meant as a practical tool for the assessment of case reports. • It's principally a combined assessment taking into account the clinical- pharmacological aspects of the case history and the quality of the attestation of the observation. 

• This system gives guidance to the general arguments which should be used to elect one order over another.

 Causality assessment of ADRs reported in ICSRs attained with WHO- UMC criteria was distributed into certain, probable, possible, doubtful, unclassified, and unclassifiable. also, in the Naranjo algorithm, ADRs were distributed into definite, probable, possible, and doubtful.

 This system includes the following 4 criteria

 1. Time connections between the medicine use and the adverse event. 

2. Presence Absence of other contending causes (specifics, complaint process itself). 

3. Response to medicine pullout or cure reduction (dechallenge).

 4. Response to medicine readministration (rechallenge).

Who uses causuality assesment sacles and why?

 Informal reason assessment of ADRs is in general practice by healthcare professionals to conclude opinions regarding remedy operation. Algorithms should give further objective decision on reason rather than theoretical explanation in relating adverse events during remedy.

 Basic languages in WHO- UMC Causality Assessment scale

 • Challenge: Giving of the medicine to the case during the AE or treatment.

 • Dechallenge: Stopping of the medicine, generally after an adverse event (AE) or at the end of a planned treatment. Dechallenges may be complete or partial, i.e the medicine is completely stopped or dropped in cure and the AE may completely vanish or only incompletely drop. 

• Positive dechallenge: AE disappears after the stopping of the medicine.

 • Negative dechallenge: This refers to the AE does not vanish after the stopping of the medicine. 

• Rechallenge: resuming of the same medicine after having stopped it, generally for an AE. Rechallenges may also be complete or partial. 

• Negative rechallenge: This is the case where the AE doesn't reoccur after the medicine is renewed. Positive rechallenge AE recurrs after resuming the medicine.

 • Prechallenge : This is a new term that refers to the use of the same medicine at some point in the past.

 Adr reporting demand 

• Case information

 • Adverse medicine information 

• medicine information

 • Health care professional information

 The Use of the WHO- UMC system

It can be lifesaving or helpful in precluding the farther damage caused by the medicine to our body systems. 

Estabilishing a relationship of casuality between the drug entered and the events passed exercising reason assesment is demanded to reduce the occurence of adverse medicine responses and to help exposure of cases towards fresh medicine hazards.

 The generally used scale for reason establishment of ADR? Scoring for Naranjo algorithm> 9 = definite ADR; 5 – 8 = probable ADR; 1 – 4 = possible ADR; 0 = doubtful ADR.

 The Naranjo algorithm

Written by: Khuba Raniya

Pharm D

Student ID: 208/1222