Introduction to Adverse Drug Reactions (ADRs) – PST06211 Monitoring and Evaluation of Medicine Use
NTA Level 6 • Semester 2 • PST06211 Introduction to Adverse Drug Reactions (ADRs) Monitoring and Evaluation of Medicine Use • Source Session/Topic 12 Full source-text version: all educational wording from the extracted learning source is retained; only presenter/tutor metadata and web-layout noise are removed, while formatting is improved for readability. Session 12: Introduction to Adverse Drug Reactions (ADRs) Total Session Time: 120 minutes Prerequisites • None Learning Tasks By the end of this session students are expected to be able to: • Define ADRs • Explain the predisposing factors for ADRs • Classify ADRs • Explain each class of ADRs Resources Needed: • Flip charts, marker pens, and masking tape • Black/white board and chalk/whiteboard markers • Computer and LCD Projector SESSION OVERVIEW Activity/ Step Time Content Method 1 05 minutes Presentation Introduction to Learning Tasks 10 minutes Presentation 2 Definition of ADRS Buzzing 3 20 minutes Presentation Predisposing Factors for ADRs 20 minutes Presentation 4 Classification of ADRS Brainstorming 5 55minutes Presentation Explanations on each Class of ADRs 6 05 minutes Presentation Key Points 7 05 minutes Presentation Evaluation PST 06211 Monitoring and Evaluation of Medicines Use NTA Level 6 Semester 2 Facilitator Guide 91 SESSION CONTENTS STEP 1: Presentation of Session Title and Learning Tasks (5 minutes) READ or ASK students to read the learning objectives and clarify ASK students if they have any questions before continuing. STEP 2: Definition of ADRS (10 minutes) Activity: Buzzing (10 minutes) ASK students to pair up and buzz on the following question • What is Adverse drug reaction? ALLOW few pairs to respond and let other pairs to add on points not mentioned WRITE their response on the flip chart/board CLARIFY and SUMMARIZE by using the content below • Adverse drug reaction is a noxious and unintended reaction that occurs at a dose used for the treatment, diagnosis and prevention of disease, disorder or syndrome. • Side effects and ADRs are associated with drug use posing serious health consequences. Sometimes the word side effect and ADR are used alternatively but there is a clear difference between them. Side effect is often termed as type A ADR. • Sid effect is also an undesirable effect of drug and comes under ADR. STEP 3: Predisposing Factors for ADRs (20 minutes) • Age:The incidence of adverse drug reaction appears to be highest in the very young and very old people. In these two extreme periods of life, there is poorly developed and altered physiological function respectively. Therefore, metabolism and elimination of some drugs may be delayed. • Pathophysiological conditions:Diseases may alter the pharmacokinetic handling of a drug, its tissue sensitivity or the response to a drug. That is, diseases can alter drug absorption, metabolism, elimination and the body‘s response to drugs. • Amount of drug administered:An excessive response to drug or prolonged therapy may be a predisposing factor for ADRs. Over dosage is often relative rather than absolute because the individual response to a drug varies. PST 06211 Monitoring and Evaluation of Medicines Use NTA Level 6 Semester 2 Facilitator Guide 92 • Sex:several studies have shown that for some drugs women are more likely to suffer from ADRs than men. This is due to pharmacokinetic and or pharmacodynamic sex-related factors. • Previous history of allergy:Patients who have previously suffered an allergic drug reaction appear to be more susceptible than others to allergic ADRs in general. Heredity may make some people more susceptible to the toxic effects of certain drugs • Racial or Genetic Factors: There may be racial differences in the incidence of some type of ADRs or some individuals have a genetically determined response to development of ADRs. e. g. Ethno-pharmacological difference such as glucose 6-phosphate dehydrogenise deficiency, which predisposes to some drug induced haemolytic anaemia, is commoner amongst Africans. • Multiple Drug Therapy (Polypharmacy) The incidence of ADRs increases with the number of drugs given due to risk of interactions. Interaction between prescribed drugs is therefore an area, which is of concern to every health care professional. STEP 4: Classification of ADRS (20 minutes) Activity: Buzzing (5 minutes) ASK students to pair up and buzz on the following question for 2 minutes • What are classes of adverse drug reactions? ALLOW few pairs to respond and let other pairs to add on points not mentioned WRITE their response on the flip chart/board CLARIFY and SUMMARIZE by using the content below • There are four basic systems used to classify ADRs o Alphabetical or ABCDE system – by Rawlins and Thompson o According to intensity o Underlying mechanism mode o ADR according to frequency STEP 5: Explanations on each class of ADRs (55 minutes) • ABCDE SYSTEM – classify ADRs into five types o Type A („augmented―) These ADR are expected PST 06211 Monitoring and Evaluation of Medicines Use NTA Level 6 Semester 2 Facilitator Guide 93 They can be predicted on the base of pharmacodynamic properties of drug They depend on drug dose, they appear at higher doses Frequency is high > than 1% Mortality is low Therapy consists in dose adjustment e.g.: cough after ACEI, bleeding from GIT after NSAIDs, aspirin, corticoids o Type B (bizard―) Idiosyncratic reactions These ADR are not expected They can be hardly predicted Doesn´t depend on dose Occur in predisposed, intolerant patients – can be explained by rare genetic polymorphism, allergic reactions Frequency is low < than 0,1% Mortality is high o Type C continuous) This type of ADR increases number of ―spontaneous― diseases They occur usually after long-lasting administration They are often serious and persistent Mechanism of genesis is unclear They are unexpected, not predictable They can´t be verified experimentally e.g.: oral contraceptives and increased occurrence of thromboembolia. o Type D (delayed) Adverse effect may be presented years after a drug was used (years resp. generations) Teratogenity Carcinogenetic Mutagenity e.g.: cancer of vagina at daughters of