4.2.1 Pharmacovigilance Flashcards
What is pharmacovigilence?
Science and activites relating to detection, assessment, understanding and prevention of adverse effects or any other possible drug-related problem
Why is pharmacovigilence important?
Enhance patient care and safety
Support public health programs by providing reliable information for the effective assessment of risk-benefit profilfe of medicines
What is the agency for pharmacovigilence in the UK?
MHRA
Pharmaceutrical companies need to get permission when they want to license medicines
What is the most common clinical adverse event?
Drug reaction
6.5% of hospital admissions
15% of patients in hospital
Why are ARDs important?
Uses resources when it is avoidable
What was thalidomide used for initially?
Sedative and given for morning sickness in pregnant women
Why did thalidomide cause phocomelia or limb malformation?
R-enantiomer has sedative effects
S-enantiomer is teratogenic
How many people were affected by thalidomide?
10,000 babies
2000 deaths
Identified in Germany but link was not made, thought to be environmental
What was learnt from thalidomide?
Adequate testing
Government regulation
Reporting systems
Implications of unfounded claims
Most medicines DO cross the placenta
Avoidance of unncessary drug use in pregnancy
How many cases are required for drug investigation?
10
What is thalidomide used for today?
Cancer and leprosy
If given to women, must ensure they know they cannot become pregnant
When are ADRs identifed?
70% ADRS based on known pharmacokinetics and dynamics
Removed from market if ADRs are serious enough/common
Why is it difficult to identify ADRs?
When opening up drugs to entire populations more likely to get an ADR as a trial can only test on a limited number of people
When are ADRs classified as serious?
Fatal
Life-threatening
Prolonged hospitalisation
Long-term disability
Congenital abnormalities
What is the difference between adverse drug reactions and events?
Adverse drug event- injury that occurs during treatment, not necessarily due to drug
Adver drug reaction- response to drug which is noxious and unintended, occurring at doses normally used in man
Fill in the table
What is the usual nature and mechanism of ADRs?
Mimic disease or syndrome that occurs naturally
May have non-therapeutic causes
Some syndroms causaility solely due to therapeutic agents
e.g. Fibrosing colonpathy, large doses of pancreating enzymes used in treating children with CF
What are the 4 broad mechanisms of action for an ADR?
Exaggerated response
Desired pharmacological effect at alternative/additional site (GTN –
headache)
Additional/secondary pharmacological effect (QT length)
Triggering an immunological response (anaphylaxis)
Why do we need pharmacovigilence?
Clinical trials are limited:
Population
Timescale
Dose
Conditions
Concomitant illness and therapy
Limited ability to identify low-frequency adverse events or long-term side effects
What does detection in a clinical trial depend on?
Number of patients required to be 95% sure of detecing an ADR depends on predicted incidence
Basically if an ADR is rare would need huge amounts of people to see, if something is 1/1000, would need 3000 people
Why is reporting ADRs so important?
Leads to further questioning
What is the Yellow card scheme?
System to report ADRs for recently introduced products
Accessible by everyone, all suspected ADRs including minor ones, all reactions to vaccines
Established products, serious or unusual suspected reactions
How do you know if a drug is new under the yellow card scheme?
Black triangle pointing down
