This document discusses adverse drug reactions (ADRs), which are unwanted effects that occur when taking medications. It notes that ADRs are a major cause of hospital admissions and deaths. ADRs are more common in elderly patients due to multiple medications, health issues, and altered drug metabolism. ADRs can be type A, which are dose-dependent and predictable, or type B, which are unpredictable and idiosyncratic. The document emphasizes that carefully selecting drugs and dosages based on a patient's individual characteristics can help reduce the risks of ADRs. Monitoring programs work to detect ADRs and improve drug safety.

1. Adverse Drug Reactions
Presented to: Mam Fatima Saqib
Presented by: Sameen Rashid
Roll no: 13

2. Warfarin, Insulin and Digoxin are
the most Dangerous drugs in the
elderly.
Do we believe that?

3. All Drugs are
Dangerous
No Drugs are
Dangerous if
used properly
How dangerous a drug is
depends on the skill of the
prescriber
The most
dangerous
drugs have the
greatest
potential for
benefit
Some drugs are
dangerous in
acute poisoning
but not when
used
therapeutically
Some drugs
have a low
therapeutic
ratio
Some drugs have
a low incidence of
horrendous
effects
Some adverse
effects can be
predicted if you
know the
pharmacology
(Type A); some
are not (Type B)
Some adverse
effects occur
after a delay
or after
stopping
BAD
GOOD

4. RISK BENEFIT
When prescribing drugs a doctor must assess
risk to benefit ratio in the individual patient by
•Choosing an appropriate class of drug then an
appropriate individual agent
•Is it effective ?
•What are the chances of adverse effect ?
•Are there features in this patient which
affect choice eg other drugs, organ failure,
aged
•Tailoring the dose
•Considering duration of treatment
The Risk to Benefit Ratio

5. Adverse drug reactions
“Any response to a drug which is
noxious, unintended and occurs at doses
used for prophylaxis, diagnosis or
therapy.”
An ADR is any unwanted effect resulting
from a drug’s use in treatment.

6.
Epidemiology
4% of hospital admissions
1 in 1000 deaths in medical wards
10 to 20 % of in-patients
5% of patients in general practice

7. More frequent in elderly:
erratic drug taking
multiple pathology
altered pharmacokinetics
increased sensitivity of CNS and
CVS

8. Mechanisms
Common mechanisms are:
 Abnormal pharmacokinetics due to
genetic factors
comorbid disease states
 Synergistic effects between either
a drug and a disease
two drugs

10. Drugs
 Anti-coagulants
 NSAIDs
 Corticosteroids
 Anti-hypertensives
 Anti-biotics
 Diuretics
 Insulin

11. Occur in circumstances related to
Drug’s pharmacology
Predisposing factors in the patient
Care taken in choosing the drug
The dose.

12. Location
Local effect
limited to a certain location
Systemic effects
Throughout the systemic circulation
ocular antihypertensives administered locally as
eye drops to the systemic circulation.

13. Classification
 Type A: Augmented pharmacologic effects
 Type B: Idiosyncratic

14. Type A: Augmented
pharmacologic effects
 dose dependent
 Predictable
 constitute approximately 80% of adverse drug reactions
 Are either due to excessive action at targeted receptor or to action
at a non-target receptor
 Are closely related to amount of drug in the body
 usually a consequence of the drug’s primary pharmacological
effect (e.g. bleeding when using the anticoagulant warfarin) or a
low therapeutic index of the drug (e.g. nausea from digoxin)
 usually mild, although they may be serious or even fatal
 usually due to inappropriate dosage
 Can be avoided with care

15. Type B: Idiosyncratic
 This effect is unrelated to established pharmacological
effects
 The effect may be serious organ damage
 There is a poor relationship to dose
 Uncommon
 Difficult to detect in drug development
 Cannot be avoided
 Patient idiosyncrasy is a major factor

17. Monitoring bodies
WHO Uppsala Monitoring Centre
Pakistan Pharmacovigilance Programme of
Pakistan (PvPP)
European Union European Medicines Agency (EMEA)
United States Food and Drug Administration (FDA)
Canada Marketed Health Products Directorate of
Health Canada
Australia Therapeutic Goods Administration (TGA)

18. Detecting Adverse Effects
 MRHA (Medicine and Healthcare products
Regulatory Agency) freephone service for reporting
and information about suspected ADRs
 Self reporting by patients and relatives using
Yellow cards available at pharmacies
 Prescription event monitoring
 New drugs – black triangles and yellow cards

23. Measuring danger
 MHRA activity
through Yellow
card reporting
and prescription
monitoring
 Huge increase
in reports over
recent years

25. Who reports to the MHRA?
•Under-reporting estimated at 94% in hospital practice (Smith et al
1996)
•MRHA activity good at detecting adverse effects
•Not very good at assessing the risk ratio

26. Prevention of Adverse Drug
reactions
 Never use any drug unless there is good
indication. If the patient is pregnant do not use
the drug unless the need is imperative.
 Allergy and idiosyncrasy are important causes
of ADRs. Ask if the patient had previous
reactions.
 Ask if the patient is already taking other drugs
including self medication

27. Preventing ADRs
 Age, hepatic and renal disease may impair
clearance of drugs so smaller doses may be
needed.
 Genetic factors may also predispose to certain
ADRs
 Prescribe as few drugs as possible and give
clear instructions
 Where possible use familiar drugs. With new
drugs be particularly alert for ADRs and
unexpected event.
 If serious ADRs are liable to occur warn the
patient

28. Some websites
 Clinical pharmacology and therapeutics by roger walker
 www.yellowcard.gov.uk
 http://medicines.mhra.gov.uk
 www.dsru.org
 http://eis.bris.ac.uk/~pmcjcr/Drug%20Safety.pdf
 www.Wikipedia.com