3. Introduction
Adverse effect any undesirable consequence of
drug administration
Adverse drug reaction any noxious change due
to a drug occurs at doses normally used in man
requires treatment or decrease in dose or indicates
caution in the future use of the drug
4. Incidence and severity
Patient characteristics age, sex, ethnicity, coexisting
disorders, genetic or geographic factors
Drug factors type of drug, administration route,
treatment duration, dosage, bioavailability
5.
6. Pharmacovigilance
Science and activities relating to the direction,
assessment, understanding and prevention of
adverse effects or any other drug related problems
7. Classification of ADRs
Type of reaction: Type A (Augmented), B (Bizarre),
C(Chemical),D (Delayed), E (Exit), F (Familial), G (Genotoxicity),
H (Hypersensitivity), U (Un classified)
Severity: Minor, Moderate, Severe, Lethal ADRs
Others: Side effects, Secondary effects, Toxic effects,
Intolerance, Idiosyncrasy, Drug allergy, Photosensitivity, Drug
Dependence, Drug Withdrawal Reactions, Teratogenicity,
Mutagenicity, Carcinogenicity, Drug induced disease
(Iatrogenic)
8. Severity
Minor no therapy, antidote or prolonged
hospitalisation required
Moderate requires change in drug therapy,
specific treatment and prolongs hospital stay
Severe potentially life threatening, causes
permanent damage or requires intensive medical
treatment
Lethal directly or indirectly contributes to death of
patient
9. Classification of ADRs....
Wills and Brown
Type A (Augmented)
Type B (Bizarre)
Type C (Chemical)
Type D (Delayed)
Type E (Exit/End of treatment)
Type F (Familial)
Type G (Genotoxicity)
Type H (Hypersensitivity)
Type U (Un classified)
10. Type A (Augmented) reactions
Reactions which can be predicted from the known
pharmacology of the drug
Dose dependent
Can be alleviated by a dose reduction
Anticoagulants Bleeding
Beta blockers Bradycardia
Nitrates Headache
Prazosin Postural hypotension
11. Type B (Bizarre) reactions
Cannot be predicted from the pharmacology of the
drug
Not dose dependent,
Host dependent factors important in predisposition
Penicillin Anaphylaxis
Anticonvulsant Hypersensitivity
12. Type C (Chemical) reactions
Biological characteristics can be predicted from the
chemical structure of the drug/metabolite
Paracetamol Hepatotoxicity
13. Type D (Delayed) reactions
Occur after many years of treatment.
Can be due to accumulation.
Chemotherapy Secondary tumours
Phenytoin during pregnancy Teratogenic effects
Antipsychotics Tardive dyskinesia
Analgesics Nephropathy
14. Type E (End of treatment)
reactions
Occur on withdrawal especially when drug is stopped
abruptly
Phenytoin withdrawal Seizures,
Steroid withdrawal Adrenocortical insufficiency.
15. Type F (Familial)
Occurs only in genetically predisposed
G6PD deficiency primaquine haemolytic
anaemia
17. Categories
1) Side effects
2) Secondary effects
3) Toxic effects
4) Poisoning
5) Intolerance
6) Idiosyncrasy
7) Drug allergy
8) Photosensitivity
9) Drug dependence
10) Withdrawal reactions
11) Teratogenicity
12) Mutagenicity and carcinogenicity
13) Drug induced diseases
18. Side effects
Unwanted unavoidable pharmacodynamic effects at therapeutic
doses
Based on same action atropine causes dryness of mouth
Based on different action promethazine causes sedation
Therapeutic in one context side effect in other codeine causes
constipation which is used therapeutically in traveller’s diarrhoea
Drugs developed by observation of side effects sulphonamides
causes hypoglycaemia now used as OHA
19. Secondary effects
Indirect consequence of a primary action of the
drug
Suppression of bacterial flora by tetracyclines
superinfections
20. Toxic effects
Excessive pharmacological action of the drug
overdosage/prolonged use
Absolute accidental/suicidal/homicidal
Relative usual dose of gentamycin in renal failure patients
Extended therapeutic effect barbiturates causing coma
Another action morphine causing respiratory failure
21. Poisoning
Large doses of the drugs
Endangers life by severely affecting one or more
vital functions
Specific antidotes are available for some drugs
22. Intolerance
Toxic effects at therapeutic doses
Low threshold of the individual to the action of the
drug
Carbamazepine ataxia
Chloroquine vomiting, abdominal pain
23. Idiosyncrasy
Genetically determined abnormal reactivity to a chemical
Interacts with some unique feature off the individual
uncharacteristic action
Barbiturates excitement and mental confusion
Quinine/quinidine cramps, diarrhoea
Chloramphenicol aplastic aneamia
24. Drug allergy/hypersensitivity
Immunologically mediated reaction symptoms
unrelated to the pharmacodynamic profile of the
drug
Occurs even at smaller doses
Different time course of onset and duration
Prior sensitisation is needed
Latent period 1-2 weeks
Drug or its metabolite acts as an antigen or hapten
and induce production of antibodies
28. Photosensitivity
Cutaneous reaction drug induced sensitization of skin
to UV radiation
Phototoxic - drug/metabolite accumulates
photochemical reaction photobiological reaction
tissue damage, i.e. erythema, oedema, blistering,
hyperpigmentation and desquamation. Tetracyclines, tar
products
Photoallergic – drug/metabolite cell mediated
immune response exposure to UV popular or
eczematous contact dermatitis. Sulphonamides,
griseofulvin, chloroquine
29. Drug dependence
Alters mood and feelings
Repetitive use euphoria, withdrawal from reality,
social adjustment
Use of drugs for personal satisfaction given higher
priority
30. Psychological dependence
Optimal state of well being action of the drug
Intensity varies from desire to craving
Reinforcement ability of the drug to produce
effects that make the user wish to take it again or to
induce drug seeking behaviour
Strong reinforcers opioids, cocaine
Weak reinforcers benzodiazeoines
31. Physical dependence
Altered physiological state repeated
administration of a drug which necessitates
continued presence of the drug to maintain
physiological equilibrium
Discontinuation withdrawal syndrome
Opioids, barbiturates, alcohol, benzodiazepines
32. Drug abuse
Use of a drug by self medication
Deviates from the approved medical and social
patterns
Social disapproval of the manner and purpose of
drug use
33. Drug addiction
Compulsive drug use
Overwhelming involvement with the use of a drug
Relapse is common
Amphetamines, cocaine, cannabis, LSD
Most have little or no physical dependance
34. Drug habituation
Less intensive involvement with the drug
Withdrawal produces only mild discomfort
Tea, coffee, tobacco, social drinking
Physical dependence absent
35. Drug withdrawal reactions
Sudden interruption of therapy with certain drugs
adverse consequences
Worsening of clinical condition mostly
Abrupt cessation of corticosteroid therapy acute
adrenal insufficiency
Clonidine severe hypertension, restlessness and
sympathetic overactivity
β blockers worsening of angina, precipitation of MI
Minimised by gradual withdrawal
36. Teratogenicity
Capacity of a drug to cause foetal abnormalities
when administered to a pregnant mother
Fertilisation and implantation conception – 17
days failure of pregnancy
Organogenesis 18 – 55 days deformities (most
vulnerable period)
Growth and development 56 days onwards
developmental abnormalities
37.
38.
39. Mutagenicity and carcinogenicity
Capacity of a drug to produce genetic defects and
cancer
Covalent interaction with DNA mutations
When the modified DNA sequences code factors
like protooncogenes cancer or tumour
Chemical carcinogenesis without interacting with
DNA, takes 10-40 years to develop
Anti cancer drugs, radioisotopes, oestrogen,
tobacco
40. Drug induced
diseases(Iatrogenic)
Functional disturbances caused by drugs
Persists even after the offending drug has been
withdrawn
Salicylates and corticosteroids peptic ulcer
Antipsychotics parkinsonism
Isoniazid hepatitis
Hydralazine DLE
41. Prevention
Avoid inappropriate use
Appropriate dose, route and frequency
h/o drug reactions
h/o allergic disease
Drug interactions
Administration technique
Lab monitoring