This document defines and describes various types of adverse drug reactions and events. It discusses pharmacovigilance, which is the science related to detecting, assessing, understanding, and preventing adverse drug effects. The document categorizes adverse drug effects into side effects, allergy reactions, toxicity, intolerance, idiosyncrasy, photosensitivity, dependence, withdrawal reactions, teratogenicity, mutagenicity, carcinogenicity, and drug-induced diseases. It provides examples and treatments for different types of reactions. Pharmacovigilance helps educate doctors about adverse drug reactions and regulates safe drug use.

1. BY
Prathyusha.k
Pharm D II Yr

2. ADVERSE DRUG REACTIONS:
A response to a drug which is noxious &
Unintended & which occurs at normal doses used
in man.
ADVERSE DRUG EVENTS:
Any untoward medical occurance that may present
during treatment with a pharmaceutical
product(drug),but which does not necessarily have
a causal relationship with this treatment.

3.  WHO defined it as the “science & activities related
to the detection,assessment,understanding &
prevention ofadverse effects or any other drug
related problems.”
 The information generated by pharmacovigilance is
useful in educating doctors about ADRs & in the
official regulation of drug use.
 It has important role in rational use of medicines &
assessing safety of medicines.

4. ADRs can be minimised but not eliminated by
observing the following practices:
 Avoid all inappropriate use of drugs in the context
of patient’s clinical condition.
 Use correct dose,route & frequency of drug
administration based on patient’s specific
variables.
 Take into consideration about previous history of
drug reactions,allergic diseases &exercise
caution(drug allergy is more common in allergic
patients)

5.  Rule out possibility of drug interactions
when more than one drug is prescribed.
 Adopt correct drug administration technique
(eg:iv inj of vancomycin must be slow).
 Carry out appropriate laboratory monitoring
(serum drug levels with lithium).
SEVERITY OF ADVERSE DRUG REACTIONS:
Minor:No therapy,antidode or prolongation of
hospitalization is required.
Moderate:Requires change in drug therapy,specific
treatment or prolongs hospital stay atleast one
day.
Severe:Potentially life threatening,causes
permanent damage/requires intensive medical
treatment.
Lethal:Directly/indirectly contributes to death of
the patient.

7. Adverse drug effects may be categorized into:
1).Side effects:
Unwanted & unavoidable p’dynamic effects occurs
at therapeutic doses.
 Reduction of dose generally ameliorates the
symptoms.
 Side effects may be based on same action as the
therapeutic effect.
eg;Atropine is used as preanaesthetic for its
antisecretory action,the same action produces
dryness of mouth as side effect.
 Many drugs have been developed from observation
of side effects.eg;sulfonamides(antibacterial) used
as hypoglycemic sulfonylureas.

8.  These are indirect consequences of a primary
action of drug.
Eg;corticosteroids weekens host defence
mechanisms so that latent TB gets activated.
3).Toxic effects:
 Due to excessive p’cological action of the drug
due to overdose & prolonged use.The effects are
predictable & dose related.
 They result from functional alteration(high dose of
ATROPINE causes DELIRIUM)or drug induced tissue
damage(Hepatic necrosis from PARACETAMOL
overdose).

9. Poisoning:
 Due to large doses of drugs.
 Poison endangers life by severely affecting one or
more vital functions.
MEASURES:
 Resuscitation & maintenance of vital functions:
Adequate ventilation,artificial respiration,
maintenance of BP,heart beat,body temperature
& blood sugar level.
 Termination of exposure:
Removing patient to fresh air,washing skin &
eyes,induction of emesis with syrup ipecac/gastric
lavage [avoided in kerosine & CNS poisoning]

10.  Prevention of absorption of ingested poisons:
 20-40g(1g/kg) of activated charcoal suspension
should be administered in 200ml of water.
 Strong acids& alkalies,metallic salts,iodine,
cyanides,alcohol,organic solvents are not adsorbed
by charcoal.
 Hastening elimination:
Quick removal of poison from the body by
haemodialysis,inducing diuresis/altering urinary
pH.

11. 4).Intolerance:
known as inability to withstand/consume the drug.
Eg;only few doses of carbamazepine may cause
ataxia in some people.
5).Idiosyncrasy:
It is genitically determined abnormal reactivity to a
chemical.Peculiar to an individual because the drug
reacts with the specific gene which is specific to an
individual.
Eg;Barbiturates causes excitement & mental
confusion in some individuals.

12. 6).Drug allergy:
 A medical condition that makes a individual to
feel ill when a drug is taken.
 Allergic reactions occur only in a small proportion
of the population exposed to the drug & cannot be
produced in other individuals.
 Occur even with smaller doses & have a different
time course of onset & duration,also called as
HYPERSENSITIVITY but not supersensitivity.
 The drug/its metabolites acts as AG/HAPTEN &
induce production of AB/sensitized lymphocytes.
 They are of two types:HUMORAL & CELLMEDIATED.

13. A. HUMORAL:
 TYPE-I(anaphylactic)REACTIONS:
On exposure to the drug,AG:AB reaction takes
place on the mast cell surface releasing mediators
likehistamine,5HT,leukotrienes Prostaglandins
etc.,resulting in itching,
angioedema,bronchospasm,rhinitis.
 TYPE-II(cytolytic)REACTIONS:
Drug+component of a specific tissue cells act
as AG.The resulting antibodies(IgG,IgM)bind to the
target cells on reexposure AG:AB reaction takes
place on the surface of these cells,complement is
activated and cytolysis occurs.

14.  TYPE-III(retarded)REACTIONS:
AG:AB complexes bind complement & precipitate
on vascular endothelium giving rise to a destructive
inflammatory response.
Manifestations are rashes,serum sickness,mental
symptoms,myocarditis,
nephritis(usually in 1-2weeks)
B.CELL MEDIATED:
 TYPE-IV(delayed hypersensitivity)REACTIONS:
These are mediated through production of
sensitized T-lymphocytes carrying receptors for the
AG.They form inflammatory response.
Eg:dermatitis,rashes,fever,photosensitization
takes>12hrs to develop.

15. TREATMENT:
 Administration of oxygen.
 0.5mg adrenaline i.m injection.
 Administer a H1 antihistaminic i.m/slow i.v.
 I.V of glucocorticoids should be added in many
cases.
 Adrenaline followed by a short course of
glucocorticoids is indicated for bronchospasm
attending drug hypersensitivity.Glucocorticoids are
the only drug in type II,III,IV reactions.

16. 7).Photosensitivity:
It is a cutaneous reaction resulting from drug
induced sensitization of the skin to Uvrays.the
reactions are of two types:
a) Phototoxic:
Drugs/its metabolites accumulates in the
skin,absorbs light & undergoes a photochemical
reaction followed by a photobiological reaction
resulting in local tissue
damage.[edema,blistering etc drugs involved are
tetracyclines,thiazides]
b) Photoallergic:
Rarely AB mediate photoallergy & the
reaction takes form of flare&wheal on exposure
to sun drugs involved are
sulfonamides,chloroquines etc.

17. 8).Drug dependence:
It is a state in which use of drugs for personal
satisfaction is accorded a higher priority than
other basic needs,often in the face of known risks
to health.
a].Psychological dependance:individual believes
optimal state of wellbeing is achieved only
through the actions of the
drugs[cocaine,opioids,BZPs].
b].Physical dependance:an altered physiological
state produced by repeated administration of a
drug which necessitates the continued presence
of the drug to maintain physiological equilibrium.
 Discontinuation of the drug leads to withdrawl
syndrome.[BZDs,alcohol,cocaine].

18. c].Drug abuse:social disapproval of the manner
& purpose of drug use.
d].Drug addiction:strong physiological &
psycological dependence on a drug.
Eg;Narcotics,cocaine,Amphetamines.
e].Drug habituation:a psychological dependence
on drug due to repeated consumption with a
desire to continue its use,withdrawal produces
only mild discomfort.
Eg:coffee,tea,social drinking.

19. 9).Drug withdrawal reactions:
These reactions are produced when there
is sudden cessation of the drug or
interruption of therapy with certain other
drugs.
Eg;precipitation of MI may result from stoppage
of beta blockers.
10).Teratogenicity:
It refers to capacity of a drug to cause
foetal abnormalities when administered to the
pregnant mother.
Eg; Anticancer drug-cleft palate,multipledefects
Warfarindepressed nose,growth
retardation.

20. 11).Mutagenicity & Carcinogenicity:
The capacity of a drug to cause genitic
defects &cancer respectively.Usually oxidation of
the drug results in the production of reactive
intermediates which effects genes & may cause
structural changes in the chromosomes.
Eg;anticancerdrugs,tobacco,estrogens,radioisotope
s.
12).Drug induced diseases:
These are iatrogenic(physician
induced)diseases & functional
distrubances(disease)caused by drugs which
persists even after the offending drug has been
withdrawn & largely eliminated.
eg:peptic ulcer by salicylates & corticosteroids.

21.  If a new drug causes a bizarre effect in 1
in 6000 patients it would need 18000
patients to use the drug for it to occur in
3 patients
 It would take twice as many before there
was any suspicion that the effect was due
to the drug
 If the effect also occurs naturally then it
would take many times more patients
 Most early trials involve about 2000
patients

22.  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
 Established drugs

26. References
 www.authorstream.com
 http://www.google.co.in/images
 Essentials of Medical pharmacology by K.D Tripathi
pg;no :78-86