DRUG REACTIONS
A drug may be defined as a chemical
substance, or combination of substances,
administered for the investigation, prevention
or treatment of diseases or symptoms, real or
imagined.
The distinction between drugs and 'other
chemicals' is not always easily
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Chemicals of very diverse structure are increasingly
added to foods and beverages as dyes, flavours or
preservatives.
Chemicals used in agriculture or in veterinary medicine
may contaminate human
Advent of therapeutic agents that may be useful for
improving the appearance, e.g minoxidil for
androgenetic alopecia and tretinoin for photo-aged skin,
the distinction between drugs and cosmetics has
become blurred
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An adverse drug reaction - defined as an undesirable
clinical manifestation resulting from administration of
a particular drug at doses normally used for
prophylaxix,diagnosis & threapy of diseases –WHO 1972
this includes reactions due to overdose, predictable
side-effects and unanticipated adverse
manifestations.
Adverse drug reactions are the inevitable price we pay
for the benefits of modern drug therapy.
They are costly both in terms of the human illness caused
in economic terms,
can undermine doctor-patient relationship.
Adverse drug reactions contribute to the need
for hospitalization in 10-17% of elderly
inpatients
 Inappropriate medication is a major cause of
adverse drug reactions in elderly patients;
 27% of elderly patients on medication admitted
to a teaching hospital experienced adverse
drug reactions,
 Adverse drug reactions occur in between 6 and
17% of children admitted to specialist
paediatric hospitals
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The incidence of adverse drug reactions varies
from 6 to 30%, with at least 90 million courses of
drug treatment given yearly
 The reported percentage of patients who develop
an adverse drug reaction during hospitalization
varies markedly from 1.5 to 44%,
 Although in most studies the incidence is about
10-20%
 It has been estimated that about one in 40
consultations in general practice is the result of
adverse drug reactions.
 the percentage of consultations involving an
adverse drug reaction increased from 0.6% for
patients aged 0-20 years to 2.7% for patients aged
over 50 years
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The elderly persons have a significantly higher
incidence of adverse drug reactions, related to
decreased organ reserve capacity
 Altered pharmacokinetics and
pharmacodynamics,
 polypharmacy
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CLASSIFICATION OF ADVERSE DRUG
REACTIONS.
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Non-immunological
Predictable
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Overdosage
Side-effects
Cumulation
Delayed toxicity
Facultative effects
Drug interactions
Metabolic alterations
Teratogenicity
Non-immunological activation of effectors pathways
Exacerbation of disease
Drug-induced chromosomal damage
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Unpredictable
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Intolerance
Idiosyncrasy
IMMUNOLOGICAL (UNPREDICTABLE)
IgE-dependent drug reactions
 Immune complex-dependent drug reactions
 Cytotoxic drug-induced
 Cell-mediated reactions
 Miscellaneous
 Jarisch-Herxheimer reactions
 Infectious mononucleosis-ampicillin reaction
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IMMUNOLOGICAL DRUG REACTIONS
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IgE-dependent (type I) drug reactions:
urticaria and anaphylaxis
Antibody-mediated (type II) drug reactions
Immune complex-dependent (type III)
Vasculitis
The Arthus reaction
Cell-mediated reactions (type IV reactions)
Erythema multiforme
Stevens-Johnson syndrome“
Toxic epidermal necrolysis“
"Lichenoid drug eruptions
Lupus erythematosus (LE)-like syndrome induced by drugs
Drug-induced pemphigus &Pemhigoid
Fixed drug eruptions
DRUGS CAUSING EXANTHEMATIC REACTIONS.
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Ampicillin and penicillin
Cephalosporins
Phenylbutazone and other pyrazolones
Barbiturates
Sulphonamides
Thiazides
Phenytoin
Naproxen
Carbamazepine
Isoniazid
Gold
Phenothiazines
Gentamicin
EXANTHEMATOUS REACTIONS
EXANTHEMATOUS REACTIONS
URTICARIA OR ANAPHYLAXIS
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Drugs causing are
Animal sera
Dextrans
Antibiotics
Angiotensin converting enzyme inhibitors
Vasopressin
Radiographic contrast media
Non-steroidal anti-inflammatory drugs
opiates, codeine, amphetamine, polymyxin B, tubocurarine,
atropine, hydralazine, pentamidine, quinine and
radiocontrast media - may release mast-cell mediators
directly.
Cyclo-oxygenase inhibitors, such as aspirin and
indomethacin,
DRUGS CAUSING PHOTOSENSITIVITY.
Amiodarone
 Ampicillin
 Phenothiazines
 Antidepressants
 Chlorpromazine
Tetracyclines
 Griseofulvin
 Demeclocyclin
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LICHENOID ERUPTIONS
Drugs causing lichenoid eruptions.
 Antitubercular drugs
 Ethambutol
 Antimalarials
 Mepacrine (quinacrine, atebrin)
 Frusemide,
 diazoxide,
 tetracyclines,
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STEVENS-JOHNSON SYNDROME (S.J.S)
&
TOXIC EPIDERMAL NECROLYSIS (TEN)
MULTIPLE MUCOSAL LESION
SJS-TEN
SJS-TEN
STEVENS-JOHNSON SYNDROME (S.J.S)
&
TOXIC EPIDERMAL NECROLYSIS (TEN)
Anti-epileptic drugs (phenytoin, barbiturates,
carbamazepine and lamotrigine
 Ampicillin and other lactam antibiotics
 Sulphonamides (sulphadiazine, trimethoprimsulphamethoxazole, sulphadoxine),
 phenobarbital,
 chlormezanone
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DRUGS REPORTED TO EXACERBATE PSORIASIS
Antimalarials
 Lithium salts
 Non-steroidal anti-inflammatory drugs
 Buprofen
 Indomethacin
 Meclofenamate sodium
 Pyrazolon derivatives (phenylbutazone,
oxyphenbutazone)
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ACNE FORM ERUPTION
Lesions are papulopustular but comedones are
usually absent.
 Adrenocorticotrophic hormone (ACTH),
corticosteroids
 Dexamethasone in neurosurgical patients,
 Anabolic steroids for bodybuilding
 Isoniazid may induce acne
 Danazol
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FIXE DRUG ERUPTIONS
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Fixed eruptions characteristically recur in the same site or
sites each time the drug is administered
Cross-sensitivity to related drugs may occur, such as
between phenylbutazone and oxyphenbutazone and
between tetracycline type drugs.
Acute lesions usually develop 30 min to 8h after drug
administration
sharply marginated, round or oval itchy plaques of erythema
and oedema becoming dusky violaceous or brown, and
sometimes vesicular or bullous
Lesions are solitary at first, but with repeated attacks new
lesions usually appear and existing lesions may increase in
size.
Bullous fixed drug eruption
Co-trimoxazole (trimethoprim-sulphamethoxazole),
Tetracycline
Ampicilline
FDE GENITEL LESION
FDE
Hair changes
 Drug-induced alopecia
 Drug-induced hypertrichosis
 Drug-induced hair discoloration
 Nail changes
 Onycholysis
 Oral conditions
 Xerostomia
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THE MANAGEMENT OF DRUG REACTIONS
Diagnosis
 Drug history
 Drug elimination
 Skin testing
 Patch testing
 In vitro tests
 Tests for IgE antibody - RAST
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 Challenge
tests
 Treatment
Anaphylaxis
 Exfoliative dermatitis/erythroderma
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