Adverse Drug Reactions 49induced hemolytic anaemia, sulfonamide-
induced granulocytopenia and quinidine-
induced cytopenic purpura.
TYPE-III (ARTHUS REACTION IGG
MEDIATED)
These reactions are predominantly me-
diated by IgG. The antigen-antibody com-
plexes are deposited in the vascular endot-
helium, where a destructive inflammatory
response occurs. Serum sickness, clinical
symptoms include fever, skin eruptions, ar-
thralgia and lymphadenopathy. The reac-
tion usually subsides in 6-12 days.
The drugs inducing serum sickness are
sulfonamides, penicillin etc. Sulfonamides
also cause Stevens-Johnson syndrome, a form
of immune vasculitis, which is characterized
by the reactions including arthritis, nephritis,
myocarditis and certain mental symptoms.
TYPE-IV (DELAYED
HYPERSENSITIVITY)
These reactions are mediated by
production of sensitized T-lymphocytes. On
contact with antigen, an inflammatory
reaction is generated which includes contact
dermatitis, fever and photosensitization.
Drugs which cause these types of
reactions are penicillin, sulfonamides,
tetracycline, phenylbutazone, salicylates etc.
TERATOGENICITYTeratogenicity is derived from the word ‘teratos’
mean ‘monster.’ Teratogens may act directly on
the foetus, e.g., thalidomide and anticancer drugs
act directly on the foetus, or act indirectly on
placenta e.g., vitamin A, 5-HT.
It is clear that the major foetal damage
occur by drug when it is taken in early
pregnancy (i.e. first 2-9 weeks when
organogenesis takes place.)
The teratogenic drugs can affect
different stages of pregnancy i.e.- At fertilization and implantation stage
(i.e. conception to 3 weeks). - Organogenesis period (3 to 9 weeks),
and - In growth and development period
(i.e., after 9 weeks).
The drugs, which are proven to be
teratogenic are thalidomide, anticancer
drugs (specially methotrexate), sex
hormones (androgens, progestins,
stilboesterol) corticosteroids, warfarin,
antithyroid drugs (which can cause foetal
goitre and hypothyroidism), oral antidia-
betic drugs, and social drugs including
tobacco, alcohol etc.
CARCINOGENICITY
Certain drugs affect the genes and structural
changes in the chromosomes. The drugs that
cause cancer are called as carcinogenic
drugs, for example, oral contraceptives in-
crease the incidence of benign liver tumors,
vaginal adenocarcinoma in the female off-
springs of women who have taken
stilboesterol during her pregnancy for abor-
tion purpose.
Drugs producing carcinogenic effects are
anticancer/antineoplastic drugs, radioisotopes
like P^32 , I^131 and hormonal therapy etc.