378 Section 9/ Chemotherapyogy is discussed in chapter ‘Oral Contra-
ceptives.’
MEGESTROL ACETATE
It belongs to group of progesterone
which are mainly used as second or third
line therapy in breast and endometrial
cancer.
Adverse effects include nausea, acne,
fluid retention, GI disturbances and weight
changes.
TAMOXIFEN
It exerts its action by binding to
estrogen receptors. Tumours with estrogen
receptors respond.
It is given orally, the drug has biphasic
half life and is primarily excreted in bile.
Adverse effects include nausea,
vomiting, hot flushes, vaginal bleeding,
pruritus vulvae and menstrual
irregularities.
It is used as palliative treatment of
estrogen receptor positive advanced or
metastatic carcinoma of breast.
MISCELLANEOUS AGENTSHYDROXYUREA
The primary action is inhibition of
enzyme ribonucleoside diphosphate
reductase. The drug is specific for S phase
of the cell cycle and causes cell to arrest
at the G 1 -S interface.
After oral administration it is readily
absorbed from GI tract. Hydroxyurea
readily crosses blood brain barrier.
It is indicated in treatment of chronic
granulocytic leukaemia, polycythemia
vera, essential thrombocytosis, melanoma,
metastatic or inoperable carcinoma of
ovary. In combination with radiotherapy
in carcinoma of cervix, head, neck and
lung.
Adverse effects include nausea, vom-
iting, rash. Bone marrow depression is the
major toxic effect. Alopecia, stomatitis,
dysuria; inflammation and increased pig-
mentation may occur in areas exposed to
radiation. Rarely neurological distur-
bances occur.PROCARBAZINE
After metabolic activation, it depoly-
merizes DNA and causes chromosomal
damage and also nucleic acid synthesis
inhibition. It is found to be effective in
Hodgkin’s disease and carcinoma of
lungs.
Adverse effects include drowsiness,
restlessness, anaemia, leucopenia, throm-
bocytopenia, bone marrow toxicity and
disulfiram like reaction with alcohol.L-ASPARAGINASE
It destroys essential amino acid
(asparagine) hence leukaemic cells are
deprived of amino acid and leads to cell
death. It is given by parenteral route.
Adverse effects include nausea, vom-
iting, headache, fever, abdominal pain,
hyperglycemia leading to coma, hypersen-
sitivity, renal damage, coagulation defects,
thrombosis, CNS depression or hyperex-
citability and acute haemorrhagic pancre-
atitis.
It is used in the treatment of malignant
lymphoma and acute leukaemia.