Pharmacology for Dentistry

376 Section 9/ Chemotherapy

testicular tumour, squamous cell carcinoma
of skin, neck and head, genitourinary tract
and oesophagus neoplasm, malignancy of
cervix, Hodgkin’s and non Hodgkin’s lym-
phoma, choriocarcinoma and embryonal
cell carcinoma of testis, brain tumour and
glioma.

MITOMYCIN-C

It is a highly toxic antibiotic with
antitumour activity isolated from
Streptomyces caespitosus.

It inhibits DNA synthesis and cross
links DNA.

After oral administration it exhibits
inconsistent absorption. Hence it is
administered by IV route and is metabolised
in liver.

It is used in the treatment of adenocar-
cinoma, lymphosarcoma and seminoma. It
is also used in squamous cell carcinoma of
cervix.

Adverse effects include nausea,
vomiting, alopecia, pulmonary fibrosis,
bone marrow depression, sterility,
amenorrhoea and renal toxicity.

VINCA ALKALOIDS

The vinca alkaloids are isolated from plant
Vinca rosea. They are cell cycle specific and
mitotic inhibitors.

VINCRISTINE

It blocks mitosis and produces
metaphase arrest by binding to microtu-
bular protein ‘tubulin’, preventing its
polymerization.

After oral administration the absorp-

tion is unpredictable. It is metabolised in

liver.

Adverse effects include local reaction

if extravasation occurs, constipation, para-

lytic ileus, jaw pain, alopecia, bone mar-

row depression, peripheral neuropathy,

inappropriate ADH secretion, shortness of

breath and bronchospasm.

It is indicated in acute leukaemias, lym-

phomas, Ewing’s sarcoma, neuroblastoma,

Wilm’s tumour and idiopathic thrombocy-

topenic purpura.

VINBLASTINE

It interferes with metabolic pathways

of amino acids leading from glutamic acid

to the citric acid (Krebs) cycle and urea.

Vinblastine has an effect on cell energy

production required for mitosis and

interferes with nucleic acid synthesis.

Reversal of antitumour effect by glutamic

acid or tryptophan has occurred.

It undergoes rapid distribution and

extensive tissue binding following IV

injection. It is metabolised in liver.

Adverse effects include hepatic

function impairment, leucopenia,

aspermia, nausea, vomiting, hypertension

and alopecia.

It is indicated in Hodgkin’s and non

Hodgkin’s lymphoma, testicular

carcinoma, mycosis fungoides and Kaposi’s

sarcoma.

VINORELBINE

It is semisynthetic vinca alkaloid. It

interferes with microtubules, in miotic

spindle fibres leading to cell cycle arrest