Saturday, February 17, 2018

Melphalan-Drug for chemotherapy of neoplastic diseases


                                                                                                                                                                                                                                   MELPHALAN

MECHANISM OF ACTION –
 Alkylating agents work by three different mechanism :
1) Attachment of alkyl groups to DNA bases , forming monoadducts and resulting in the DNA being fragmented by repair enzymes in their attempts to replace the alkylated bases, preventing DNA synthesis and RNA transcription from the effected DNA
2) DNA damage via the formation of cross-links( bonds between atoms in the DNA ) which prevents DNA from being separated for synthesis or transcription
3) The induction of mispairing of the nucleotides leading to mutations.

PHARMACOLOGICAL ACTION –
Melphalan is an antineoplastic in the class of alkylating agents.
They stop tumor growth by cross linking guanine bases in DNA double helix strands – directly attacking DNA. This makes the strands unable to uncoil and separate .
In addition, these drugs add methyl or other alkyl groups onto molecules where they do not belong which in turn inhibits their correct utilization by base pairing and causes a miscoding of DNA.
They causes disruption of DNA function and cell death.

USES –
1. It is used to treat various forms of cancer.
2. Effective in multiple myeloma.
3. Used in ovarian cancer.

SIDE EFFECTS –
Black, tarry stools
Blood in urine or tools
Cough or hoarseness, accompanied by fever or chills
Fast or irregular beats
Fever or chills
Shortness of breath
Skin rashes or itching
Troubled bleeding
Unusual bleeding or bruising


DRUG-DRUG INTERACTION –
Melphalan + Clozapine = risk or severity of adverse effect can be increased.
Melphalan + Cyclosporine = may increase the nephrotoxic activities of Cyclosporine.
Melphalan + Metimazole = risk or severity of adverse effect can be increased.

Reference- Tripathi KD," Essentials of Medical Pharmacology",7th edition, page no-858,860

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