21. Chemotherapy of Neoplasia I

Question 1

A 44 year old patient has been diagnosed with cancer . They are prescribed Methotrexate but after administration it is found to be ineffective because it is found the patient lacks the enzyme to convert the medication to its active state. What is the enzyme the patient lacks?

A. HGPRT 
B. FPGS 
C. DHF reductase
D. Topoisomerase II
E. Xanthine Oxidase

RFA

Answer 1

Ans. B. Methotrexate undergoes a conversion to to a series of polyglutamates (MTX-PGs) by Folylpolyglutamate synthase(FPGS)

A. HFPRT-is need to activate 6-MP not Methotrexate

C. DHF-reductase- this is the enzyme that Methotrexate inhibits

D. Topoisomerase II-is inhibited by Etoposide

D. Xanthine Oxidase- metabolizes 6-MP and should be treated with Allopurinol to avoid hyperuricemia.

Question 2

A 72 year old women is under going chemotherapy and the doctor is concerned about neutropenia. Which medication should the patient to help treat this condition?

A. Filgrastim
B.  NK-inhibitor 
C. Dexrazoxane
D. Mesna
E. Amifostine 

RFA

Answer 2

Ans. A. Filgrastim- is used in prevention of neutropenia, Sargramostim also is used for this reason

B. NK-1 inhibitors- used to manage chemotherapy induce emesis, 5HT3 receptor blockers can also be given

C. Dexrazoxane- reduces anthracycline- induce cardiotoxicity

D. Mesna- reduces hemorrhagic cystitis caused by cyclophosphamide

E. Amifostine- reduces renal toxicity caused by cisplatin