TMPT

Question 1

What is the use of 6-mercaptopurine?

Answer 1

Used as chemotherapy

Used to treat some forms of leukemia

Question 2

What is the mechanism of action of 6-mercaptopurine?

Answer 2

Functions by inhibition of the purine biosynthetic pathway which are needed for the formation of nucleotides, and thus production DNA + RNA

• in this way, 6-mercaptopurine slows proliferation
• cancer growth is inhibited as nucleotides are needed for cellular proliferation

Question 3

Explain thiopurine S-methyltransferase polymorphism

Answer 3

• most alleles encode fir functional enzyme
• a few Dont , these variants may be thought of as deficiency alleles
• Approximately 1/300 individuals are homozygous for genetic variants that lead to low TPMT activity
• They are at increased risk for life threatening myelosuppression when treated with standards doses of thiopurine drugs
  
  • For these patients, a standard dose is, in effect, an overdose
  • If 6-mercaptopurine is given, dose must be reduced