University:
University of North Carolina at Chapel Hill
Course:
NURS 312 | Pharmacology
Academic year:

2020
Views:

259

Pages:

1
Author:

Prince Sampson

2.4 – “Untangled “Untangled”: ”: Topo Topoisomerase isomerase inhibitor inhibitorss • Topoisomerase enzymes relieve the tension in DNA supercoils by nicking and re-ligating the DNA. Topoisomerase I nicks ssDNA and is involved in the process of DNA unwinding during replication, while topoisomerase II breaks and re-ligates dsDNA breaks. The topoisomerase inhibitors interfere with one of these steps and are used in cancer treatment (crab flag). • Inhibitors all specific to S-phase of the cell cycle, preventing movement to G2 (Rapunzel cannot descend the Stairs because they are broken and the witch is Gone 2 the forest). • Etoposide & teniposide o inhibit topoisomerase II →↑DNA degradation. (Rapunzel is climbing down the side of the tower on two-strand twists; but both strands have broken!) o Used in treatment of solid tumors, particular testicular and small cell lung cancer, as well as leukemias & lymphomas. o Toxicities: ▪ Myelosuppression and consequent immunosuppression (empty bone-shaped luggage. Witch with immunocompromised cane) ▪ Alopecia (Rapunzel is losing a lot of hair) • Topotecan and irinotecan o topoisomerase I inhibitors (man’s toucan sounds like -tecan. Man has a single-stranded ponytail rather than a double-stranded twist). o Used to treat ovarian and small cell lung cancers; irinotecan is used in colon cancer. o Toxicities ▪ Myelosuppression ▪ Severe and profuse diarrhea, some days after initiating treatment, d/t cell toxicity in GI tract (bird pooping). Can be so severe as to cause volume depletion.