Pyrimidine Antagonist Flashcards

Question

What drug(s) notably require monitoring of INR if on concomitant warfarin therapy?

Answer 1

Drug(s) notably requiring this monitoring are: - 5Fluorouracil - Capecitabine

Answer 2

The emetic potential of this drug is: - Low

Answer 3

The emetic potential of this drug is: - Low

Answer 4

The emetic potential of this drug is: - Low

Answer 5

The emetic potential of this drug is: - Adults: - Moderate if >1,000 mg/m2 - Low if ≤1,000 mg/m2 - Pediatrics: - High if ≥3,000 mg/m2/day: High (>90%). - Moderate for 75 mg/m2/dose.

Answer 6

The emetic potential of this drug class is: - Low (except for Cytarabine*)

Answer 7

The extravasation risk and management strategies for this drug class are as follows: - Fluorouracil may be an irritant. avoid extravasation.

Answer 8

The administration of this drug is described as follows: - 5-FU is given as a 46-hour continuous infusion with some chemotherapy regimens. - In these cases, leucovorin is often given to enhance the mechanism of 5-FU by adding additional inhibition of thymidylate synthase. This leads to increased cancer cell death but can also cause increased toxicities.

Answer 9

The administration of this drug is described as follows: - It is given orally often in divided doses, 12 hours apart, for 2 weeks on and 1 week off. - It should be taken with food. - Oral administration is similar to continuous infusion 5-FU in terms of toxicity.

Answer 10

The administration of this drug is described as follows: - Administered as a continuous hepatic intra-arterial infusion using an infusion pump.

Answer 11

The metabolism of this drug is as follows: - HEPATICALLY metabolized to form active metabolites. 5-fluoroxyuridine monophosphate (F-UMP) and 5-5-fluoro- 2'-deoxyuridine-5'-0 -monophosphate (F-dUMP)

Answer 12

The metabolism of this drug is as follows: - Enzymatically metabolized to fluorouracil.

Answer 13

The metabolism of this drug is as follows: - Metabolized intracellularly by nucleoside kinases to the active diphosphate (dFdCDP) and triphosphate (dFdCTP) nucleoside metabolites

Answer 14

The metabolism of this drug is as follows: - Primarily hepatic - Metabolized by deoxycytidine kinase to aracytidine triphosphate (active) - ~90% of dose is metabolized to inactive uracil arabinoside (ARA-U); intrathecal administration results in little conversion to ARA-U due to the low levels of deaminase in the cerebral spinal fluid.

Answer 15

The notable ADRs of this drug are: - Hand-foot syndrome, also called palmar-plantar erythrodysesthesia. Patients can experience redness, swelling, and pain on the palms of the hands and/or the soles of the feet. - A bolus dose of 5-FU is associated with myelosuppression while the continuous infusion 5-FU/capecitabine is more likely to cause diarrhea and hand/foot syndrome.

Answer 16

The notable ADRs of this drug are: - Hand-foot syndrome, also called palmar-plantar erythrodysesthesia. Patients can experience redness, swelling, and pain on the palms of the hands and/or the soles of the feet.

Answer 17

The notable ADRs of this drug are: - Cytarabine syndrome which is almost flu-like and is characterized by fever, myalgia, bone pain, chest pain (occasionally), maculopapular rash, conjunctivitis, and malaise. - Occurs in up to 1/3rd of patients receiving Cytarabine for AML (most of whom have had prior exposure to the drug) - It generally occurs 6 to 12 hours following administration.

Answer 18

The notable/common ADRs of this drug class are: - Hand/Foot Syndrome (especially 5Fluorouracil and Capecitabine)

Answer 19

The drugs in this class notable for cause this condition are: - 5Fluorouracil and Capecitabine (and to a lesser degree Cytarabine)

Answer 20

The strategy and rationale for management of this condition caused by this drug are: - Leucovorin is often given to enhance the mechanisam of 5-FU by adding additional inhibition of thymidylate synthase. This leads to increased cancer cell death but can also cause increased toxicities. - In patients who are poorly tolerating their 5-FU/leucovorin containing regimens. you may consider omitting the leucovorin (instead of decreasing the 5-FU dose)

Answer 21

The strategy and rationale for management of this condition caused by this drug are: - It is thought to be caused by damage to the deep capillaries, leading to COX inflammatory-type reactions or related to enzymes involved in 5-FU metabolism - It can be prevented by avoiding friction causing activities (lifting weights, running), avoiding hot water or other sources of heat, and using lotions or creams to keep skin moist. - It is treated by holding chemotherapy, and applying topical or oral anti-inflammatory agents and analgesics.

Answer 22

The strategy and rationale for management of this condition caused by this drug are: - While the etiology is unclear, it is probably related to cytokine release rather than immune-mediated - Acetaminophen before and after dose may reduce the frequency of the cytarabine syndrome. - Glucocorticoids may also be beneficial for both treatment and prevention of the cytarabine syndrome. - Retreatment after Cytarabine syndrome can usually be safely accomplished with increased premedication, even in patients with multiple reactions

Answer 23

The clinical pearls of this drug are as follows: - Oral capecitabine has many drug interactions to be aware of including: - PPIs (which can decrease efficacy) - Warfarin (increased INR)