Chemo IV Antimetabolites Flashcards

1
Q

Methotrexate- Mech of Action

A

POLYGLUTINATED AND RETAINED WITHIN CANCER CELLS
INHIBIT DIHYDROFOLATE REDUCTASE= PREVENT PURINE SYNTHESIS

target= dihydrofolate reducase

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2
Q

Methotrexate- Cell Cycle Specificity

A

S PHASE

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3
Q

Methotrexate- Kinetics

A

PROTEIN BOUND- ADMINISTRATION WITH OTHER DRUGS MAY POTENTIATE TOXICITY

DISTRIBUTES THROUGH TOTAL BODY WATER- CONTRAINDICATED IN ASCITES AND PLEURAL EFFUSION

EXCRETED BY KIDNEY- CAUTION IN KIDNEY DISEASE

EXCRETED AS A SALT OF A WEAK ACID- OTHER DRUGS ALSO EXCRETED THIS WAY MAY PREENT EXCRETION- ASPIRIN, PENICILLINS

HIGH DOSES CROSS BBB
MORE SOLUBLE IN ALKALINE, THUS ALKALINIZE URINE TO PROMOTE EXCRETION–>ADD SODIUM BICARB

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4
Q

Methotrexate- Clinical Use

A

INTRATHECAL ADMINISTRATION FOR CARCINOMATOUS OR LLYMPHOMATOUS MENINGITIS

breast cancer
leukemia
lymphoma
rheumatoid arthritis
psoriasis
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5
Q

Methotrexate- Toxicities

A

MYELOSUPPRESSION- LIMITING
mild nausea and vomiting, stomatitis

can rescue bone marrow and intestinal epithelial cells from drug effects via administration of Leucovorin (tetrahydrofolate)- these cells have less polyglutinated drug than the cancer cells

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6
Q

Premetrexed- Mech of Action

A

Anti-folate- inhibits thymidine syntahse

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7
Q

Premetrexed- Cell Cycle Specificity

A

S PHASE

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8
Q

Premetrexed- Clinical Use

A

lung cancer

mesothelioma

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9
Q

Premetrexed- Toxicities

A

Myelosuppresion- limiting

rash
stomatitis
diarrhea
hand-foot syndrome

pretreatment w/ B-12 and oral folic acid decreases the amount of myelosuppression

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10
Q

Cytarabine (cytosine arabinoside), Gemcitabine- Mech of Action

A

active form is triphosphate form activated by kinases

INHIBITS DNA POLYMERASE BY INCORPORATING INTO DNA AND INHIBITING TEMPLATE FUNCTION AND CHAIN ELONGATION

target= DNA

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11
Q

Cytarabine (cytosine arabinoside), Gemcitabine- Cell Cycle Specificity

A

S PHASE

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12
Q

Cytarabine (cytosine arabinoside)- Kinetics

A

Short half life- coupled with cell cycle specificity means the drug has SCHEDULE DEPENDENT CYTOTOXICITY

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13
Q

Cytarabine (cytosine arabinoside)- Clinical Use

A

ACUTE LEUKEMIA

intrathecal administration for carcinomatous or lymphomatous meningitis

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14
Q

Gemcitabine- Kinetics

A

not schedule dependence

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15
Q

Gemcitabine- Clinical Use

A

PALLIATIVE TREATMENT OF PANCREAS AND LUNG CANCER

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16
Q

Cytarabine (cytosine arabinoside), Gemcitabine- Toxicities

A

MYELOSUPPRESSION- LIMITING

HIGH DOSE CAN CAUSE CEREBELLAR TOXICITY AND CONJUNCTIVITIS

hepatic toxicity
nausea
vomiting
hair loss 
stomatitis
17
Q

5-Fluorouracil- Mech of Action

A

phosphorylated to triphosphate form and converted to fdUMP

FDUMP INHIBITS THYMIDYLATE SYNTHETASE AND DECREASES PRODUCTION OF THYMINE, ALSO INCORPORATES INTO DNA AND RNA

target= thymidylate synthetase, DNA, RNA

18
Q

5-Fluorouracil- Cell Cycle Specificity

A

S PHASE

19
Q

5-Fluorouracil- Kinetics

A

OFTEN GIVEN WITH RADIATION AS A RADIATION SENSITIZER

LEUCOVORIN POTENTIATES EFFECTS OF 5-FU, MORE EFFECTIVE BUT ALSO MORE SIDE EFFECTS

20
Q

5-Fluorouracil- Clinical Use

A

Breast cancer
head and neck cancer
GI cancers

21
Q

5-Fluorouracil- Toxcities

A
RASH
STOMATITIS
DIARRHEA
MILD MYELOSUPPRESSION
HYPERPIGMENTION (SUN SENSITIVITY)
chest pain (coronary artery vasospasm)
cerebellar ataxia
excess alcrimation
hand-foot syndrome
22
Q

Capecitabine- Mech of Action

A

produrg of 5-FU

cleaved to active form by enzyme mostly expressed in cancer cells

23
Q

Capecitabine- Cell Cycle Specificity

A

S PHASE

24
Q

Capecitabine- Kinetics

A

oral replacement for 5-FU

25
Q

Capecitabine- Clinical Use

A

GI malignancies

breast cancer

26
Q

Capecitabine- Toxicities

A

rash
hand-foot syndrome
diarrhea
myelosuppression

27
Q

6-Mercaptopurine- Mech of Action

A

metabolized to 6-thioinosinic acid

6-THIOINOSINIC ACID INHIBITS ENZYMES OF DE NOVO PURINE SYNTHESIS

target= RNA and DNA

28
Q

6-Mercaptopurine- Kinetics

A

degraded by xantine oxidase

REDUCE DOSE IF GIVEN WITH ALLOPURINOL (A XANTHINE OXIDASE INHIBITOR)

29
Q

6-Thioguanine- Kinetics

A

not degraded by xanthine oxidase

no dose reduction with allpurinol

30
Q

6-Mercaptopurine, 6-Thioguanine- Cell Cycle Specificity

A

S Phase

31
Q

6-Mercaptopurine, 6-Thioguanine- Clinical Use

A

CHILDHOOD ACUTE LEUKEMIA

32
Q

6-Mercaptopurine, 6-Thioguanine- Toxicities

A

MYELOSUPPRESSION- LIMITING