Hem Onc Drugs Flashcards
unfractionated heparin mechanism
- activates antithrombin
- inhibition of IIa (thrombin), Xa –> larger polysaccharides
- shorter half life
low MW heparin mechanism
- activates antithrombin
- inhibition of Xa»_space; IIa (thrombin) –> smaller polysaccharides
- longer half life
fondaparinux mechanism
- activates antithrombin
- inhibits Xa –> synthetic
- longer half life
SEs of heparin
- bleeding
- heparin induced thrombocytopenia (HIT)
- osteoporosis
heparin antidote
protamine (cationic molecule that binds up anionic heparin)
clinical use of heparin
- PE
- ACS - unstable angina, AMI
- DVT
- does not cross placenta, so good for pregnancy
labs to follow for heparin
PTT
warfarin mechanism
- interferes with gamma-carboxylation of vit K dependent factors II, VII, IX, X and proteins C and S
- vit K “antagonist”
labs to monitor for warfarin
PT INR (should be 2-3)
clinical use of warfarin
- prophylaxis for venous thromboembolism
- prevent stroke in a fib, a flutter
SEs of warfarin
- fetal warfarin syndrome - hypoplastic nose and limbs, flat face, altered calcification
- warfarin skin necrosis - since protein C and S have shorter half-lives than the coagulation factors, there will be a state of initial hypercoagulability leading to thromboses in breast, buttocks, penis, extremities (most common in F who receive huge loading doses)
antidote for warfarin
vitamin K, fresh frozen plasma if it is urgent
heparin bridging
- heparin given when starting warfarin for anticoagulation during initial hypercoagulable state caused by lack of protein C and S before lack of coagulation factors
- to prevent warfarin skin necrosis
bivalirudin
direct thrombin (IIa) inh
argatroban
direct thrombin (IIa) inh
dabigatran
direct thrombin (IIa) inh
-aban drugs
direct Xa inh
mechanism of aspirin
- irreversible inhibition of COX1 and COX2 by covalent acetylation
- leading to impaired TXA2 production from arachidonic acid for the entire life of the platelet (platelets cannot synthesize more enzyme)
mechanism of clopidogrel, prasugrel
irreversible inhibitor of platelet adenosine (ADP) receptor to prevent platelet aggregation
mechanism of -grelor drugs
reversible inhibitor of platelet adenosine (ADP) receptor to prevent platelet aggregation
GPIIb/IIIa inhibitors include:
abciximab
eptifibatide
tirofiban
mechanism of -plase drugs/streptokinase
- aid conversion of plasminogen to plasmin, which cleaves thrombin and fibrin clots
Clinical use of direct thrombin inhibitors (argatroban, bivalirudin, dabigatran)
- alternatives to UFH for anticoagulation
- used in the case of heparin-induced thrombocytopenia
mechanism of -aban drugs
inhibit Xa
clinical use of -aban drugs
- treatment and prophylaxis for DVT, PE
- stroke prophylaxis for a. fib.
clinical use of -plase drugs/streptokinase
- early MI
- early ischemic stroke
- severe acute PE
How to treat -plase drug/streptokinase overdose?
- aminocaproic acid inhibits fibrinolysis
- fresh frozen plasma and cryoprecipitate to correct factor deficiencies
clinical use of aspirin
- antipyretic
- analgesic
- anti-inflammatory
- anti-platelet
SEs of aspirin
- gastric ulceration, tinnitus
- chronic: renal failure, interstitial nephritis, upper GI bleeding
- Reye’s syndrome in kids with viral infxns
- mixed respiratory alkalosis/metabolic acidosis
clinical use of ADP receptor inhibitors
- acute coronary syndrome, coronary stenting
- decrease of recurrence of thrombotic stroke
SEs of ADP receptor inhibitors
neutropenia, TTP
mechanism of cilostazol, dipyridamole
PDE3 inhibitors raise cAMP in platelets, resulting in inhibition of platelet aggregation and vasodilation
clinical uses of cilostazol, dipyridamole
- intermittent claudication
- prophylaxis for strokes, TIAs, angina
- for coronary dilation
clinical use of GP IIb/IIIa inhibitors (abciximab, eptifibatide, tirofiban)
- unstable angina
- percutaneous transluminal coronary angioplasty
mechanism of cyclophosphamide, ifosfamide
- alkylating agents
- strongly cationic drug cross-links negatively charged DNA
- requires bioactivation by CYP450 in liver
SEs of cyclophosphamide, ifosfamide
- myelosuppression
- immunosuppresion
- hemorrhagic cystitis - acrolein, a byproduct of metabolism, is toxic (treated with mesna which binds up acrolein covalently)
mechanism of 6-mercaptopurine, 6-thioguanine
- require lethal synthesis into 5’ phosphate ribonucleotide (activation by HGPRT)
- pseudo-feedback to decrease body’s normal purine synthesis (so much of a molecule that is structurally similar, body screws up and recognizes it as endogenous and doesn’t make more)
- incorporated into DNA»_space; RNA
SEs of 6-MP, 6-TG
- myelosuppression, GI and liver toxicity
- 6-MP metabolized by xanthine oxidase, so don’t give this drug with allopurinol for gout
mechanism of 5-fluorouracil (5-FU)
- requires lethal synthesis into 5’ phosphate ribonucleotide
- covalently complexes folic acid, and this complex inhibits thymidylate synthase –> inhibits pyrimidine synthesis
- incorporates into RNA»_space; DNA
SEs of 5-FU
myelosuppression
mechanism of cytarabine
pyrimidine analogue –> inhibits DNA pol
SEs of cytarabine
leukopenia, thrombocytopenia ,megaloblastic anemia
mechanism of doxorubicin, daunorubicin, anthracyclin
intercalates DNA causing expansion and warping –> DNA breaks
SEs of doxorubicin, daunorubicin, anthracyclin
- dilated cardiomyopathy (dexrazoxane can prevent cardiotoxicity)
- myelosuppression
- alopecia
mechanism of bleomycin
binds to DNA to cause ss, ds DNA breaks
SEs of bleomycin
- pulmonary fibrosis
- skin hyperpigmentation
- mucositis
- mild myelosuppression
mechansim of dactinomycin
intercalates DNA
mechanism of -platin drugs
electrophilic molecules that cross-link DNA
clinical use of -platin drugs
testicular, bladder, ovary, lung carcinomas
SEs of -platin drugs
- nephrotoxicity (prevent with amifostine and saline diuresis)
- ototoxicity
mechanism of vincristine, vinblastine
vinca alkaloids that bind B-tubulin and inhibit its polymerization into microtubules, preventing mitotic spindle formation (M phase arrest –> apoptosis)
SEs of vincristine, vinblastine
neurotoxicity, paralytic ileus
mechanism paclitaxel
prevents mitotic spindle breakdown, prevents depolymerization of tubulin after M phase
clinical use of paclitaxel
ovarian, breast carcinomas
SEs of paclitaxel
- myelosuppression
- alopecia
- stocking/glove neuropathy
mechanism of -poside drugs
inhibition of topoisomerase II –> dsDNA breaks
SEs of -poside drugs
myelosuppression, GI upset, alopecia
mechanism of -tecan drugs
inhibition of topoisomerase I –> ssDNA breaks
prevents unwinding/replication
toxicity of -tecan drugs
- myelosuppression
- diarrhea
mechanism of hydroxyurea
inhibits ribonucleotide reductase - decrease in DNA synthesis (S phase specific)
SEs of hydroxyurea
- myelosuppression
- GI upset
- birth defects
- skin hyperpigmentation
mechanism of prednisone
anti-inflammatory glucocorticoid that alters gene transcription, suppresses lymphocytes
SEs of prednisone
Cushings symptoms - weight gain, central obesity, muscle breakdown, cataracts, acne, osteoporosis, HTN, peptic ulcers, hyperglycemia, psychosis, immunosuppression, pancreatitis
mechanism of bevacizumab
monoclonal antibody against VEGF - inhibits angiogenesis
SEs of bevacizumab
hemorrhage, blood clots, impaired wound healing, flu-like symptoms
mechanism of imatinib
tyrosine kinase inhibitor of BCR-ABL (Philly chromosome fusing gene in CML) and c-kit (gI stromal tumors)
clinical use of imatinib
- CML with 9:22 translocation
- GI stromal tumors
SEs of imatinib
fluid retention, fever, nausea
mechanism of rituximab
monoclonal ab. against CD20
SEs of rituximab
- progressive multifocal leukoencephalopathy
- activation of latent infections - run TB, HIV, hep tests before starting
mechanism of tamoxifen
selective estrogen receptor modulator - ER antagonist in breast
clinical use of tamoxifen
ER+ breast cancer
SEs of tamoxifen
- endometrial cancer
- hot flashes, mood swings
- risk of thromboembolism
mechanism of bortezomib
reversible proteasome inhibitor - accumulation of unwanted proteins in cells –> apoptosis
mechanism of trastuzumab
monocloncal antibody against HER-2, a tyrosine kinase receptor
clinical use of trastuzumab
HER-2+ breast cancer and gastric cancer
SEs of trastuzumab
cardiotoxicity
GnRH agonists include:
leuprolide, histerelin, nafarelin
mechanism of GnRH agonists
flare of testosterone production such that feedback prevents further production (chemical castration)
clinical use of GnRH agonists
prostate cancer
GnRH antagonists include:
abarelix, triptorelin
mechanism of GnRH antagonists
no pituitary stimulation, so ultimately underproduction of testosterone
clinical use of GnRH antagonists
prostate cancer
mechanism of anastrozole
aromatase inhibitor, so less estrogen/testosterone production
clinical use of anastrozole
ER+, PR+ breast cancer
SEs of anastrozole
thromboembolism, osteoporosis