Heme/Onc Flashcards
Heparin
MOA: cofactor for the activation of antithrombin, decreased thrombin and decreased factor Xa
Clinical: immediate anticoagulant for PE, acute coronary syndrome, MI, DVT-prophylaxis in knee and hip surgery and non ambulatory patients
Used during pregnancy
Follow PTT
Toxicity: bleeding, thrombocytopenia (IgG antibodies againts heparin boud to platelet factor 4) , osteoporosis, drug-drug interactions
Protamine sulfate for antidote (postively charged binds negatively charged heparin-not effective for LMWH)
enoxaprin
LMWH
active antithrombiin III
Act more on factor Xa
Longer half life and better bioavailability
Administered subcutanoeusly and without lab monitoring
Significantly reduces death and recurrent MI when used acutely for MI
better for acute coronary syndrome
Argatroban, bivalirudin, lepirudin
Derivatives hirudin an anticoagulant used by leeches
Inhibit thrombin directly (do not require antithormbin III)
Used in patients with heparin induced thrombocytopenia
Warfarin
MOA: interfers with normal synthesis and y-carboxylation of glutamic acid of Vitamin K (clotting factors II, VII, IX and X, proteins C and S)
Metabolized by cytochrome P-450 pathway
Monitor PT/ INR
Clinical: chronic anticoagulation (after STEMI, venous thromboembolism prophylaxis, and prevention of stroke in A. fib)
Not used in pregnant women
Toxicity: bleeding, teratogenic (fetal hemorrhagic jaundice, optic neuritis), skin/tissue necrosis, drug-drug interactions
Warfarin overdose: vitamin K antidote
Rapid reversal: fresh frozen plasma
Aixaban, rivaroxaban
MOA: direct Xa inhibitors
Clinical: treatment and prophylaxis of DVT and PE (Riva), stroke propylaxis in patients with A. fib
Toxicity: bleeding
Altepase, reteplase, tenectelplase
Thrombolytics-alteplase (tPA), reteplase (rPA), tenecteplase (TNK-tPA)
MOA: diretly or indirectly aid conversion of plasminogen to plasmin which cleaves thrombin and fibrin cltos
Increases PT, PTT with no change in platelet count
Clinical: early MI (within 6 hours) early ischemic stroke, direct thrombolysis of severe PE, acute ST eleveation MI decreases mortality
Toxicity: Bleeding, restoration of blood flow after clot lysis can lead to benign arrhythmias
CI: patients with active bleeding, history of intracranial bleeding, recent surgery, known bleeding diatheses, or severe hypertension
Treat toxicity with aminocarpoic acid inhibitor of fibrinolysis
Fresh frozen plasma and cryoprecipitate can also correct factor deficiencies
Aspirin
Irreversibly inhibits Cyclooxgenase (COX-1 and COX-2) by covalent acetlyation
Platelets cannot synthesize new enzyme
Increases BT, decreases TXA2, prostaglandins
No effect on PT or PTT
Clinical: Antipyretic, analgesic, anti-inflammatory, antiplatelet (decreases aggregation)
Toxicity: gastric ulceration, tinnitus,
Chronic use can lead to acute renal failure, interstitial nephritis, and upper GI bleeding
Reye syndrome in children with viral infection
Overdose causes respiratory alkalosis then superimposed metabolic acidosis
Clopidogrel
ADP receptor inhibitors
MOA: inhibit platelet aggregation by irreversibly blocking ADP receptors
Inhibit fibrinogen binding by preventing glycoprotein IIb/IIIa from binding to fibrinogen
Clinical: Acute coronary syndrome, coronary stenting, decrease incidence or recurrence of thormbotic stroke
Toxicity: netuorpenia (ticlopidine-fever and mouth ulcers), TTP/HUS
Cilostazol
MOA: phsopdiesterase III inhibitor
Increase cAMP in platelets preventing platelet shape change and granule release
Inhibiting platelet aggregation
Vasodilates
Clinical: intermittent claudication, coronary vasodilation, prevention of stroke or TIAs (with aspirin), angina prophylaxis
Toxicity: nausea, headache, facial flushing, hypotension, abdominal pain
Abcimiximab
GP IIb/IIIa inhibitors
MOA: bind to glycoprotein receptor IIb/IIIa on activated platelets, preventing aggregation
Clinical: unstable angina, percutaneous transluminal coronary angioplasty
Toxicity: bleeding, thromobcytopenia
Radiation therapy
Initiates cell death by
1. DNA strand breakage
2. Formation of free radicals
Most pronounced in rapidly dividing cells
Side effects: damage to epithileal surfaces (bowel and skin)
Methotrexate
MOA: folic acid analog that inhibits dihydrofolate reductase (irreversible)
Decraeses dTMP leading to decreased DNA and decreased protein synthesis
S phase specific
Resultant Increase Dihydroflolate polyglutamate
Clinical: leukemias, lymphomas, choriocarcinoma, sarcomas
abortion, ectopic pregnancy, rheumatoid arthritis, psoriasis, IBD, hydatiform mole
Toxicity: myelosuppresion-reversible with leucorvin
leucorvin does not require DHF reductase to convert to THF
Macorvesicular fatty change in liver (Incrased ALT and AST)
Mucositis, stomatitis-painful ulcers
Teratogenic
B cell lymphoma, opportunistic infections
Pulmonary fibrosis
5-fluorouracil
MOA: pyrimidine analog bioactivated to 5F-dUMP which covalently complexes folic acid
Inhibits thymidylate synthase leading to decreased dTMP and decreased DNA protein and protein synthesis
Clinical: colon cancer, pancreatic cancer, basal cell carcinoma
Toxicity: myelosuppression, photosensitivity
Overdose rescue with uridine
Cytarabine
MOA: pyrimidine analog leading to inhibition of DNA polymerase
Clinical: leukemias, lymphomas
Toxicity: leukopenia, thrombocytopenia, megaloblastic anemia (panCYTOpenia)
Azathiprine, 6-mercaptopurine, 6-thioguanine
MOA: purine analogs decreasing de nova pruien synthesis
activated by HGPRT
Clinical: preventing organ rejection, Rheumatoid arthritis, SLE (Azothiroprine), leukemia and IBD (6-MP, 6-TG)
Toxicity: bone marrow, GI, liver
Axothioprine and 6-MP metabolized by xanthine oxidase which increases toxicity with allopurinol
Dactinomycin (actinomycin D)
MOA: intercalates in DNA
Clinical: wilms tumor, Ewing sarcoma, rhabdomyosarcoma
Childhood tumors
Toxicity: myelosuppression
Doxorubicin (Adriamycin), daunorubicin
MOA: generate free radicals
Intercalate in DNA leading to breaks in DNA decreasing replication
Clinical: solid tumors, leukemias, lymphomas
Toxicity: cardiotoxicity (dilated cardiomyopathy), myelosuppressin, alopecia
Toxic to tissues following extravasation
Dexrazoxane (iron chelator), prevents cardiotoxicity
Bleomycin
MOA: induces free radical formation which causes breaks in DNA strands
Clinical: testicular cancer, Hodgkin lymphoma
Toxicity: pulmonary fibrosis, skin changes, mucositis, minimal myelosuppression
Cyclophosphamide, ifosfamide
MOA: covalently X link DNA at guanine N-7
Require activation by liver
Clinical:solid tumors, leukemia, lymphomas, and some brain cancers
POLYARTERITIS NODOSA
WEGENERS, MICROSCOPIC POLYANGIITIS
Toxicity: myelosuppression, hemorrhagic cystitis,
Partially prevented with MESNA (bind acrolein)
Nitrosoureas (carmustine, lomustine, semustine, streptozocin)
MOA: cross BBB
Cross link DNA
Clinical: brain tumors
Toxicity: convulsins, dizziness, ataxia
Busulfan
MOA: cross links DNA
Clinical: CML
Ablate bone marrow before transplantation
Toxicity: myelosuppression, pulmonary fibrosis, hyperpigmentation
Vincristine, vinblastine
MOA: bind B-tubulin inhibiting its polymerizatin into microtubles preventing mitotic spindle formation
M-phase arrest
Clinical: solid tumors, leukemias and lymphomas
Toxicity: Vincristine-neurotoxicity (areflexia, peripheral neuritis), paralytic ileus
Vinblastine-bone marrow suppression