Pharm Heme/onc Flashcards
what are the two main categories of hematologic drugs?
supplements
growth factor stimulants
what are the three categories of drugs under the supplements branch of hematologic drugs?
hematinics: iron
Vitamin B12
nutritionals: folic acid
what are the two categories of drugs under the hematologic growth factor stimulants?
erythrocyte stimulating agents: erythropoetin
myeloid growth factor: filgastrin
what is iron bound to in the blood?
transferrin
when iron (FE) stores are high, where is it diverted to for additional storage? where is it initially stored before going there?
diverted to intestinal mucosal cells
initial stores are in
macrophages in the liver, spleen, and bone
what is ferritin made out of?
iron and apoferritin
what percent of ferrous iron dose is absorbed daily if the pt has ADEQUATE IRON STORES? what about if this same patient had DEPLETED stores?
if adequate iron stores: 5-10%
if depleted, maximum: 25-30%
what is the goal for elemental iron daily?
200-400 mg
what is the max incorperate of iron?
50-100 mg daily
Caution: what should you caution about children and iron?
overdoses are lethal in children
what percent of iron is absorbed?
5-30% depending on the stores
5-10% if stores are adequate
25-30% if stores are depleted
what two things decrease iron absorption?
food and achlorhydria
- age decreases RBC absorption
- impacted by proton pump inhibitors
what part of the intestine absorbes FE via what mechanism
duodenum, jejunum via divalent metal transporter 1 (DMTI)
what is iron administered as?
FESO4
if you administer 325 mg of FESO4 how much elemental iron is released?
65mg
How long does it take for reticulocytosis and increase in hemoglobin/hct after giving pt iron?
reticulocytosis: 5-10 days
increase in hgb: 4-6 weeks
these patients are sicker so it takes longer to see increase in hgb
what happens to the rate of absorption as the FE stores replenish with FESO4 administration?
the rate of absorption decreases
what is the max amount of time you should take iron?
6 months
what is the maximum Hgb on treatment?
12 gm/dl
how long does it take a erythrocyte stimulating agent (ESA) to increase the number of reticulocytes? how long to increase the hemoglobin (Hbg) and hematocrit (Hct) when treated with ESA?
5-10 days to increase # of reticulocytes
2-6 weeks to increase hgb and hct
if giving someone erythropoeitin, the patient is most likely a lot sicker, which is why it takes the Hbg and Hct so much time to increase compared to the normal 2-4 weeks in normal patient
What two things might a patient need to take/increase when being treated with a erythrocyte stimulating agent (ESR)?
iron supplementation
anti-coagulant
think about it…more cells!
what are the four major classes of anti-coagulant drugs?
- indirect thrombin inhibitors
- direct thrombin inhibitors
- coumarin drugs
- direct oral Xa inhibitors
what are the three major classes under anti-hemostasis drugs?
- anti-coagulant drugs
- fibrinolytic drugs
- anti-platelet drugs
what does “white” clot mean?
arterial clots form around activated platelets
what does “red” clots mean?
venous clots form around activated fibrin and RBCs
what drugs are used for arterial clots (white clots)?
anti-platelet drugs
what drugs are used for venous cloths (red cloths)?
anti-coagulants
the prothrombine time PT is a function of what? what factors does it include?
extrinsic factors, primarily k dependent factors
what is the INR?
normalizes the PT across different labs
the active partial thromboplastin time aPTT is a function of what? what factors does it intclude?
intrinsic pathways, both vitamin k dependent factors and contact activated factors
what are the four indirect anticoagulant drugs?
- unfractioned heparin
- low molecular weight heparin (LMWH)
- fonaparinux
- protamine sulfate
what is the name of the oral and IV direct thrombin inhibitors?
dabigatran (PO)
argatroban (IV)
what are the benefits to using a oral direct thrombin inhibitor?
- rapid onstet
- halflife=minutes
- stable pK (body on drug) and bioavaliability
- doesn’t interact with P-450 interacting drugs
what is the first and common clotting factor between the intrinsic and extrinsic clotting pathways?
Factor X
what does factor Xa (activated 10) do?
catalyzes the conversion of prothrombin (II) to thrombin (Ila)
explain where the direct factor Xa inhibitor “rivaroxaban” is metabolized and excreted? by what mechanism? what else is it a substrate of?
70% liver metabolism by CYP34A/5
30% renally excreted
substrate of paraglyocoprotein pump system
what percentage of warfarin is bound in serum?
99%
what type of mixture is warfarin? which is more effective?
racemic mixture
S-warfarin is 4x more potentent than R-warfarin
must consider this in dx-dx reactions
what does warfarin act on?
vitamin K dependent coagulation factors
what does warfarin produce?
biologically inactive molecules
can people be genetically resistant to warfarin? what is this based on?
yes
mutation changes to vitamin K epoxide reductase (VKOR)
what is the delay in drug onset of warfarin? and what is the delay in effect?
8-12 hour delay in drug onset, 48-72 hour delay in effect
what is interesting about warfarin and pregnancy?
crosses placenta readily and is CATEGORY X!!!!!
what are the two fibrinolytic drugs?
streptokinase, alteplase
how long would it take to see the hgb increase when giving oral iron?
2-4 weeks!
in a otherwise normal patient, it would be closer to 2 weeks
does dabigatran require any formal monitoring plan?!
NO!!! it doesn’t!!! give it and don’t have to monitor it!
Although you don’t have to monitor dabigatran, what are the three things you need to check before prescribing to a patient?
H&H, CrCl, and aPTT
how does iron deficient anemia present? what things can cause it?
vegan diet excessive NSAID use (ibuprofen) menorrhagia (heavy periods) fatigue with minimal excertion pale nail beds and skin
what do you treat iron deficient anemia with? whats the dosing?
FeSO4
325 mg 3x daily
what is important to do when treating patients with FeSO4?
uptitrate, can bind people up badly!
can be harsh on the stomache so give 2 times daily and then three, if ELDERLY, start with 1 time daily
what should you do for a elderly patient starting FeSO4?
start 1x a day and then up titrate to get to 2x, and 3x if they can tolerate it. might cause too much N/V/D/contipation in elderly so better to start small!
why do you need to give FeSO4 so much or three times a day?
because by the time you pick up on the anemia, the body has already depleted the stores so the body is unable to conpensate for that. they have gone through all the stores so it takes a lot to get rid of the symptoms and replenish the stores!
how long are people usually required to take FeSO4 for?
6 months
Case: if someone has menorrhagia and have iron deficient anemia what do you need to consider?
need to consider their birth control options and consider uping the dose to decrease the amount of bleeding which causes decreased risk of anemia! helps stablize iron levels!
if someone has iron deficient anemia, what are the two main things you want to consider for reasons?
diet (green and leafy)
bleeding (GI/menorrhagia)
what is the most common cause of blood loss for a otherwise healthy person?
blood loss
if treating a patient with FeSO4 for iron deficient anemia, what should you monitor and in what time frame?
reticulocytes after 2 weeks
H+H after a month
interesting: what is the #1 reason people stop taking FeSO4?
GI complications
N/V/D/constipation
iron deficient anemia, the RBCs appeare….
MICROCYTIC!
B12/folate deficient anemia, the RBCs appeare….
MACROCYTIC!! since dont’ have all the components they are release prematurely!
can you have both B12/folate anemia and iron deficient anemia at the same time?
Yes! you would see micro and macrocytic RBC at the same time!
what does FeSO4 stand for?
ferrous sulphate