Treatments for Anemia Flashcards
what are the treatment options for anemia?
• Iron Supplements oral: Ferrous Sulfate Ferrous Gluconate • Folic Acid • Vitamin B 12 (Cyanocobalamin) • Epoetin Alpha (Epogen, Procrit) • Darbepoetin (Aranesp)
what type of patients are treated prophylactically for anemia & why?
CKD patients
-prone to anemia d/t hemodialysis
what forms do iron supplements come in? which is the cheapest?
oral- cheapest
IM
IV
can patients with hemosiderosis or hemochromatosis
be given iron supplements?
No
Due to risk for iron overload syndromes
what are the most commonly used PO forms of iron supplements?
Ferrous Sulfate
> Elemental iron dose: 50-100mg PO TID
> Pure salt form: Ferrous Sulfate 320/324/325mg PO TID
Ferrous Gluconate
what is the dosing for ferrous salts in normal, healthy adults?
Ferrous Sulfate 320/324/325mg PO TID
what are the symptoms of iron supplements such as ferrous sulfate & ferrous gluconate?
constipation- most common nausea epigastric pain vomiting diarrhea black stools anorexia
what types of medications interact w/ ferrous salts & how do they interact w/ them?
dec absorption and effectiveness of iron d/t required acidic environment for Fe
- Calcium
- Antacids
- PPIs
- levodopa
- fluoroquinolones
- Tetracyclines
- PCNs
- Vit E
- Levothyroxine
when prescribing patients to take iron supplements, how should you instruct them?
take w/ food at night
what foods may impair oral iron absorption & can interact w/ iron supplements?
cheese, coffee, milk, yogurt, whole grain breads,
eggs
what vitamin increases the absorption of iron?
Vitamin C
-allows an acidic environment which enables iron to be absorbed
what are the benefits of using anhydrous ferrous sulfate & what are the disadvantages?
pro: once a day dosing d/t 30% elemental iron = extended release & increased compliance
con: expensive & higher cost than ferrous sulfate
what are the advantages of ferrous sulfate?
low cost w/ good effectiveness & tolerability
what iron supplement is given to patients w/ renal insufficiency & patients on dialysis?
Nu-Iron 150, Niferex -> polysaccharide-iron complex
pro: 100% elemental iron -> not dialyzed out as easily
tasteless, odorless
similar bioavailability to ferrous sulfate
con: VERY expensive
what does the amount of iron absorbed in the body depend on?
content of Heme/Fe (meats vs. veggies/legumes)
calcium
what are vegetarian sources of iron that increase absorption of Fe?
- Legumes (lentils, chick peas, lima beans)
- Grains (quinoa, brown rice)
- Some Veggies (swiss chard, collard greens)
- Nuts and Seeds (cashews, pinenuts)
why can’t ferrous sulfate tablets be crushed?
iron will not reach the stomach & it will eat stomach lining = decreased absorption d/t inactivation
why does PO iron require several months of administration?
Fe storage takes about 3-6 months to be restored
what are contraindications when giving iron?
PUD regional enteritis ulcerative colitis repeated blood transfusions hemochromatosis hemosiderosis
what are the advantages of administering IV iron?
- rapid correction of anemia & resolution of sx
- can administer large doses (up to 1000mg of elemental Fe) in single infusion
- assured compliance
- no GI side effects
what are the disadvantages of administering IV iron?
- requires monitoring d/t anaphylaxis
- equipment & medical personnel needed in case there are rxns
- higher initial cost
if a pt that is taking iron supplements comes into the office reporting black stools, what can this indicate?
GI bleed
what type of iron supplement can be prescribed to pregnant patients?
what would you prescribe with it to optimize its effects?
what are adverse effects related to pregnancy with taking iron?
- Ferrous Sulfate
- neuro deficits in infants & children
- Vitamin C
what are the types of folic acid supplements & what is the OTC dosage? what is the Rx dose?
folic acid
folate
folvite
OTC: 400mcg
Rx: 1mg/day
why are folate supplements given to pregnant patients?
prevention of neural tube defects (NTD)
what is the MOA of folate deficiency?
-decreased synthesis of: amino acid purine pyrimidine -results in decreased DNA & RNA synthesis = macrocytic/megaloblastic anemia
what vitamin must be given to patients that are prescribed methotrexate?
folic acid (vit B9)
what is the MOA of folic acid?
Stimulates production of protein synthesis necessary for RBC, WBC and platelet formation
where in the body is folic acid metabolized and how long is it stored?
Converted by the liver to an active metabolite,
dihydrofolate reductase
Stored in liver for 4 months
what drugs inhibit folate synthesis, absorption, and/or metabolism?
macrolides:
- erythromycin
- fofsamycin
bactrim
ethanol
phenytoin (Dilantin)
what conditions can lead to deficient B12 absorption?
Crohn’s disease cystic fibrosis (malabsorption due to insufficient alkalinization of the duodenal contents)
*also- vegan diet x5 years
What lifestyle habits/changes can lead to B12 deficiency?
Strict vegans
Vegetarian diet in pregnancy
Patients that have had gastric bypass surgery
What agents block & inhibit absorption of B12?
Neomycin (aminoglycoside PO)
Metformin
PPIs such as omeprazole
H2 receptor antagonists such as famotidine (Pepcid)
What is required for vitamin B12 to be absorbed?
Acidic environment in the stomach & intrinsic factor
What is given to treat patients with pernicious anemia & why?
B12 shots due to lack of intrinsic factor from destruction of gastric parietal cells
Monthly shots = better compliance due to reduction of pill load
Vitamin b12 is a _ soluble substance
Water
If a patient on colchicine is b12 deficient, what should you do?
D/c colchicine → b12 absorption normalizes because colchicine reduces quantity of available B12 receptors
What is the recommended oral dose for b12 deficiency?
1000 mcg PO qd
* not suitable for severe B12 deficiency
What is the half life for B12 & where is it stored for how long?
6 days - 400 days in the liver
What is the IM/SC dosage for vitamin b12 (Cyanocobalamin) shots?
1000 mcg per month
What is the man made form of vitamin b12 & what is it available in?
cyanocobalamin
- Tablets
- Injection → pernicious anemia or lack of capacity for oral administration
- Nasal Spray
What is the most concerning adverse reaction for cyanocobalamin & how does this happen?
Hypokalemia with heavy dosing
B12 pushes potassium into cells reduction of serum potassium due to intracellular shift
What is used for anemic patients with end stage renal disease & when is it given?
Erythropoietin & epoetin during dialysis
* also given to chemo & HIV patients on zidovudine
When is erythropoetin contraindicated?
Nonspecific anemia & uncontrolled hypertension
What are the two available products for erythropoietin & Epoetin?
Epoetin: epogen & procrit
Darbepoetin; aranesp
What should be done before giving erythropoietin & what is the MOA?
Obtain retic count
Stimulates the release of reticulocytes
Dose dependent → retic count will first rise followed by H&H
What is the half life of erythropoietin & why is this important for dialysis patients?
4-13 hours
Dialysis patients will not need continuous infusion → received once a week
what is the most adverse reaction of erythropoietin & how does this happen?
Hypertensive crisis & seizures
> high doses given too quickly in patients w/ prior hx of uncontrolled HTN
> IV vs. IM/subq
how is erythropoietin dosed and what is it based on?
Initial dose is weight based -> interval dosing d/t half life
» adjusted based on Hgb level
what patients should be cautioned (risk vs benefit) before giving erythropoietin?
> patients with prior venous thrombosis or prolonged immobilization
cancer patients
what is the long acting version of erythropoietin?
Darbepoetin IV or subcutaneously
how often are patients w/ CKD (not on dialysis) given Darbepoetin?
IV or subq once every 4 weeks
how often are dialysis patients given Darbepoetin?
once a week every 2 weeks (infusion of subq)
why is Darbepoetin not intended for STAT or Emergency use?
-delayed onset of action
|»_space;> patients should be given infusion for emergencies d/t expenses
what substance is in greens & some grains which inhibits the absorption of nonheme iron? what are some examples that are common in diets?
oxalates
> spinach
> kale
what are causes of folate (vitamin B9) deficiency?
poor intake pregnancy alcoholism MTX use depression & nursing homes -> pts do not eat
