chapter 55 anemia drugs - week 3 Flashcards
hematopoiesis
Formation of new blood cells
Red blood cells (RBCs)
White blood cells (WBCs)
Platelets
rbcs
- Manufactured in bone marrow
- Immature RBCs are reticulocytes.
- Lifespan is 120 days.
More than one third of an RBC is made of hemoglobin.
Heme: red pigment; contains iron
Globin: protein chain
anemias
Maturation defects
* Cytoplasmic
* Nuclear
* Excessive destruction of RBCs (hemolytic anemias)
* Intrinsic RBC abnormalities
* Extrinsic mechanisms
erythropoiesis stimulating agents
epoetin alfa (Eprex®)
* Biosynthetic form of the natural hormone erythropoietin
* Used for treatment of anemia associated with end-stage renal disease, chemotherapy-induced anemia, and anemia associated with zidovudine therapy
* Medication is ineffective without adequate body iron stores and bone marrow function.
* Most patients receiving epoetin alfa need to also receive an oral iron preparation.
* Longer-acting form of epoetin is called darbepoetin (Aranesp®)
* Contraindications: drug allergy; uncontrolled hypertension; hemoglobin levels that are above 100 mmol/L for cancer patients and 130 mmol/L for patients with kidney disease; head and neck cancers; risk of thrombosis
* Most frequent adverse effects: hypertension, fever, headache, pruritus, rash, nausea, vomiting, arthralgia, and injection site reaction
iron
- Essential mineral in the body
- Oxygen carrier in hemoglobin and myoglobin
- Stored in the liver, spleen, and bone marrow
- Deficiency results in anemia
- Dietary sources: meats, certain vegetables and grains
- Dietary iron must be converted by gastric juices before it can be absorbed.
foods that enchance iron absorption
- Orange juice
- Veal
- Fish
- Ascorbic acid
some food impair iron absorption
- Eggs
- Corn
- Beans
- Cereal products containing phytates
supplemental irons
- Supplemental iron may be given as a single drug or as part of a multivitamin preparation.
- Oral iron preparations are available as ferrous salts.
- ferrous fumarate (Femiron®), ferrous gluconate, ferrous sulphate (FeSO4)
Parenteral - iron dextran (Dexiron®, Infufer®)
- iron sucrose (Venofer®)
- ferric gluconate (Ferrlecit®)
- ferumoxytol (Feraheme®)
iron indications
- Prevention and treatment of iron deficiency syndromes
- Administration of iron alleviates the symptoms of iron deficiency anemia, but the underlying cause of the anemia should be corrected.
iron adverse effects
- Most common cause of pediatric poisoning deaths
- Causes nausea, vomiting, diarrhea, constipation, and stomach cramps and pain
- Causes black, tarry stools
- Liquid oral preparations temporarily discolour teeth.
- Injectable forms cause pain upon injection.
iron toxicity
- Symptomatic and supportive measures
- Suction and maintenance of the airway; correction of acidosis; control of shock and dehydration with IV fluids or blood, oxygen, and vasopressors
- In patients with severe symptoms of iron intoxication, such as coma, shock, or seizures, chelation therapy with deferoxamine mesylate is initiated.
prenatal iron
Iron dextran (Dexiron, Infufer)
* May cause anaphylactic reactions, including major orthostatic hypotension and fatal anaphylaxis
* A test dose of 25 mg of iron dextran is administered before injection of the full dose, and then the remainder of dose is given after 1 hour.
* Used less frequently now; replaced by newer products ferric gluconate and iron sucrose
ferric gluconate (Ferrlecit)
* Indicated for repletion of total body iron content in patients with iron deficiency anemia who are undergoing hemodialysis
* Risk of anaphylaxis is much less than with iron dextran, and a test dose is not required.
* Doses higher than 125 mg are associated with increased adverse events, including abdominal pain, dyspnea, cramps, and itching.
folic acid
- Water-soluble, B-complex vitamin
- Essential for erythropoiesis
- Primary uses
- Folic acid deficiency
- During pregnancy, to prevent neural tube defects
- Malabsorption syndromes are the most common causes of deficiency
- Should not be used until actual cause of anemia is determined
- May mask symptoms of pernicious anemia, which requires treatment other than folic acid
- Untreated pernicious anemia progresses to neurological damage.
cyanocobalamin (vitamin B12)
- Used to treat pernicious anemia and other megaloblastic anemias
- Administered orally or parentally.
- Usually administered by deep intramuscular injection to treat pernicious anemia
nursing assessment
- Assess patient history and medication history, including drug allergies.
- Assess potential contraindications.
- Assess baseline laboratory values, especially hemoglobin, hematocrit, reticulocytes, and others.
- Obtain nutritional assessment.
ferrous salts considerations
- Ferrous salts are contraindicated for patients with ulcerative colitis, peptic ulcer disease, liver disease, and other gastrointestinal disorders.
- Keep away from children, because oral forms may look like candy.
- Iron dextran is contraindicated in all anemias except for iron-deficiency anemia.
liquid irons considerations
- For liquid iron preparations, follow the manufacturer’s guidelines on dilution and administration.
- Instruct the patient to take liquid iron preparations through a straw to avoid staining tooth enamel.
oral forms of iron nursing considerations
- Oral forms of iron should be taken between meals for maximum absorption but may be taken with meals if gastrointestinal distress occurs.
- Oral forms should be given with juice but not with milk or antacids.
- avoid esophageal corrosion, patients should remain upright for up to 30 minutes after taking oral iron doses.
- Patients should be encouraged to eat foods high in iron and folic acid.
iron dextran nursing considerations
- For iron dextran, a small test dose should be given, If there is no reaction after 1 hour, the remainder of the dose can be given.
- Administer the dose deeply into a large muscle mass, using the Z-track method.Give IV doses of iron dextran carefully and according to the manufacturer’s instructions.
- Have resuscitative equipment available in case of an anaphylactic reaction.
folic acid nursing considerations
- Determine the cause of anemia before administering folic acid.
- Administer oral folic acid with food.
- Folic acid is available for both oral and injectable use
other nursing considerations
- Monitor therapeutic responses.
- Improved nutritional status
- Increased weight, activity tolerance, well-being
- Absence of fatigue
- Monitor adverse effects.v
