252 Pharmacology - Anemia Flashcards
What is one of the primary functions of bones/
The formation of new blood cells (hematopoiesis).
What types of cells are created as part of hematopoeisis?
- Red blood cells (RBCs)
- White blood cells (WBCs)
- Platelets
How much of a red blood cell is made up of hemoglobin?
More than one third
What are erythrocytes?
Red blood cells (just another name for them)
What is erythropietin?
A hormone secreted by the kidneys that increases the rate of production of red blood cells in the bone marrow in response to decreasing oxygen levels in the tissues.
What is globin?
The protein part of the hemoglobin molecule (see later); the four different structural chains most often found in adults are the α1, α2, β1, and β2 chains.
What is heme?
Part of the hemoglobin molecule; a nonprotein, iron-containing pigment.
What is hemoglobin?
A complex protein–iron compound in the blood that carries oxygen to the cells from the lungs and carbon dioxide away from the cells to the lungs.
What are hemolytic anemias?
Anemias resulting from excessive destruction of erythrocytes.
Define hypochromic.
Pertaining to less than normal colour; usually describes a red blood cell with decreased hemoglobin content and helps further characterize anemias associated with reduced synthesis of hemoglobin.
What is a microcytic cell?
Pertaining to or characterized by smaller than normal cells.
What is pernicious anemia?
A type of megaloblastic anemia usually seen in older adults and caused by inadequate intestinal absorption of vitamin B12 (cyanocobalamin) due to lack of availability of intrinsic factor.
What are reticulocytes?
Immature erythrocytes characterized by a meshlike pattern of threads and particles at the former site of the nucleus.
What are spherocytes?
Small, globular, completely hemoglobinated erythrocytes without the usual central concavity or pallor.
What drug is a biosynthetic form of the natural hormone erythropoietin?
epoetin alfa
What medication is used for treatment of anemia associated with end-stage renal disease, chemotherapy-induced anemia, and anemia associated with zidovudine therapy
epoeitin alfa
What must be present in the body for epoetin alfa to work?
Iron and bone marrow function
What is the longer-acting form of epoetin alfa called?
darbepoetin (Aranesp®)
What is the mode of action of epoetin alfa?
Promotes the synthesis of RBCs by stimulating RBC progenitor cells in the bone marrow
What is the advantage of darbepoetin over epoetin?
Darbepoetin is longer acting and requires fewer injections.
When is the use of epoetin and darbepoetin contraindicated?
- In cases of uncontrolled hypertension
- When Hgb levels are above 100 mmol/L for cancer patients
- When Hgb levels are above 130 mmol/L for patients with kidney disease
- Head or neck cancers or patients at risk for thrombosis
What are the most frequent side effects of epoetin alfa?
- Hypertension
- fever
- headache
- pruritis
- rash
- nausea
- vomiting
- arthralgia
- injection site reaction
How are epoetin and darbepoetin given?
Injection; IV or SUBCUT
What are some key characteristics of iron?
- Essential mineral in the body
- Oxygen carrier in hemoglobin and myoglobin
- Stored in the liver, spleen, and bone marrow
- Deficiency results in anemia
What groups require the highest amount of iron?
- Women
- Children
They are the groups most likely to develop iron-deficient anemia
What are some dietary sources of iron?
- Meats
- Certain vegetables and grains
- Beans
- Dried fruits
- Eggs
*** These forms must be broken down by gastric juices before the iron can be absorbed ***
Which foods may enhance iron absorption?
- Orange juice
- Veal
- Fish
- Ascorbic acid
Which foods might impair iron absorption?
- Eggs
- Corn
- Beans
- Many cereal products containing phytates
True or false: Supplemental iron may be given as a single drug or as part of a multivitamin preparation.
True
How is iron supplemented orally?
With ferrous salts.
List the various oral ferrous salts?
- ferrous fumarate
- ferrous gluconate
- ferrous sulphate
When might an IV preparation of iron be used?
- When a patient can’t tolerate oral iron
- if rapid replenishment is necessary
- if oral iron therapy is unsuccessful
List the parenteral iron products.
- iron dextran (Dexiron®, Infufer®)
- iron sucrose (Venofer®)
- ferric gluconate (Ferrlecit®)
What are the common adverse effects of iron?
- 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.
What happens with iron once it is in ferrous form and in the bloodstream?
Iron is used in the bone marrow to make hemoglobin and the excess is stored as ferritin, primarily in the liver and some in the spleen.
What are contraindications of iron products?
- known drug allergy
- hemochromatosis (iron overload)
- hemolytic anemia
- any other anemia not associated with iron deficiency
Do older individuals tend to respond slower or faster to iron supplementation?
slower
How is iron overdose treated?
Symptomatic and supportive measures:
- Suction and maintenance of airway
- Correction of acidosis
- Control of shock and dehydration with IV fluids, blood, oxygen, and vasopressors
- GI tract is decontaminated via whole-bowel irrigation
- Chelation therapy with IV deferoxamine mesylate
At what serum iron concentration places the patient at serious potential for toxicity?
54 mmol/L
What is the treatment in patients with severe symptoms of iron intoxication, such as coma, shock, or seizures?
chelation therapy with deferoxamine mesylate
What decreases the absorption of iron?
- antacids
- calcium
What can iron preparations decrease the absorption of?
- Certain antibiotics, including tetracyclines and quinolones
What are contraindications of iron preparations?
- Ulcerative colitis
- Regional enteritis
- Conditions involving excessive stores of iron in the body
- Peptic ulcer disease
- hemolytic anemia
- cirrhosis
- gastritis
- esophagitis
What are some goals of iron therapy?
- Normal hemoglobin and hematocrit levels
- Improved energy levels
What are normal ranges for hemoglobin in females and males?
Females: 120 - 160 g/L
Males: 140 - 180 g/L
What is the normal hematocrit level for males and females?
0.37 to 0.47 volume fraction
What type of iron supplement may cause anaphylactic reactions, including major orthostatic hypotension and fatal anaphylaxis?
iron dextran
What approach is usually taken with iron dextran?
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
What is ferric gluconate indicated for?
Indicated for repletion of total body iron content in patients with iron deficiency anemia who are undergoing hemodialysis
Is a test dose required for ferric gluconate?
No
What dose of ferric gluconate is associated with increased adverse events, including abdominal pain, dyspnea, cramps, and itching?
doses higher than 125 mg
Which iron salt contains the largest amount of iron per gram of salt consumed?
ferrous fumarate
What is the most frequently used form of oral iron?
ferrous sulphate
Who is iron sucrose indicated for?
Patients with chronic renal disease
What is the most common side effect of iron sucrose?
Hypotension resulting from infusion rate. large doses of iron sucrose are infused over 2.5 to 3.5 hours.
What are some key characteristics of 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.
What are dietary sources of folic acid?
- dried beans
- peas
- oranges
- green vegetables
What is folic acid used for?
- erythropoiesis
- synthesis of nucleic acids (DNA and RNA)
Is folic acid active in the ingested form?
No, must be converted first
Indications of folic acid
- anemias caused by folic acid deficiency
- prevention of neural tube defects in pregnancy (start 1 month prior)
- Tropical sprue
Contraindications of folic acid
- known drug allergy
- any anemia not resulting from folic acid anemia
What are adverse effects of folic acid
They are rare, but are as follows:
- allergic reaction
- yellow discoloration of urine
What other things can cause signs of folic acid deficiency (but are not affected by folic acid adminsitration)
- oral contraceptives
- corticosteroids
- sulfonamides
- dihydrofolate reductase inhibitors
- antibiotic trimethoprim
What is cyanocobalamin used to treat?
- Used to treat pernicious anemia and other megaloblastic anemias
- Administered orally or parentally.
- Usually administered by deep intramuscular injection to treat pernicious anemia
How can patients avoid esophageal corrosion?
To avoid esophageal corrosion, patients should remain upright for up to 30 minutes after taking oral iron doses
How is iron dextran administered?
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.
What are we worried about with anemia?
Not enough oxygen; not adequate tissue perfusion.
Are oral iron salt supplementation types interchangeable?
No
