Source: Cook K, Ineck BA,
Lyond WL. Anemias. In: DiPiro, JT, Talbert RL, Yee GC, Matzke GR,
Wells BG, Posey LM. Pharmacotherapy: A Pathophysiologic Approach.
8th ed. http://www.accesspharmacy.com/content.aspx?aid=7999561.
Accessed June 12, 2012.
- Decreased oxygen-carrying capacity of blood characterized
by a decrease in hemoglobin (Hb) or red blood cells (RBCs)
- World Health Organization (WHO) definition
Hb <13 g/dL (<130 g/L; <8.07 mmol/L)
- Women: Hb <12 g/dL (<120 g/L; <7.45
- Major causes of folic acid deficiency
- Decreased absorption
- Increased requirements
- Hemolytic anemia
- Chronic inflammatory disorders
- Long-term dialysis
- Growth spurts
- Folate antagonists (e.g., methotrexate)
- Reduced folate absorption (e.g., phenytoin)
folic acid supplementation generally not recommended
- Macrocytic, megaloblastic anemia
- Folic acid is water-soluble vitamin.
destroyed by cooking
- Obtained through diet
- Minimum daily requirement: 50 to 100 mcg
requirements in pregnant/lactating women
- Body stores 5 to 10 mg, primarily in liver.
- Folate distributed to other body tissues via enterohepatic
- One of the most common vitamin deficiencies due to association
with excessive alcohol intake and pregnancy.
- Supplementation of folic acid needed to prevent neural
- Excessive alcohol intake
- Patients may be asymptomatic or have vague complaints.
- Symptoms of heart failure
- Sensitivity to cold
- Loss of skin tone
- Decreased mental acuity
Means of Confirmation
- Diagnosis is made based on laboratory test results.
- Reticulocyte count
- RBC folate concentration
- <150 ng/mL
- Better indicator of folic acid deficiency anemia than decreased
serum folate concentrations
- Serum homocysteine
- Figure 1 shows broad, general algorithm for diagnosis of anemia
based on laboratory data.
General algorithm for diagnosis of anemias. (↑,
increased; ↓ , decreased; A2,
hemoglobin A2; F, hemoglobin F; IF, intrinsic factor; MCV,
mean corpuscular volume; Pb, lead; TIBC, total iron-binding capacity;
WBC, white blood cells.) Reprinted with permission from Wells BG,
DiPiro JT, Schwinghammer TL, et al. Pharmacotherapy Handbook 8th
ed. New York: McGraw-Hill, 2012.
- Vitamin B12 deficiency (another cause of megaloblastic anemia)
- Myelodysplastic syndrome (another cause of macrocytic anemia)
- Reverse hematologic manifestations.
- Replace body stores.
- Prevent recurrence.
- Folic acid 1 mg by mouth daily for 4 months if underlying
cause is identified
- Deficiency due to malabsorption: 1–5 mg by mouth
- Encourage dietary supplementation.
- Reticulocyte count—Reticulocytosis begins in
- CBC—Hct normalizes within 2 months
- Rapid improvement in sense of well being