Class Explorer · Hematology
Hematinics
Replacement of the substrates of erythropoiesis. Each one corrects a different deficiency, and giving the wrong one is a way to delay the diagnosis.
Members
Ferrous sulfateCheap, effective, badly tolerated, and best given every other day.Cyanocobalamin (vitamin B12)Replace it before folate, or the blood improves while the spinal cord does not.Folic acidNever given before B12 has been checked.
Also in this class: Ferrous fumarate · Ferric gluconate · Iron sucrose (IV). Full pages arrive as the library grows.
Compare the members
Ferrous sulfate
- Corrects
- Microcytic, iron deficiency
- Note
- Alternate-day dosing absorbs better
Cyanocobalamin (vitamin B12)
- Corrects
- Macrocytic, B12 deficiency
- Note
- Check before giving folate
Folic acid
- Corrects
- Macrocytic, folate deficiency
- Note
- Never before excluding B12 deficiency
Shared across the class
- Indications
- Nutritional anemias · Deficiency states
- Adverse effects
- Gastrointestinal upset (iron) · Injection-site reactions
- Contraindications
- Iron overload states · Undiagnosed anemia, where treating first buries the cause
- Monitoring
- Reticulocyte rise at about one week as proof of response · Hemoglobin and mean cell volume at four to eight weeks · Ferritin to confirm stores are replete before stopping iron
What makes each agent different
- Iron corrects a microcytic anemia; B12 and folate correct a macrocytic one. The mean cell volume is the first branch point and it is cheap.
- Giving folate to a B12-deficient patient corrects the blood count while the neurological damage continues. That is the single most important sequencing rule in this class.
Alternate-day iron dosing produces better absorption than daily dosing, because a dose raises hepcidin for about 24 hours and blocks the next one.
Iron deficiency in an adult male or a postmenopausal female is a gastrointestinal investigation until proven otherwise; the tablet is the easy half of the response.
Last reviewed 2026-08-16 · Goodman & Gilman's The Pharmacological Basis of Therapeutics, 14th ed.