STEPTRACKERPHARMACOLOGY + HEMATOLOGY | HEMATOLOGY | HIGH-YIELD REVIEW

Drugs for Anemia & Blood Cells

Replace what's missing (iron, B12, folate), stimulate production (growth factors), or protect cells from damage (hydroxyurea, chelators) — and know which drugs cause blood dyscrasias.

FOCUS ON
Iron: oral ferrous sulfate (GI upset, constipation, black stools; absorption ↑ with vitamin C, ↓ with PPIs, calcium, tetracyclines); IV iron for malabsorption/CKD. Iron overdose (children) → GI hemorrhage, metabolic acidosis, liver failure → deferoxamine. Chronic iron overload (transfusions) → deferoxamine, deferasirox, deferiprone (agranulocytosis). B12: IM cyanocobalamin (or high-dose oral) for pernicious anemia; folate masks B12 deficiency (fixes anemia, not neuropathy). Epoetin/darbepoetin: CKD, chemotherapy anemia; HTN, thrombosis. Filgrastim/pegfilgrastim (G-CSF), sargramostim (GM-CSF): neutropenia; bone pain. Romiplostim, eltrombopag (TPO agonists): ITP. Hydroxyurea: ↑ HbF in sickle cell; macrocytosis, myelosuppression. Voxelotor, crizanlizumab, L-glutamine: sickle cell. Desmopressin: ↑ vWF and VIII (mild hemophilia A, type 1 vWD).
DRUG
MECHANISM
USE
ADVERSE · NOTES
Ferrous sulfate
Oral Fe²⁺, absorbed in duodenum (DMT1)
Iron deficiency anemia
Constipation, dark stools · reticulocytes rise in ~1 week
IV iron
iron sucrose, ferric carboxymaltose
Bypasses gut
CKD on EPO, IBD, malabsorption, intolerance
Hypersensitivity (iron dextran), hypophosphatemia
Deferoxamine
Chelates free iron (IV/SC)
Acute iron poisoning, transfusional overload
Vin rosé urine, Yersinia infection, hearing/vision loss
Deferasirox · deferiprone
Oral iron chelators
Chronic overload (thalassemia)
Deferasirox: renal, hepatic, GI · deferiprone: agranulocytosis
Cyanocobalamin · hydroxocobalamin
Replaces B12 (methylmalonyl-CoA mutase, methionine synthase)
Pernicious anemia, ileal resection, vegans · hydroxocobalamin for cyanide
Hypokalemia during brisk response
Folic acid
THF for DNA synthesis
Folate deficiency, pregnancy, hemolytic anemia, methotrexate users
Masks B12 deficiency — neuro damage continues
Leucovorin (folinic acid)
Reduced folate, bypasses DHFR
Methotrexate rescue; with 5-FU (↑ effect)
Also given with pyrimethamine to protect host marrow
Epoetin alfa · darbepoetin
EPO receptor agonists
Anemia of CKD, chemotherapy, zidovudine
Hypertension, thrombosis, tumor progression; check iron
Filgrastim · pegfilgrastim · sargramostim
G-CSF · GM-CSF
Chemotherapy neutropenia, stem-cell mobilization
Bone pain, splenic rupture (rare)
Romiplostim · eltrombopag
Thrombopoietin receptor agonists
Chronic ITP, aplastic anemia (eltrombopag)
Hepatotoxicity (eltrombopag), marrow fibrosis
Hydroxyurea
Ribonucleotide reductase inhibitor → ↑ HbF
Sickle cell disease, polycythemia vera, essential thrombocythemia, CML
Myelosuppression, macrocytosis, teratogen
Desmopressin (DDAVP)
V2 agonist → endothelial vWF and factor VIII release
Mild hemophilia A, type 1 von Willebrand disease, uremic bleeding
Hyponatremia, tachyphylaxis
Drug-induced dyscrasias
Agranulocytosis: clozapine, carbamazepine, PTU/methimazole, dapsone, deferiprone, TMP-SMX · aplastic anemia: chloramphenicol, carbamazepine, felbamate, benzene
—
Fever + sore throat on these → check ANC

Mechanism — hydroxyurea in sickle cell

Hydroxyurea
→
↑ Fetal hemoglobin (HbF)
→
HbF doesn't polymerize with HbS
→
Fewer crises, less acute chest

Replacement checks

DEFICIENCY
REPLACE
CAUTION
Iron
Ferrous sulfate
Look for GI blood loss
B12
IM cyanocobalamin
Hypokalemia
Folate
Folic acid
Rule out B12 first
EPO (CKD)
Epoetin + iron
BP, thrombosis

How it's tested

COMMON CONFUSIONFolate corrects the megaloblastic anemia of B12 deficiency but not the subacute combined degeneration — always check B12.
THE TRAPIron tablets in a toddler: early vomiting, then an apparent recovery before shock, acidosis and liver failure — treat early with deferoxamine.
YOUR APPROACHType the anemia (micro, macro, normo) → replace or stimulate → monitor reticulocytes → check toxicity.

If you see… think…

Child with vomiting, bloody diarrhea after mother's vitamins → iron poisoning → deferoxamine
Raise HbF in sickle cell → hydroxyurea
Bone pain after neutropenia drug → filgrastim
Hypertension on drug for CKD anemia → epoetin
Bleeding in mild hemophilia A before dental work → desmopressin
Agranulocytosis with an oral iron chelator → deferiprone
Rescue from methotrexate toxicity → leucovorin
Chronic ITP refractory to steroids → romiplostim, eltrombopag (or rituximab)
Neuropathy worsens despite normal Hb on folic acid → untreated B12 deficiency
Aplastic anemia after an old antibiotic → chloramphenicol