Megaloblastic anaemia
Anaemia with increased MCV (>100 fL) and megaloblasts in bone marrow. Most common causes: vitamin B12 and/or folate deficiency, pernicious anaemia with B12 malabsorption, prolonged metformin, PPI or methotrexate therapy. Untreated, neurological symptoms appear (especially in B12 deficiency).
ICD-10 D53.12 drugs
Also known as: Macrocytic anaemia, B12 or folate deficiency anaemia
Drugs used for this condition
- ALevomefolate (L-methylfolate, 5-MTHF)First line · Active form of vitamin B9, ready for methylation reactionsLevomefolate corrects folate-deficiency megaloblastic anaemia. BSH 2014 recommends ruling out B12 deficiency before starting folate: correcting folate with undiagnosed B12 deficiency masks anaemia and allows neurological progression (subacute combined degeneration of the spinal cord). Dose 5 mg/day orally until haemoglobin recovers and MCV normalises. In most patients regular folic acid is equivalent.
- AMethylcobalaminFirst line · Active coenzyme form of vitamin B12Methylcobalamin corrects B12-deficiency megaloblastic anaemia. In newly diagnosed megaloblastic anaemia BSH 2014 recommends measuring both folate and B12 in parallel before starting therapy: correcting only one when both are deficient gives incomplete response and allows progression. Dose in marked anaemia: 1000 μg/day orally or IM, tapering to weekly then monthly.
How to read tiers A–F
Evidence tiers belong to the drug-indication pair, not to the drug as a whole: the same substance can be A for one condition and F for another.
- AStrong evidence – first or second line in international guidelines
- BRecommended in selected cases
- CStudy data contradict each other
- DBenefit not proven, no documented harm
- FDocumented harm, or risk without benefit