Investigation of the underlying cause of the anaemia is essential.

Folic acid

• Tablets 400micrograms (£3.27 = 90 tablets)
• Tablets 5mg (£0.68 = 28 tablets)
• Oral solution sugar free 2.5mg/5ml (£9.16 = 150ml)

Indications and dose

• Folate-deficient megaloblastic anaemia, oral, 5mg daily for 4 months (until term in pregnant women); up to 15mg daily may be required in malabsorption states
• Prevention of neural tube defects, see Neural tube defects (prevention in pregnancy)
• Prevention of methotrexate-induced side-effects (off-label use), oral, 5mg at least once weekly (more frequent dosing is often routinely recommended, refer to individual methotrexate shared care guidelines / specialist advice). Folic acid should be taken at least 24 hours after previous methotrexate administration. Be aware that methotrexate and folic acid tablets look alike.
• Prophylaxis in chronic haemolytic states, oral, 5mg every 1–7 days depending on underlying disease
• Prophylaxis of folate deficiency in dialysis, oral, 5mg every 1–7 days

Notes

1. Folic acid should not be used in undiagnosed megaloblastic anaemia unless vitamin B12 is administered concurrently, otherwise neuropathy may be precipitated
2. There is no justification for prescribing multiple-ingredient vitamin preparations containing vitamin B12 or folic acid

Hydroxocobalamin

• Injection 1mg/1ml (£2.37 = 1ml amp)

Indications and dose

• Pernicious anaemia and other macrocytic anaemias without neurological involvement, initially 1mg 3 times a week for 2 weeks then 1mg every 3 months
• Pernicious anaemia and other macrocytic anaemias with neurological involvement, initially 1mg on alternate days until no further improvement, then 1mg every 2 months
• Prophylaxis of macrocytic anaemias associated with vitamin B12 deficiency, 1mg every 2–3 months
• Long-term supplementation following gastric bypass or sleeve gastrectomy: 1mg every 3 months

Notes

1. Hydroxocobalamin injections are normally given every three months; more frequent administration is rarely justified.
2. MHRA Drug Safety Update (December 2023): Vitamin B12 (hydroxocobalamin, cyanocobalamin): advise patients with known cobalt allergy to be vigilant for sensitivity reactions