The maintenance B12 dose depends on whether the deficiency is diet related or not.
For people with B12 deficiency that is:
B12 deficiency not thought to be diet related
Eg: Pernicious anaemia, h/o total/partial gastrectomy or achlorhydria, inflammatory bowel diseases,
NICE 2019 Recommends: Administer hydroxocobalamin 1 mg intramuscularly every 2–3 months for life.
BSH advice during COVID19 pandemic:
Liver stores last for a year and hence levels of B12 will not be affected if one to two 3 monthly injection is omitted in patients on maintenance parenteral B12 supplements. BSH supports omitting B12 injections even in this group during COVID19 outbreak at least until the surge has passed.
For patients who report symptoms in the weeks preceding B12 injection, oral B12 50-150 micrograms per day can be offered as an alternative because there will still be sufficient absorption. If still very symptomatic then B12 injection can be given with clear understanding that the interaction with healthcare increases transmission risk of COVID19. We suggest taking the opportunity to measure B12.
B12 deficiency thought to be diet related
NICE 2019 Recommends:
Advise people either to take oral cyanocobalamin tablets 50–150 micrograms daily between meals or have a twice-yearly Hydroxocobalamin 1 mg injection.
In vegans, treatment may need to be life-long, whereas in other people with dietary deficiency replacement treatment can be stopped once the vitamin B12 levels have been corrected and the diet has improved.
BSH advice during COVID outbreak:
As these patients are B12 replete, B12 supplements can be suspended during the outbreak.
This group of patients can also be offered oral B12 50 mcg daily between meals if needed.
We suggest measuring serum B12 level before restarting injected B12 replacement again after the outbreak.
Give dietary advice about foods that are a good source of vitamin B12: Good sources of vitamin B12 include Eggs, meat, milk and other dairy products and fish (salmon and cod). Foods which have been fortified with vitamin B12 (for example some soy products, and some breakfast cereals and breads) are good alternative sources.