According to NICE Clinical Knowledge Summaries and the British National Formulary , the standard treatment is intramuscular injections of 1,000 mcg (1 mg) hydroxocobalamin
Check for drug interactions - Some prescriptions, like proton pump inhibitors, can impact B12 absorption and may need to be changed
Q.LiuH.YangM.et al (2015)
Gently swirl the vial until the powder dissolves completely, usually 1 to 2 minutes
the form of a pre-dissolved solution in an applicator does not constitute a suggestion of injectable administration in humans
The 2 mL volume produces concentrations (2.5, 5, 10, 15 mg/mL) that put common doses on multiples of 10 units