Hydroxocobalamin (B12) Injection Solution

Hydroxocobalamin (B12) Injection Solution

Available presentation(s): 5 mL. Verify the exact concentration and total active quantity on the prescription and dispensing label.

Introduction: Hydroxocobalamin is a form of vitamin B12 used parenterally for B12 deficiency; much larger antidotal doses are used for cyanide poisoning in separate approved products. These indications and dosing schemes are not interchangeable.

Dosage: For B12 deficiency, dosing depends on cause, severity, neurological involvement and maintenance needs; follow NZF/local guidance and the prescription. The listed 1 mg/mL, 5 mL presentation must not be used as a cyanide-antidote substitute. Confirm route and schedule.

Mechanisms of Action: Converted to active cobalamin cofactors required for methionine synthase and methylmalonyl-CoA mutase. In cyanide poisoning, high-dose hydroxocobalamin binds cyanide to form cyanocobalamin.

Contraindications & Precautions: Avoid in hypersensitivity to cobalamins/cobalt. Hypokalaemia can occur early during treatment of severe megaloblastic anaemia; monitor when indicated. Diagnostic blood samples should ideally be obtained before therapy.

Interactions: Chloramphenicol may blunt haematologic response. Metformin, proton-pump inhibitors and nitrous oxide can affect B12 status or function. High-dose antidotal products interfere with laboratory tests and dialysis detectors; this is less relevant to nutritional dosing.

Adverse Reactions / Side Effects: Injection-site pain, rash, pruritus, diarrhoea, headache and transient hypertension may occur; anaphylaxis is rare. Acneiform eruptions have been reported.

Pregnancy & Breastfeeding: Treat confirmed deficiency during pregnancy and breastfeeding because untreated deficiency can harm parent and infant. Use the clinically indicated replacement dose.

Storage: Store under the conditions stated on the Optimus dispensing label and product-specific worksheet. Protect from light where labelled. Do not freeze unless explicitly validated. Maintain cold chain if the label requires refrigeration. Do not use after the assigned beyond-use date or if there is visible particulate matter, precipitation, colour change, loss of container integrity or evidence of improper storage. Once entered, follow the validated in-use time; do not assume a compounded vial is multi-dose.

References

• New Zealand Formulary (NZF), current online edition; product-specific approved data sheets where available; USP Pharmaceutical Compounding—Sterile Preparations; and Optimus Healthcare validated formulation, sterility/endotoxin controls and assigned beyond-use date.
• DailyMed. Thiamine Hydrochloride, Pyridoxine Hydrochloride, Hydroxocobalamin and Levocarnitine injection labels, current editions. https://dailymed.nlm.nih.gov/
• NIH Office of Dietary Supplements. Health Professional Fact Sheets (vitamins and minerals), current online editions. https://ods.od.nih.gov/factsheets/list-VitaminsMinerals/