RUBIVITE
Clinical safety rating: caution
Comprehensive clinical and safety monograph for RUBIVITE (RUBIVITE).
Hydroxocobalamin is a synthetic form of vitamin B12 that acts as a cofactor for methionine synthase and methylmalonyl-CoA mutase, essential for DNA synthesis, erythrocyte maturation, and neurological function. In cyanide poisoning, it binds cyanide ions to form nontoxic cyanocobalamin, which is excreted renally.
| Metabolism | Hydroxocobalamin is not metabolized; it is converted to active coenzyme forms (methylcobalamin, adenosylcobalamin) intracellularly. In cyanide poisoning, hydroxocobalamin binds cyanide to form cyanocobalamin, which is excreted in urine. |
| Excretion | Primarily renal; ~50-80% of absorbed dose excreted unchanged in urine within 24 hours; biliary/fecal excretion accounts for minor fraction (<10%) |
| Half-life | Terminal elimination half-life is approximately 6-8 hours in patients with normal renal function; prolonged in renal impairment (up to 24-48 hours in severe impairment) |
| Protein binding | Moderate binding to transcobalamin II; approximately 30-40% bound |
| Volume of Distribution | Approximately 0.5-1.0 L/kg; distributes into all tissues, with highest concentrations in liver, kidney, and bone marrow |
| Bioavailability | Oral: <1% (with intrinsic factor); without intrinsic factor, negligible absorption; Sublingual: ~1-2%; Intramuscular: 100% |
| Onset of Action | Oral: 1-2 hours; Sublingual: 0.5-1 hour; Intramuscular: 0.5-1 hour; Subcutaneous: 0.5-1 hour |
| Duration of Action | Clinical effect duration is approximately 24-48 hours; sufficient for daily or alternate-day dosing in maintenance therapy |
1000 mcg intramuscularly or deep subcutaneous injection once daily for 5-7 days, then 100-1000 mcg monthly for maintenance.
| Dosage form | INJECTABLE |
| Renal impairment | No adjustment required for renal impairment; cyanocobalamin is not significantly renally eliminated. |
| Liver impairment | No adjustment required for hepatic impairment; metabolism is not primarily hepatic. |
| Pediatric use | Dosing based on age: Infants 0-6 months: 0.4 mcg/kg/day intramuscularly; Children 6 months to 10 years: 1 mcg/kg/day intramuscularly; Children >10 years: same as adult dosing. |
| Geriatric use | No specific adjustment; use standard adult dosing with monitoring for B12 levels and potential concurrent deficiencies. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for RUBIVITE (RUBIVITE).
| Breastfeeding | Components likely excreted in breast milk; considered compatible with breastfeeding at recommended doses. M/P ratio not established. |
| Teratogenic Risk | Rubivite is a formulation containing vitamins and minerals. At recommended doses, no teratogenic risk is established. Excessive vitamin A (if present) may be teratogenic in first trimester; specific product must be checked. |
| Fetal Monitoring |
■ FDA Black Box Warning
No FDA black box warning.
| Serious Effects |
["Hypersensitivity to hydroxocobalamin or any component","Leber's disease (hereditary optic nerve atrophy) – due to risk of optic atrophy with prolonged use"]
| Precautions | ["May cause anaphylactic reactions and angioedema","Interference with clinical lab tests (e.g., bilirubin, creatinine, hemoglobin) due to red discoloration of plasma/urine","Hypertension (transient increase in blood pressure)","Headache, nausea, injection site reactions","Not a substitute for dietary vitamin B12 in megaloblastic anemia without proper diagnostic evaluation"] |
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| Monitor maternal serum levels of vitamins (e.g., B12, folate, iron) if deficiency suspected. Fetal growth monitoring by ultrasound if prolonged high-dose use. |
| Fertility Effects | No known adverse effect on fertility; may improve fertility if correcting deficiencies. |