Reviewed on 6/24/2022

What Is Hydroxocobalamin and How Does It Work?

Hydroxocobalamin is a prescription medication used to treat the symptoms of Cyanide Poisoning and Vitamin B12 Deficiency. 

  • Hydroxocobalamin is available under the following different brand names: Cyanokit

What Are Side Effects Associated with Using Hydroxocobalamin?

Common side effects of Hydroxocobalamin include:

  • nausea,
  • headache,
  • acne,
  • skin rash,
  • redness of the skin,
  • the red coloring of the urine (may last 2 to 5 weeks), and
  • pain, swelling, or irritation at the injection site

Serious side effects of Hydroxocobalamin include:

  • hives,
  • difficulty breathing,
  • swelling of the face, lips, tongue, or throat,
  • chest tightness,
  • acne-like skin rash,
  • bright red blood in the stools,
  • chest pain,
  • fast or uneven heart rate,
  • severe shortness of breath,
  • wheezing,
  • gasping for breath,
  • cough with foamy mucus,
  • swelling in the feet or ankles,
  • light-headedness,
  • severe headache,
  • blurred vision,
  • buzzing in the ears,
  • anxiety,
  • confusion,
  • chest pain,
  • shortness of breath,
  • uneven heartbeats, and
  • seizures

Rare side effects of Hydroxocobalamin include:

  • none 

This is not a complete list of side effects and other serious side effects or health problems that may occur as a result of the use of this drug. Call your doctor for medical advice about serious side effects or adverse reactions. You may report side effects or health problems to FDA at 1-800-FDA-1088.

What Are Dosages of Hydroxocobalamin?

 Adult and pediatric dosage

  • Lyophilized powder for reconstitution
  • 5g/vial
  • Injection solution
  • 1000mcg/mL (30mL)
  • Cyanide Poisoning
  • Adult dosage
  • 70 mg/kg (usually 5 g) intravenous infusion over 15 minutes; an additional 5 g intravenous may be given depending on the severity of poisoning and clinical response  
  • Not to exceed a cumulative dose of 10 g
  • Vitamin B12 Deficiency
  • Adult dosage
  • Initial: 30 mcg Intramuscular once a day for 5-10 days
  • Maintenance: 100-200 mcg Intramuscular every month; may administer higher dose if critically ill or hyperthyroidism or neurologic or infectious disease present
  • Pediatric dosage
  • Initial: 100 mcg Intramuscular once a day for above 2 weeks (1-5 mg total dose)
  • Maintenance: 30-50 mcg Intramuscular every month

Dosage Considerations – Should be Given as Follows

  • See “Dosages”

What Other Drugs Interact with Hydroxocobalamin?

If your medical doctor is using this medicine to treat your pain, your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them. Do not start, stop, or change the dosage of any medicine before checking with your doctor, health care provider, or pharmacist first

  • Hydroxocobalamin has no noted severe interactions with any other drugs.
  • Hydroxocobalamin has no noted serious interactions with any other drugs.
  • Hydroxocobalamin has no noted moderate interactions with any other drugs.
  • Hydroxocobalamin has no noted minor interactions with any other drugs.

This information does not contain all possible interactions or adverse effects. Visit the RxList Drug Interaction Checker for any drug interactions. Therefore, before using this product, tell your doctor or pharmacist about all your products. Keep a list of all your medications with you and share this information with your doctor and pharmacist. Check with your health care professional or doctor for additional medical advice, or if you have health questions or concerns.

What Are Warnings and Precautions for Hydroxocobalamin?


  • None listed by the manufacturer 

Effects of drug abuse

  • None

Short-Term Effects

  • See “What Are Side Effects Associated with Using Hydroxocobalamin?”

Long-Term Effects

  • See “What Are Side Effects Associated with Using Hydroxocobalamin?”


  • Consider alternative therapies, if available, in patients with known anaphylactic reactions to hydroxocobalamin or cyanocobalamin
  • Acute renal failure with acute tubular necrosis, renal impairment, and urine calcium oxalate crystals have been reported following therapy; monitor renal function for 7 days following therapy
  • Substantial increases in blood pressure may occur following therapy; monitor blood pressure during treatment

Pregnancy and Lactation

  • Available data from cases reported in published literature and postmarketing surveillance in pregnant women are insufficient to identify a drug-associated risk for major birth defects, miscarriage, or adverse maternal and fetal outcomes
  • There are risks to pregnant women and fetuses associated with untreated cyanide poisoning
  • Cyanide readily crosses the placenta; cyanide poisoning is a medical emergency in pregnancy that can be fatal for pregnant women and fetuses if left untreated; life-sustaining therapy should not be withheld due to pregnancy


  • Breastfeeding is not recommended during treatment; there are no data to determine when breastfeeding may be safely restarted following administration of the drug; hydroxocobalamin and Vitamin B12 (which is formed when hydroxocobalamin combines with cyanide) are present in human milk; there are no data on effects of hydroxocobalamin on breastfed infant or effects on milk production

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