What is hydroxocobalamin?

Hydroxocobalamin is a form of vitamin B-12. It is used as an antidote to cyanide poisoning. Hydroxocobalamin works by helping cells in the body convert cyanide to a form that can be removed from the body through urination.

Hydroxocobalamin is used in an emergency to treat cyanide poisoning. This type of poisoning can occur if you are exposed to smoke from a house or industrial fire, if you swallow or breathe in cyanide, or if you get cyanide on your skin.

Hydroxocobalamin may also be used for purposes other than those listed in this medication guide.


Hydroxocobalamin is usually given in an emergency, so you may not have time to tell your caregivers about any medical conditions you have. However, you will need follow-up medical care after receiving this medication. Tell your doctor if you have:

  • high blood pressure;
  • heart disease; or
  • congestive heart failure.

FDA pregnancy category C. This medication may be harmful to an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant during treatment.

It is not known whether hydroxocobalamin passes into breast milk or if it could harm a nursing baby. Do not use this medication without telling your doctor if you are breast-feeding a baby.

If your skin turns red after receiving this medication, avoid exposure to sunlight or artificial UV rays (sunlamps or tanning beds). Hydroxocobalamin can make your skin more sensitive to sunlight and sunburn may result. Use a sunscreen (minimum SPF 15) and wear protective clothing if you must be out in the sun.

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An overdose of hydroxocobalamin is extremely unlikely.

Since hydroxocobalamin is used in an emergency, you will most likely be given only one or two doses of this medication.

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Side effects

Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

Call your doctor at once if you have any of these serious side effects:

  • increased blood pressure (severe headache, blurred vision, trouble concentrating, chest pain, numbness, seizure);
  • fast or uneven heart rate;
  • bright red blood in your stools; or
  • swelling in your hands or feet.

Less serious side effects are more likely to occur, such as:

  • red coloring of your skin or urine (this may last up to 2 weeks);
  • nausea, vomiting, diarrhea, stomach pain;
  • acne, skin rash or itching;
  • warmth or redness under your skin;
  • dry throat, trouble swallowing;
  • headache, dizziness, memory problems, restless feeling;
  • pain, swelling, or irritation of your skin where the injection was given; or
  • eye redness or irritation.

Side effects other than those listed here may also occur. Talk to your doctor about any side effect that seems unusual or that is especially bothersome. You may report side effects to FDA at 1-800-FDA-1088.

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Hydroxocobalamin is usually given in an emergency, so you may not have time to tell your caregivers about any other medications you are using. However, you will need follow-up medical care after receiving hydroxocobalamin. Tell your doctor about all the prescription and over-the-counter medications you use. This includes vitamins, minerals, herbal products, and drugs prescribed by other doctors. Do not start using a new medication without telling your doctor if you have recently be treated with hydroxocobalamin.

Other Names

Cobalin-H, Cyanokit, Hydro-Cobex, Hydroxocobalamin, Hydroxy-Cobal, Neo-Cytamen, and hydroxocobalamin

Available Strengths & Dosages

Route Form Strength
injectable solution 1000 mcg/mL
compounding powder -

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Every effort has been made to ensure that the information provided by Cerner Multum, Inc. ('Multum') is accurate, up-to-date, and complete, but no guarantee is made to that effect. Drug information contained herein may be time sensitive. Multum information has been compiled for use by healthcare practitioners and consumers in the United States and therefore Multum does not warrant that uses outside of the United States are appropriate, unless specifically indicated otherwise. Multum's drug information does not endorse drugs, diagnose patients or recommend therapy. Multum's drug information is an informational resource designed to assist licensed healthcare practitioners in caring for their patients and/or to serve consumers viewing this service as a supplement to, and not a substitute for, the expertise, skill, knowledge and judgment of healthcare practitioners. The absence of a warning for a given drug or drug combination in no way should be construed to indicate that the drug or drug combination is safe, effective or appropriate for any given patient. Multum does not assume any responsibility for any aspect of healthcare administered with the aid of information Multum provides. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the drugs you are taking, check with your doctor, nurse or pharmacist.

Copyright 1996-2004 Cerner Multum, Inc. Version 2.05. Revision date 8/23/04

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