Cyanokit (hydroxocobalamin injection)

Cyanokit (hydroxocobalamin) is an antidote for cyanide toxicity. It is used to treat people with known or suspected cyanide poisoning. Cyanide is an extremely toxic poison that can kill within minutes by preventing cells from using oxygen.

Common side effects of Cyanokit include:

• red-colored urine (chromaturia),
• skin redness,
• rash,
• nausea,
• headache,
• decreased white blood cells,
• infusion site reactions.

Other side effects of Cyanokit include:

• eye swelling/irritation/redness,
• difficulty swallowing,
• abdominal discomfort,
• vomiting,
• diarrhea,
• indigestion,
• swelling of extremities,
• chest discomfort,
• allergic reaction,
• memory impairment,
• dizziness,
• restlessness,
• shortness of breath,
• throat tightness and dry throat,
• itching,
• hot flush,
• increased sun sensitivity (photosensitivity).

Serious side effects of Cyanokit include:

• serious allergic reactions,
• high blood pressure,
• abnormal heartbeats.

Cyanokit drug interaction studies have not been conducted.

Cyanokit has not been adequately studied in pregnant women. It is unknown if Cyanokit is secreted in breast milk. Cyanokit may be given to nursing mothers in life-threatening situations. Breastfeeding should be stopped after receiving Cyanokit.

What are the important side effects of Cyanokit (hydroxocobalamin)?

• Red colored urine (chromaturia)
• Erythema
• Rash
• Nausea
• Headache
• Decreased white blood cells
• Infusion site reactions

Other side effects include:

• Eye swelling, irritation, redness
• Difficulty swallowing (dysphagia)
• Abdominal discomfort
• Vomiting
• Diarrhea
• Indigestion (dyspepsia)
• Peripheral edema
• Chest discomfort
• Allergic reaction
• Memory impairment
• Dizziness
• Restlessness
• Shortness of breath (dyspnea)
• Throat tightness and dry throat
• Itching
• Hot flush
• Increased sun sensitivity (photosensitivity)
• Possible serious side effects include:
• Serious allergic reactions
• High blood pressure
• Abnormal heartbeats

Cyanokit (hydroxocobalamin) side effects list for healthcare professionals

Serious adverse reactions with hydroxocobalamin include allergic reactions and increases in blood pressure.

Clinical Studies Experience

Because clinical trials were conducted under widely varying conditions, adverse reaction rates observed may not reflect the rates observed in practice.

Experience in Healthy Subjects

A double-blind, randomized, placebo-controlled, single-ascending dose (2.5, 5, 7.5, and 10 g) study was conducted to assess the safety, tolerability, and pharmacokinetics of hydroxocobalamin in 136 healthy adult subjects.

Because of the dark red color of hydroxocobalamin, the two most frequently occurring adverse reactions were chromaturia (red-colored urine) reported in all subjects receiving a 5 g dose or greater, and erythema (skin redness) which occurred in most subjects receiving a 5 g dose or greater.

Adverse reactions reported in at least 5% of the 5 g dose group and corresponding rates in the 10 g and placebo groups are shown in Table 3.

Table 3 Incidence of Adverse Reactions Occurring in > 5% of Subjects in 5 g Dose Group and Corresponding Incidence in 10 g Dose Group and Placebo

In this study, the following adverse reactions were reported to have occurred in a dose-dependent fashion and with greater frequency than observed in placebo-treated cohorts:

• increased blood pressure (particularly diastolic blood pressure),
• rash,
• nausea,
• headache,
• infusion site reactions.

All were mild to moderate in severity and resolved spontaneously when the infusion was terminated or with standard supportive therapies.

Other adverse reactions reported in this study and considered clinically relevant were:

• Eye disorders: swelling, irritation, redness
• Gastrointestinal disorders: dysphagia, abdominal discomfort, vomiting, diarrhea, dyspepsia, hematochezia
• General disorders and administration site conditions: peripheral edema, chest discomfort
• Immune system disorders: allergic reaction
• Nervous system disorders: memory impairment, dizziness
• Psychiatric disorders: restlessness
• Respiratory, thoracic and mediastinal disorders: dyspnea, throat tightness, dry throat
• Skin and subcutaneous tissue disorders: urticaria, pruritus
• Vascular disorders: hot flush

Experience in Known or Suspected Cyanide Poisoning Victims

Four open-label, uncontrolled clinical studies (one prospective and three retrospective) were conducted in known or suspected cyanide-poisoning victims. A total of 245 patients received hydroxocobalamin treatment in these studies.

Systematic collection of adverse events was not done in all of these studies, and interpretation of causality is limited due to the lack of a control group and circumstances of administration (e.g., use in fire victims). Adverse reactions reported in these studies listed by system organ class included:

• Cardiac disorders: ventricular extrasystoles
• Investigations: electrocardiogram repolarization abnormality, increased heart rate
• Respiratory, thoracic, and mediastinal disorders: pleural effusion

Adverse reactions common to both the studies in known or suspected cyanide poisoning victims and the study in healthy volunteers are listed in the healthy volunteer section only and are not duplicated in this list.

What drugs interact with Cyanokit (hydroxocobalamin)?

No formal drug interaction studies have been conducted with Cyanokit.

Summary

Cyanokit (hydroxocobalamin) is an antidote for cyanide toxicity. It is used to treat people with known or suspected cyanide poisoning. Common side effects of Cyanokit include red colored urine (chromaturia), skin redness, rash, nausea, headache, decreased white blood cells, and infusion site reactions. Cyanokit has not been adequately studied in pregnant women. It is unknown if Cyanokit is secreted in breast milk.