Cyanide Toxicity

Treat empirically when a credible acute exposure is followed by severe neurologic dysfunction, respiratory failure, shock, cardiac arrest, or rapidly progressive metabolic acidosis. High-risk settings include enclosed-space fire smoke, known industrial or intentional cyanide exposure, and excessive or prolonged sodium nitroprusside infusion. Cyanide inhibits cytochrome oxidase, producing cellular oxygen-utilization failure despite oxygen delivery. ScienceDirect+2ScienceDirectCyanide Poisoning - an overview | ScienceDirect Topicsjournal chestnetAdult Toxicology in Critical Carea - CHEST JournalPubMedSodium thiosulfate or hydroxocobalamin for the empiric treatment of cyanide poisoning? - PubMed

Send blood cyanide testing if it can be obtained without interrupting resuscitation, but do not await the result. Cyanide assays are technically difficult; results from body fluids other than packed red blood cells are difficult to interpret. Acute clinical management should therefore be driven by exposure history and physiologic deterioration. accessdata fda+1accessdata fda[PDF] Sodium Nitroprusside Injection - accessdata.fda.govCDC[PDF] Toxicological Profile for Cyanide, Draft for Public Comment

Begin concurrent airway, ventilatory, circulatory, and high-concentration oxygen support while the antidote is prepared. In a patient with strongly suspected cyanide toxicity, toxicology or poison-center consultation should guide subsequent dosing and monitoring but must not delay hydroxocobalamin administration. dailymed nlm nih+1dailymed nlm nihThese highlights do not include all the information needed to use the SODIUM THIOSULFATE INJECTION safely and effectively. See full prescribing information for SODIUM THIOSULFATE INJECTION. Sodium Thiosulfate Injection, USP Initial U.S. Approval: 1992PubMedCyanide Toxicity - StatPearls - NCBI Bookshelf

Obtain arterial or venous blood gas analysis with lactate early to document acid-base severity and trend response. In sodium nitroprusside-associated toxicity, lactic acidosis and venous hyperoxemia are supportive findings, but neither reliably excludes dangerous cyanide burden early because acidosis may appear more than an hour after red-cell cyanide buffering capacity is exhausted. accessdata fdaaccessdata fda[PDF] Sodium Nitroprusside Injection - accessdata.fda.gov

In smoke exposure, order co-oximetry rather than relying on conventional pulse oximetry to assess carbon monoxide exposure. A carboxyhemoglobin concentration above 5% in nonsmokers or above 10% in smokers meets CDC laboratory criteria for carbon monoxide exposure; smokers may have baseline values of 6% to 10%. CDCCDCCase Definitions for Chemical Poisoning

Interpret cyanide-related findings in context. An almond-like breath odor and cherry-red appearance are classically described but are not sufficient to rule cyanide toxicity in or out. The practical discriminator remains a compatible exposure plus otherwise unexplained CNS or cardiovascular failure and severe metabolic derangement. CDCCDC[PDF] Toxicological Profile for Cyanide, Draft for Public Comment

Administer hydroxocobalamin 5 g IV over 15 minutes to adults with suspected severe cyanide toxicity. If clinical signs persist or recur, a second 5 g IV dose may be given; published recommendations describe repeat dosing up to a total of 15 g, while other regulatory materials describe repeating the initial 5 g dose once. Wiley+3WileyReview article: Management of cyanide poisoning - OvidPubMedCyanide Toxicity - StatPearls - NCBI BookshelfPubMedResuscitating Through the Smoke: Novel Use of Cyanocobalamin in a Pediatric House Fire Victim - PMCema europa eu[PDF] Cyanokit, INN-hydroxocobalamin - European Medicines Agency

For children, use hydroxocobalamin 70 mg/kg IV, not exceeding 5 g per dose. Use the same clinical trigger as in adults: a compelling exposure with severe or evolving cardiopulmonary, neurologic, or metabolic toxicity warrants treatment before laboratory confirmation. PubMed+1PubMedResuscitating Through the Smoke: Novel Use of Cyanocobalamin in a Pediatric House Fire Victim - PMCema europa eu[PDF] Cyanokit, INN-hydroxocobalamin - European Medicines Agency

Hydroxocobalamin binds cyanide to form nontoxic cyanocobalamin and is favored for empiric smoke-inhalation treatment because it avoids deliberate methemoglobin formation. Reported adverse effects include hypertension, hypersensitivity manifestations, nausea, dizziness, rigors, and hot flushes; rare anaphylaxis has been described. There are no absolute contraindications when life-threatening cyanide poisoning is suspected. ScienceDirect+2ScienceDirectCyanide Poisoning - an overview | ScienceDirect TopicsPubMedHydroxocobalamin - StatPearls - NCBI BookshelfPubMedResuscitating Through the Smoke: Novel Use of Cyanocobalamin in a Pediatric House Fire Victim - PMC

In enclosed-space fires, cyanide poisoning must be considered because combustion smoke can contain hydrogen cyanide, while carbon monoxide frequently produces overlapping neurologic and cardiovascular manifestations. Obtain co-oximetry promptly, but do not require a carboxyhemoglobin threshold to treat a patient with a compelling cyanide syndrome. ScienceDirect+2ScienceDirectCyanide Poisoning - an overview | ScienceDirect TopicsCDCCase Definitions for Chemical PoisoningPubMedSodium thiosulfate or hydroxocobalamin for the empiric treatment of cyanide poisoning? - PubMed

A carboxyhemoglobin concentration above 5% in nonsmokers or above 10% in smokers supports carbon monoxide exposure, but the value does not exclude concurrent cyanide poisoning. Give oxygen and prioritize hydroxocobalamin when cyanide toxicity is clinically severe; this avoids the oxygen-delivery penalty of nitrite-induced methemoglobinemia. publications aap+2publications aapSodium Nitrite and Sodium Thiosulfate | Pediatric Care OnlineCDCCase Definitions for Chemical PoisoningPubMedSodium thiosulfate or hydroxocobalamin for the empiric treatment of cyanide poisoning? - PubMed

Do not use apparent oxygenation alone to reassure yourself. Cyanide toxicity impairs cellular oxygen utilization, and conventional oxygen-saturation measures do not establish adequate tissue oxygen use. Follow clinical perfusion, hemodynamics, ventilation, neurologic status, and serial acid-base data after resuscitation and antidote administration. accessdata fda+1accessdata fda[PDF] Sodium Nitroprusside Injection - accessdata.fda.govScienceDirectCyanide Poisoning - an overview | ScienceDirect Topics

Suspect cyanide toxicity in a patient receiving sodium nitroprusside who develops unexplained metabolic acidosis, venous hyperoxemia, or clinical deterioration. Cyanide measurement should not be awaited: dangerous cyanide levels can precede acidosis by more than an hour, and a reasonable clinical suspicion is sufficient to start treatment. accessdata fdaaccessdata fda[PDF] Sodium Nitroprusside Injection - accessdata.fda.gov

Immediately discontinue sodium nitroprusside and provide ventilatory and circulatory support. The nitroprusside label describes treatment with sodium nitrite to create methemoglobin followed by sodium thiosulfate, but this approach must be individualized when concomitant hypoxemia, anemia, or carbon monoxide exposure makes induced methemoglobinemia hazardous. accessdata fda+2accessdata fda[PDF] Sodium Nitroprusside Injection - accessdata.fda.govdailymed nlm nihThese highlights do not include all the information needed to use the SODIUM THIOSULFATE INJECTION safely and effectively. See full prescribing information for SODIUM THIOSULFATE INJECTION. Sodium Thiosulfate Injection, USP Initial U.S. Approval: 1992publications aapSodium Nitrite and Sodium Thiosulfate | Pediatric Care Online

Trend blood gas parameters and lactate after stopping the infusion and administering antidotal therapy, but do not use a transiently nonacidotic blood gas to exclude toxicity. Obtain toxicology support for antidote choice and for interpretation of cyanide and thiocyanate testing, which may not be rapidly actionable. accessdata fda+1accessdata fda[PDF] Sodium Nitroprusside Injection - accessdata.fda.govPubMedCyanide Toxicity - StatPearls - NCBI Bookshelf

Following antidote administration, reassess airway protection, ventilatory requirements, blood pressure, perfusion, mental status, and serial blood gas and lactate measurements. Persistent or recurrent signs of poisoning after the sodium nitrite/sodium thiosulfate regimen are an indication for repeat treatment at one-half of the original dose; hydroxocobalamin guidance permits an additional 5 g dose when needed. dailymed nlm nih+2dailymed nlm nihThese highlights do not include all the information needed to use the SODIUM THIOSULFATE INJECTION safely and effectively. See full prescribing information for SODIUM THIOSULFATE INJECTION. Sodium Thiosulfate Injection, USP Initial U.S. Approval: 1992PubMedCyanide Toxicity - StatPearls - NCBI BookshelfPubMedResuscitating Through the Smoke: Novel Use of Cyanocobalamin in a Pediatric House Fire Victim - PMC

Admit patients with severe presentations, ongoing respiratory failure, shock, cardiac arrest, or persistent metabolic derangement to an intensive-care setting for continued organ support and serial reassessment. For intentional ingestion, obtain psychiatric evaluation after physiologic stabilization. PubMedPubMedCyanide Toxicity - StatPearls - NCBI Bookshelf

Document the exposure setting, timing, antidote dose and infusion time, initial and serial blood gas results, lactate, and co-oximetry results in smoke exposures. This record supports toxicology consultation, identifies mixed poisoning, and permits later interpretation of confirmatory cyanide testing. accessdata fda+2accessdata fda[PDF] Sodium Nitroprusside Injection - accessdata.fda.govCDCCase Definitions for Chemical PoisoningPubMedCyanide Toxicity - StatPearls - NCBI Bookshelf