Combined antidotal and hemodialysis treatments for nitroprusside-induced cyanide toxicity

Dialysis for Thiocyanate Intoxication: A Case Report and Review of the Literature

Limited data are available on the use of dialysis to treat cyanide or thiocyanate intoxication. This report describes the case of a 65-year-old woman with renal insufficiency who had development of thiocyanate toxicity secondary to a nitroprusside infusion. A rapid decline in her blood thiocyanate level was observed in response to initiation of continuous venovenous hemodiafiltration.

Cyanide toxicity from sodium nitroprusside: risks and management

OBJECTIVE

To review the risks, manifestations, and treatment of cyanide toxicity from nitroprusside therapy.

DATA SOURCES

All English case reports identified in Index Medicus (MEDLINE) of cyanide intoxication related to nitroprusside from 1970 to the present were reviewed. In addition, literature regarding the incidence, risks, and treatment of cyanide toxicity from nitroprusside is presented.

CONCLUSIONS

Numerous cases of cyanide toxicity associated with nitroprusside have been reported. The overall incidence appears to be infrequent; however, certain patients may be at high risk. Risk factors may include hypoalbuminemia, cardiopulmonary bypass procedures, or the administration of moderate to high doses of nitroprusside. Treatment of cyanide toxicity requires the cessation of nitroprusside and, for severe toxicity, use of the cyanide antidote kit. Cyanide toxicity from nitroprusside may be prevented by concomitant administration of sodium thiosulfate infusions.

Cyanide poisoning from metal cleaning solutions

We report two cases of cyanide poisoning from accidental ingestion of an imported metal cleaning solution used by some Southeast Asians for shining coins. Both patients received specific therapy and recovered completely after a dramatic sequence of sudden collapse and severe cardiovascular compromise.

Comparison of nitrite treatment and stroma-free methemoglobin solution as antidotes for cyanide poisoning in a rat model

The standard nitrite/thiosulfate regimen for cyanide poisoning was tested in our rat model. By modifying the treatment regimen and the nitrite solution an effective antidote against an LD90 of cyanide could be produced. However, this treatment was effective against two times the LD90 only when administered ten minutes prior to cyanide injection. These results are in marked contrast to our results with stroma-free methemoglobin solutions (SFMS) which showed SFMS to be a highly effective antidote against four times the LD90 when administered 30 seconds after an intravenous injection of cyanide. SFMS proved to be an effective antidote for two times the LD90 when administered up to sixty seconds after the cessation of respiration.

Stroma-free methemoglobin solution: an effective antidote for acute cyanide poisoning

Several aspects of stroma-free methemoglobin solution (SFMS) as a cyanide antidote were investigated using a rat model. Stroma-free methemoglobin solution was more than 90% effective against multiples of the LD90 of cyanide up to and including four times the LD90 and approximately 50% effective against multiples up to and including eight times the LD90. Highly concentrated solutions of SFMS (33 g/dl) did not differ significantly from less concentrated solutions of SFMS (16 g/dl) when compared on the basis of efficacy. Administration of large doses of SFMS alone resulted in no apparent morbidity or mortality. It could be that SFMS is a safe and effective alternative antidote for the treatment of cyanide poisoning.