The reason for my post is that my written application to obtain 'Cyanokit'
has been rejected by our local pharmacy committee on the basis of cost and
'lack of evidence'.

Hence I was interested in the practice of other departments and remain
concerned re toxicity and efficacy of existing standard therapies.



John Black

-----Original Message-----
From: Anton van Dellen [mailto:[log in to unmask]]
Sent: 26 July 2003 15:38
To: [log in to unmask]
Subject: Re: Hydroxycobalamine for cyanide poisoning

BNF only refers to i/m administration, at dose of 1mg per admin. Quite
agree that maybe we should consider administering on spec. Most
published data relates to concomitant use of B12 with SNP.

Anton
Staffs

Crit Care Med. 1993 Mar;21(3):465-7.
Use of vitamin B12 in the treatment and prevention of
nitroprusside-induced cyanide toxicity.
Zerbe NF, Wagner BK.
Rutgers University/College of Pharmacy, Piscataway, NJ
OBJECTIVE: To review the mechanism of action, safety, and efficacy of
hydroxocobalamin in the treatment and prevention of
nitroprusside-induced cyanide toxicity. DATA SOURCES: English and
foreign-language journal articles and reference texts identified from
Index Medicus. Both animal and human studies were included. DATA
SYNTHESIS: High-dose or prolonged therapy with nitroprusside in patients
with hepatic or renal dysfunction increases the risk for
nitroprusside-induced cyanide or thiocyanate toxicity, respectively.
Hydroxocobalamin has been shown to significantly reduce RBC and plasma
cyanide concentrations in animals and surgical patients without
producing clinically important adverse effects or toxic metabolites.
Thiosulfate infusions also decrease cyanide toxicity but can cause
accumulation of thiocyanate resulting in clinical toxicity.
Cyanocobalamin cannot effectively remove cyanide due to poor binding.
CONCLUSIONS: Hydroxocobalamin is a safe and effective agent in the
prevention and treatment of nitroprusside-induced cyanide toxicity.
Prolonged or high-dose infusions of nitroprusside should be minimized in
critically ill patients, especially if hepatic and/or renal dysfunction
is present.

Anesthesiology. 1981 Apr;54(4):305-9.
Consumption of vitamin B12 during sodium nitroprusside administration in
humans.
Fahmy NR.
In view of evidence suggesting possible participation of cobalamin in
cyanide metabolism, the effects of sodium nitroprusside (SNP) infusion
on blood cyanide and plasma thiocyanate levels and serum vitamin B12
levels were examined in ten patients undergoing major orthopedic
procedures. Whole blood cyanide concentrations increased significantly
(P less than 0.001) from 3.6 +/- 1.1 to 65.7 +/- 16.2 micrograms/dl, and
total serum B12 values decreased significantly (P less than 0.005) from
482 +/- 56 to 267 +/- 42 pg/ml, three hours after SNP therapy. Plasma
thiocyanate did not change. Cyanide released from SNP converts
hydroxocobalamin to cyanocobalamin, which is readily excreted in urine.
These variables were not changed in six patients (control) who received
trimethaphan. In vitro experiments revealed that none of the serum
factor(s) nor nitroprusside interfered with the assay of B12.
Hydroxocobalamin may be an appropriate adjunct during SNP therapy.
Vic Calland wrote:
>
> I have heard about the use of B12 for cyanide poisoning but have no
> knowledge of dose, safety, adverse reactions and degree of benefit.
> Obviously though, if as safe as I am led to believe then should it not
> be given to anyone moribund from domestic smoke inhalation. Could
> someone educate me please?
>
> Vic Calland
>
> -----Original Message-----
> From: [log in to unmask]
> [mailto:[log in to unmask]] On Behalf Of BINCHY Dr J, A&E
> Consultant
> Sent: 25 July 2003 18:42
> To: [log in to unmask]
> Subject: Re: Hydroxycobalamine for cyanide poisoning
>
> We normally keep a box of it in Plymouth
>
> James
>
> -----Original Message-----
> From: Black, John [mailto:[log in to unmask]]
> Sent: 24 July 2003 10:43
> To: [log in to unmask]
> Subject: Hydroxycobalamine for cyanide poisoning
>
> Dear colleagues,
>
> I would be interested to know whether any Emergency Departments are
> keeping
> a limited supply of hydroxycobalamine for use in unconscious house fire
> victims.
>
> John Black
> Oxford.