Availability of antidotes at acute care hospitals in Ontario

To the editor,

The study by Juurlink et al (1) that surveyed the availability of some antidotes found that most acute care hospitals in the province of Ontario did not stock adequate amount. This is the second study that finds this worrying situation in Canada. We have previously shown that the availability of 13 antidotes was also poor in the province of Quebec (more stringent criteria were used to defined adequate stocking) (table 1) (2). However, correcting the situation is probably not as expansive as it appears to be. Using antidote consumption obtained with the same survey, we have shown in another study that correcting the situation at the provincial level would only cost an increase of antidote inventory of 6 to 18% (3). This is explained by gross overstocking of some antidotes by some hospitals as noticed by Juurlink et al (1). Because our recommended minimal stock of 18 antidotes was based on level of hospital care, we think that the burden of keeping adequate antidote inventory should not be a problem even for smaller hospitals with limited pharmacy budget (cost in 2000: primary care hospitals, $4697; secondary, $7450; tertiary, $14273). Our recommended minimal stock aimed at providing adequate amount of antidote to treat a 70-Kg adult for 12 hours in primary and secondary hospitals and 24 hours in tertiary hospitals (3). As most antidotes are used infrequently – antidote inventory turnover of 0,3 to 7,4 compared with an average of 8,9 for all medications in Canadian pharmacies (3), the cost of maintaining an appropriate stock should also not be a concern with appropriate antidote usage considering that most antidotes can be credited if unused (100% for ethanol, deferoxamine, flumazenil, glucagon, methylene blue, nalaxone; 95% for digoxine immune FAB; and 90% n-acetylcysteine, pralidoxime, and pyridoxine).

References

1. Juurlink DN, McGuigan MA, Paton TW, Redelmeier DA. Availability of antidotes at acute care hospitals in Ontario. CMAJ 2001; 165: 27-30.

2. Bailey B, Bussières JF. Antidote availability in Quebec hospital pharmacies: Impact of N-acetylcysteine and naloxone comsumption. Can J Clin Pharmacol 2000; 7: 198-204.

3. Bussières JF, Bailey B. Insufficient stocking of antidotes in hospital pharmacies: Problem, causes, and solution. Can J Hosp Pharm 2000; 53: 325-37.

Benoit Bailey
Divisions of Emergency Medicine
and of Clinical Pharmacology and Toxicology
Department of Paediatrics
Hôpital Ste-Justine
Université de Montréal
Montréal, Qc

Jean-François Bussières
Department of Pharmacy
Hôpital Ste-Justine
Faculty of Pharmacy
Université de Montréal
Montréal, Qc

Table Availability of antidotes in Ontario and Quebec

% of hospitals with adequate amount of antidote*
Quebec (2) Ontario (1)

N-acetylcysteine 88 N/A
Ethanol 52 62
Cyanide antidote 16 18
Deferoxamine 25 55
Digoxin immune FAB 9 9
Dimercaprol 1 N/A
Flumazenil 47 92
Glucagon 0 32
Methylene blue 17 74
Naloxone 46 N/A
Physostigmine 17 N/A
Pralidoxime 9 27
Pyridoxine 0 23
Syrup of Ipecac N/A 88

*Using different criteria (Quebec: stock necessary to treat one 70 Kg adult for 24 hours and Ontario: stock to start treatment in one 70 Kg adult)
N/A: not available