E-drug: New ORS formulation
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WHO / UNICEF
ORAL REHYDRATION SALTS (ORS)
A NEW REDUCED OSMOLARITY FORMULATION
For more than 25 years WHO and UNICEF have recommended a single
formulation of glucose-based Oral Rehydration Salts (ORS) to prevent
or treat dehydration from diarrhoea irrespective of the cause or age
group affected. This product, which provides a solution containing
90 mEq/l of sodium with a total osmolarity of 311 mOsm/l, has proven
effective and without apparent adverse effects in worldwide use. It
has contributed substantially to the dramatic global reduction in
mortality from diarrhoeal disease during the period.
For the past 20 years, numerous studies have been undertaken to
develop an "improved" ORS. The goal was a product that would be at
least as safe and effective as standard ORS for preventing or
treating dehydration from all types of diarrhoea but which, in
addition would reduce stool output or have other important clinical
benefits. One approach has consisted in reducing the osmolarity of
ORS solution to avoid possible adverse effects of hypertonicity on
net fluid absorption. This was done by reducing the solution's
glucose and salt (NaCl) concentrations.
Studies to evaluate this approach were reviewed at a consultative
technical meeting held in New York (USA) in July 2001 1,and technical
recommendations were made to WHO and UNICEF on the efficacy and
safety of reduced osmolarity ORS in children with acute non-cholera
diarrhoea, and in adults and children with cholera.
These studies showed that the efficacy of ORS solution for treatment
of children with acute non-cholera diarrhoea is improved by reducing
its sodium concentration to 75 mEq/l, its glucose concentration to 75
mmol/l, and its total osmolarity to 245 mOsm/l. The need for
unscheduled supplemental IV therapy in children given this solution
was reduced by 33%. In a combined analysis of this study and studies
with other reduced osmolarity ORS solutions (osmolarity 210-268
mOsm/l, sodium 50-75 mEq/l) stool output was also reduced by about
20% and the incidence of vomiting by about 30%. !. The 245 mOsm/l
solution also appeared to be as safe and at least as effective as
standard ORS for us in children with cholera.
The reduced osmolarity ORS containing 75 mEq/l sodium, 75 mmol/l
glucose (total osmolarity of 245 mOsm/l) is as effective as standard
ORS in adults with cholera. However, it is associated with an
increased incidence of transient, asymptomatic hyponatraemia. This
reduced osmolarity ORS may be used in place of standard ORS for
treating adults with cholera, but careful monitoring is advised to
better assess the risk, if any, of symptomatic hyponatraemia.
Because of the improved effectiveness of reduced osmolarity ORS
solution, especially for children with acute, non-cholera diarrhoea,
WHO and UNICEF now recommend that countries use and manufacture the
following formulation in place of the previously recommended ORS
solution with a total osmolarity of 311 mOsm/l.
Reduced osmolarity
ORS grams/litre
Sodium chloride 2.6
Glucose, anhydrous 13.5
Potassium chloride 1.5
Trisodium citrate, dihydrate 2.9
Reduced osmolarity ORS mmol/litre
Sodium 75
Potassium 20
Chloride 65
Glucose 75
Citrate 10
Total osmolarity 245
Although this single ORS formulation is recommended, WHO and UNICEF
have previously published criteria, which remain unchanged, for
acceptable ORS formulations. These criteria are listed below; they
specify the desired characteristics of the solution after it has been
prepared according to the instructions on the packet:
The total substance concentration (including that contributed by glucose)
should be within the range of 200-310 mmol/l
The individual substance concentration
Glucose should at least equal that of sodium but
should not exceed 111 mmol/l
Sodium should be within the range of 60-90 mEq/l
Potassium should be within the range of 15-25 mEq/l
Citrate should be within the range of 8-12 mmol/l
Chloride should be within the range of 50-80 mEq/l
1 Reduced osmolarity oral rehydration salts (ORS) formulation -
Report from a meeting of experts jointly organized by UNICEF and
WHO.WHO/CAH/01.22
http://www.who.int/child-adolescent-health/New_Publications/CHILD_HEALTH/Exp
ert_consultation.htm
[Don't forget to check the URL for wrapping. BS]
--
Beverley Snell
Centre for International Health
Macfarlane Burnet Institute for Medical Research & Public Health
Telephone 613 9282 2115 / 9282 2275
Fax 613 9482 3123
Time zone: 10 hours ahead of GMT.
email <bev@burnet.edu.au>
Please note that our postal address from 20 June will be:
GPO Box 2284, Melbourne 3001 Australia
Our site address will be:
Alfred Medical Research & Education Precinct (AMREP),
corner Punt & Commercial Roads, Prahran 3181
Fax 61 3 9282 2144
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