New formulation of Oral Rehydration Salts (ORS) with reduced osmolarity-February 2004
“New ORS” Q&A
Why has a “New” Oral Rehydration Salts (ORS) formula been developed?
Why “reduced osmolarity”?
Is diarrhoea really that much of a problem for children?
When will the new ORS be available?
What do I do with the old ORS solution? Should I discard it and only use the new low osmolarity ORS solution?
What about local production of the new ORS?
How should the new ORS solution be given?
Is there any risk associated with the use of this new ORS?
What is the cost of the new ORS?
1. Why has a “New” Oral Rehydration Salts (ORS) formula been developed?
Two decades ago, diarrhoea was responsible for about 5 million deaths
annually. Through programs that distribute and promote ORS and home
treatments for dehydration as well as preventive interventions, deaths
have decreased to about 2 million. In spite of this success, there remains
criticism from health workers and mothers that the original ORS solution
did not stop diarrhoea or reduce the duration of the episode. This is why,
during the past 20 years, research has been undertaken to develop an
“improved” ORS that would be safe and effective for treating or preventing
dehydration in all types of diarrhoea, and would also have other clinical
benefits when compared with standard ORS.
The study results clearly describe the advantages of this new reduced
osmolarity ORS solution in treating children with acute diarrhoea:
It reduces stool output or stool volume by about 25% when compared to the
original WHO-UNICEF ORS solution,
It reduces vomiting by almost 30%,
It reduces the need for unscheduled IV therapy by more than 30%.
This last advantage is particularly important because this means less
hospitalisation, and therefore less risk of hospital acquired infections,
less disruption of breastfeeding, decreased use of needles (which remains
a strong advantage especially in high HIV prevalence contexts), less cost,
and in areas where IV therapy is not readily available less risk of dying
2. Why “reduced osmolarity”?
Studies have shown that the efficacy of ORS for treatment of children with
acute 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. This compares to the original solution which contained 90 mEq/l of
sodium with a total osmolarity of 311 mOsm/l. There has been a concern
that the original solution, which is slightly “hyperosmolar” when compared
with plasma, may risk hypernatraemia (high plasma sodium concentration) or
an increase in stool output, especially in infants and young children.
3. Is diarrhoea really that much of a problem for children?
The recently published “Lancet Series” on child survival estimates that
there are almost 11 million deaths occurring each year in children under
the age of five. The vast majority of these deaths occur in low income and
least developed countries, particularly those in South Asia and Africa.
Although use of ORS or increased fluids, use of clean water and improved
hygiene, and increased breastfeeding practices have contributed
substantially to a dramatic global reduction in mortality from diarrhoeal
disease, there are still approximately 2 million deaths each year as a
result of diarrhoea. The Lancet papers also estimate that use of Oral
Rehydration Therapy by itself could prevent more than 5% of under-five
deaths that occur, and therefore its wide availability and proper use is a
key to improved child survival.
4. When will the new ORS be available?
Supply Division normally keeps 1-2 months stock of ORS in the warehouse in
Copenhagen, and it is suggested that there should be an overlap of the two
formulations for a period of about two months. The new ORS was made
available from UNICEF Supply Division in February 2004.
The shelf-life of the product is 3 years, without any particular storage
precautions. Because there is less sodium and glucose in the new product,
the package will be made a bit smaller later in 2004, however the initial
supplies have identical package size as compared to the old ORS. The new
product will be clearly labelled as “New Formula” with an expiration date
5. What do I do with the old ORS solution? Should I discard it and only
use the new low osmolarity ORS solution?
You should not hesitate to continue using the standard WHO UNICEF ORS (90
mEq/l of sodium with a total osmolarity of 311 mOsm/l solution), which is
highly effective in the treatment of dehydration. However, because of its
added advantages, WHO and UNICEF now recommend that countries use and
manufacture reduced osmolarity ORS.
Countries should take this opportunity to review amounts of existing
stocks of ORS. If any outdated stocks are found, these should be
discarded. Any existing stocks that have not reached their expiry date
should be used up first, on a “First In –First Out” basis.
6. What about local production of the new ORS?
For local production, the manufacture of the new reduced osmolarity ORS
can normally be undertaken without any change in equipment or new
investment in factories where the standard WHO UNICEF ORS has been
produced previously. UNICEF has, in the past, had a large input into
establishing local manufacturing of ORS, however these activities are no
longer routinely undertaken or supported from central level. Despite this,
"local manufacturers" of ORS need to be informed of the new formulation.
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:
|should at least equal that of sodium but
should not exceed 111 mmol/l
|should be within the range of 60-90 mEq/l
|should be within the range of 15-25 mEq/l
|should be within the range of 8-12 mmol/l
|should be within the range of 50-80 mEq/l
7. How should the new ORS solution be given?
The new ORS is to be mixed and given in the same manner as the original
solution. The new ORS packet is still to be mixed in 1 litre of clean
water. A family member should be taught to prepare and give ORS solution.
The solution should be given to infants and young children using a clean
spoon or cup. Feeding bottles should not be used. For babies, a dropper or
syringe (without the needle) can be used to put small amounts of solution
into the mouth. Children under 2 years of age should be offered a
teaspoonful every 1-2 minutes; older children (and adults) may take
frequent sips directly from the cup. Remember that breastfeeding should be
continued for infants and young children.
8. Is there any risk associated with the use of this new ORS?
Some studies have reported a slightly increased risk of hyponatraemia (low
plasma sodium concentration) in patients who have received this new ORS
solution. However, this decrease, which was very limited, was not
associated with any clinical signs. WHO is planning to monitor this very
carefully by doing what we call “post-marketing” studies: in areas where
the new ORS will first be introduced, they will monitor the
incidence/prevalence of hyponatraemia, biochemically as well as
9. What is the cost of the new ORS?
Because of the reduced amount of sodium and glucose, and smaller
packaging, the new ORS solution will cost slightly less than that which
was previously used (by about 15%).
UNICEF country programmes should advocate for free distribution of the ORS
for children whenever possible, in order to increase the availability and
accessibility for the poorest and those most at risk.