Frequently Asked Questions : Phthalates In Medical Devices
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What types of medical products contain phthalate
plasticisers?
There are three main types of medical products containing
phthalates:
Containers: including flexible bags for
intravenous or nutritional fluids, solutions, drug and
anticoagulants. They are also used to collect and store blood and
plasma (IV blood bags) and to collect urine.
Flexible tubing: including blood circuit tubes,
infusers, catheters and endotracheal tubes.
Protective devices: including gloves and oxygen
tents.
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Why is Plasticised PVC preferred over other plastics or
materials?
Sterilisation: Plasticised PVC maintains its
high integrity under extreme hot and cold temperatures
Transparency: Plasticised PVC has exceptionally
good clarity so that the flow of liquids through tubes, for
example, can be carefully monitored.
Flexibility: It is highly resistant to
‘kinking’. Therefore it reduces the risk of
interruption to the flow of fluids in tubes.
Strength and resistance: It has the strength
and durability to resist tears, protecting both doctors and
patients at the same time as preventing the spread of infection and
germs.
Cost: Plasticised PVC is inexpensive. It allows
hospitals to use quality disposable items that help reduce
infection rates.
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What phthalates are used in the manufacture of medical
devices?
By far the most widely used is DEHP (di-2-ethylhexyl phthalate),
sometimes also known as DOP (di-octyl phthalate).
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Why is DEHP preferred to other phthalates?
Every phthalate offers slightly different properties. DEHP is
the preferred phthalate for medical devices because of its
properties which include maintaining flexibility at low
temperatures combined with a resistance to high temperature
sterilisation.
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Is it true that patients are being put at risk as a result of
exposure to DEHP from PVC medical devices?
No. There is no evidence to suggest that patients are at being
put at risk. To the contrary, PVC medical products have been used
for more than 50 years in healthcare establishments around the
world and there is not one known case of a patient having suffered
as a result. There are millions of healthy people today who have
benefited from having been treated with life-saving PVC medical
products.
One of the world’s leading manufacturers of medical
devices, Baxter, says that it believes that have been between five
and seven billion patient days of acute exposure and between one
and two billion patient days of chronic exposure to
DEHP-plasticised medical products.
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So, are they safe to use?
Used properly and in the way that they are, we believe –
as do the medical authorities – that they are safe to use. In
fact, in Europe, PVC containers for blood, blood components and for
aqueous solutions for intravenous infusion are the only type listed
for use in the European Pharmacopoeia. Other materials can only be
used subject to approval in each case by the national authority
responsible for licensing them.
Medical devices in Europe are strictly regulated by the
EU’s Medical Device Directive (93/42/EEC). In the USA they
are similarly regulated by the Federal Drug Administration,
FDA.
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But is it true that phthalates migrate from these products and
are being absorbed by patients?
Like many components of both man-made and natural products,
phthalate plasticisers may be absorbed in small quantities by the
fluids they come into contact with. This is a known occurrence and
therefore the safety of such products is regularly reviewed and
stringently monitored by both industry and regulatory
authorities.
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How are patients being exposed and by how much?
The potential exposure route to a plasticiser occurs when a
patient receives fluids intravenously. How much plasticiser is
released depends on the fluid properties, storage time, temperature
and the type of plasticiser used. However, the amount that might
migrate is very small and phthalates are quickly metabolised and
eliminated from the human body.
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What about the risk to dialysis patients or those in critical
care units who receive prolonged treatment using PVC products?
There is no evidence to suggest that they are at risk. Even the
amounts that such patients would be subjected to are too low to
cause concern. An independent review[1] that examined the health
risk to humans of exposure to DEHP, particularly via medical
devices, concluded that an increased cancer risk due to DEHP is
unlikely even among maximally exposed haemedialysis patients.
The European Union’s Scientific Committee on Medicinal
Products and Medical Devices has also published an Opinion on the
use of di(2-ethylhexyl) phthalate (DEHP) in medical devices saying
that it can make no recommendations to limit its use, even for the
most highly exposed patients.
Although the scientific committee report proposes that
additional research is conducted to monitor the situation, it says
"there are no reports concerning any adverse effects in humans
following exposure to DEHP-PVC, even in neonates or other groups of
relatively high exposure."
The Scientific Committee's Opinion, adopted at their meeting on
September 26, 2002, had been produced at the request of the
European Commission's enterprise directorate, following concerns
expressed by patient care groups.
"DEHP plasticised PVC has been used for several decades in
medical devices. The functional characteristics and processibility
of the material makes it very suitable for the construction of a
wide variety of these devices, some of which are crucial to the
delivery of care to critically or chronically ill patients", says
the report. "The contribution of DEHPPVC to the delivery of health
care should be taken into account in the consideration of the
potential risks of adverse effects of DEHP in these patients."
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It is being said that there is a cancer risk from DEHP. Is this
true?
Claims by environmental and healthcare groups that medical
patients may be exposed to a cancer risk as a result of being
treated using medical products containing the plasticiser are
unfounded. The World Health Organisation and the European
Commission have both conducted extensive reviews of DEHP but
neither has classified the phthalate as a human carcinogen. Health
Canada classifies it as ‘unlikely to be carcinogenic to
humans’.
In the United States, DEHP is listed as a probable human
carcinogen by the Environmental Protection Agency (EPA) but this is
based on rodent studies and there is disagreement even within the
EPA as to whether the classification is correct.
In rodent studies, during which DEHP was administered at very
high doses, there has been evidence of liver cancer. However, the
significant species differences that exist between the ways in
which a human liver and a rodent liver respond to DEHP means that
carcinogenicity in humans from DEHP exposure is extremely
unlikely.
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Is it true that DEHP causes human reproductive problems?
No. There is no evidence that phthalates cause human
reproductive problems. It is true that some phthalates, at high
dose levels, have been shown to cause reproductive effects in rats
and mice. However, the relevance of these findings to humans is
limited due to the dose level being far in excess of human exposure
and the fact that primates appear to be resistant to the
reproductive effects seen in rodents.
A number of studies in monkeys, especially a recent one carried
out in Japan, have shown that at extremely high dose levels
(500,000 times higher than expected human exposure) DEHP has no
effect on testes and ovaries.
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But isn’t DEHP labelled as harmful to reproduction?
Yes it is but this is based on hazard and not on risk. DEHP was
classified as a category 2 reproductive toxicant because adverse
effects have been seen when very large quantities are fed to
rodents. However, these effects have only been seen in ridents fed
with very large quantities of DEHP over a period of time. Such
doses are very significantly higher than would be generally
experienced by humans.
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Why are some phthalates, including DEHP, classified as
endocrine disrupters?
There is no evidence that any Phthalate plasticisers are human
endocrine disrupters.
Some phthalates cause reproductive effects at high doses in rats
and mice by a process which apparently involves the endocrine
system. However, these effects have only been seen at levels of
exposure many times higher than those experienced by humans.
Studies on non-human primates do not show adverse effects after
high phthalate exposure.
The Japanese authorities have recently confirmed that phthalates
should not be included among substances considered human endocrine
disrupters.
Within the past few years all the major phthalates have been
comprehensively risk assessed by EU Member State experts who have
conclusively agreed that they do not pose a risk to the general
human population. Some of these assessments are now published by
the European Chemicals Bureau and can also be accessed on this web
site
For more information on endocrine disruption please refer
to the Cefic Endocrine Information pages; the Cefic Long Range Research Initiative; and the
EU endocrine disrupters website
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The industry has claimed that the use of DEHP in blood bags
actually helps prolong the life of blood. Is this true?
Yes it the small amounts of plasticiser that migrates from a
blood bag does help preserve blood. This is another benefit of
using plasticised PVC. The amounts are so small that they do not
pose a health risk.
- Huber, W W, Grasi-Kraupp, B and Schulte-Hermann, R (1996)
Hepatocarcinogenic potential of di(2-ethylhexyl)phthalate in
rodents and its implications on human risk. Critical Reviews in
Toxicology, 26 (4), 365-481.
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