Questions and Answers

1.    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.

2.    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).

3.    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.

4.    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 40 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.

5.    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.

6.    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.

7.    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.

8.    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.

9.    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.

10.  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.

11.  But isn’t DEHP labelled as harmful to reproduction?

In line with EU classification and labelling legislation, DEHP is classified as a reproductive toxicant because reproductive effects have been seen in rodents when exposed to very high amounts of the substance. The classification therefore advises industrial users who handle DEHP as a raw material to avoid excessive exposure. In its everyday use as a constituent of PVC medical devices the levels do not pose a threat to human health or the environment.

12.  Why are some phthalates, including DEHP, classified as 
       endocrine disrupters?

We do not believe they are endocrine disrupters based on the wealth of scientific research that is available. They appear on some lists of ‘possible endocrine disrupters’ due to isolated studies which showed a possible link to estrogenic activity. However, these studies have now been superseded by more recent research and it has been proven not to be the case. As reported in the February 20 1999 issue of the Endocrine/Estrogen Newsletter, the US Food and Drug Administration (FDA) has conducted both in vitro and in vivo tests on DEHP and other phthalates and found them not to be oestrogenic.

13.  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.

14.  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.  

⁽¹⁾ 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.