Science - June 5, 2014

‘Plant-based Viagra’ sometimes contains… Viagra

Text:
Rob Ramaker

Plant-based supplements can be contaminated with drugs without any mention of them on the packaging. Consumers seeking to boost their libidos, for example, could experience problematic side-effects.

Foto credit: Vinod Velayudhan

Noortje Reeuwijk demonstrates this in the thesis she defended on 23 May. For her research she analysed 71tablets, capsules and potions which claim to boost the sex drive. Approximately one in three turned out to contain active ingredients from drugs. The test was not intended to be a representative sample, however. Reeuwijk’s client, the Netherlands Food and Consumer Product Safety Authority, actively sought out the most suspect products.

In the course of her analyses, Reeuwijk found significant concentrations of the anti-impotence drug Viagra, among other substances. A contaminated supplement them can cause the same side-effects as the official drug. People with low blood pressure, for example, are advised against taking Viagra.

It is a funny business if apparent by-products of drug development turn up in plant-based supplements
Ivonne Rietjens

But the biggest concern for Ivonne Rietjens, professor of Toxicology and Reeuwijk’s supervisor, is the ‘sister substances’ of drugs such as Viagra. These substances differ slightly from the original, possibly thanks to manufacturing errors or a deliberately different production process. Little is known about the strength or safety of these substances. ‘What is more,’ says Rietjens, ‘it is a funny business if apparent by-products of drug development turn up in plant-based supplements.’

Contaminated production lines

The big question is, of course, how these drugs end up in supplements. An obvious assumption would be that producers deliberately add the substances. But, the researchers cautiously suggest: using contaminated production lines could explain these results as well. The NVWA has now acted against the sellers of the contaminated supplements, says Reeuwijk. But she indicates that it is difficult to control the business. ‘Suppliers come up fast through the internet, and then disappear fast as well.’ The market for plant-based supplements in Europe is hardly regulated at all. They are not covered by the regulations for medicinal plants, foods and medicines.


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