Adulterated impotence drugs spark call for stricter regulations
A 28-year-old man fell ill after taking a health product for male erectile dysfunction, which was found to contain a compound similar to sildenafil, which is sold commercially as Viagra.
The case was reported by the Hospital Authority Toxicology Reference Laboratory, which found more than half of 26 similar over-the-counter health products were adulterated with drug analogues - structurally similar but chemically modified versions of existing drugs.
'Such analogues are difficult to detect by ordinary laboratory methods and might be used in an attempt to evade regulatory inspection,' Tony Mak Wing-lai, a consulting chemical pathologist at the laboratory, said in a research paper to be published in the Hong Kong Medical Journal in October. 'Without going through the stringent drug-testing process, the adverse effects of these chemicals remain largely unknown and unpredictable.'
The man also developed an unsteady gait and frequent falls - symptoms of ataxia, a loss of muscle co-ordination - for one week last summer.
A review of his medication revealed he had taken a health product for eight days before the symptoms appeared. The product was available at a convenience store, with a claim it contained natural herbal substances for improving sexual function.
Drug-related ataxia was suspected and a chemical analysis found the product had been adulterated with an analogue of sildenafil.
To further investigate the extent of drug analogue adulteration in male erectile dysfunction health products, the laboratory bought 25 such products, which all claimed to contain herbal ingredients only.
Chemical analysis showed that one contained sildenafil, while 14 contained different kinds of drug analogues.
'The rate of concealed drug analogues in male erectile dysfunction health products is alarmingly high,' said Dr Mak, who called for urgent controls.
All western medicines in Hong Kong are required to be registered with the Department of Health. But under the current law, drug analogues are not recognised as medicines.
The lawmaker representing the medical sector, Kwok Ka-ki, called on the government to plug the loophole and increase the regulation of all health foods.