Academics said some of the pCMs they tested — which are widely believed by consumers to be 'natural' and safe — can pose sever dangers to health.
The new analysis, published in the British Journal of Clinical Pharmacology, documents 404 cases involving the use of 487 adulterated pCMs or health products, containing a total of 1,234 adulterants.
The researchers said various reports have documented the adulteration of pCMs and health products with undeclared agents, including prescription drugs, drug analogues, and banned drugs. Such adulteration can have serious and even fatal consequences.
To examine the problem, Tony Wing Lai Mak, Chor Kwan Ching, and their colleagues at Hong Kong's only tertiary referral clinical toxicology laboratory retrospectively reviewed cases involving the use of adulteratedc pCMs or health products referred to the centre from 2005 to 2015.
The adulterants consisted of approved drugs, banned drugs, drug analogues, and animal thyroid tissue.
The paper stated: "The six most common categories of adulterants detected were NSAIDs (17.7%), anorectics (15.3%), corticosteroids (13.8%), diuretics and laxatives (11.4%), oral anti-diabetic agents (10.0%) and erectile dysfunction drugs (6.0%). Sibutramine was the most common adulterant (n = 155)."
Sibutramine, an anorectic that has been withdrawn from the market due to its association with increased cardiovascular events and strokes, was the single most common adulterant identified.
The sources of illicit products included over-the-counter drug stores, the Internet, and Chinese medicine practitioners. Significantly, 65% of patients experienced adverse effects attributable to these illicit products, including 14 severe and two fatal cases.
Psychosis, iatrogenic cushing syndrome, and hypoglycaemia were the three most frequently encountered adverse effects.
"These illicit pCMs and health products pose severe health hazards to the public,” said Dr Mak.
"Previous reports of pCM and health product adulteration were mainly routine surveillance data or case reports / series with a small number of affected patients. The present study, to our knowledge, is the largest case series that reports an overview of the use of various adulterated pCMs and health products and the resulting adverse effects."
They added that the findings should serve as a serious warning to consumers and health professionals.
"The public should be educated not to consume pCMs and health products from dubious sources, and frontline clinicians should have a high index of suspicion," said Dr Ching.
We recently reported how researchers in China were calling for quality markers to affirm the safety and efficacy of TCM products.
"Q-marker-based quality standards will be regarded as a more scientific quality-control approach for TCM. It is also a general conception that Q-marker-based quality control for Chinese medicine production…would be more beneficial for transitivity and traceability in the TCM production process,” they wrote in the journal Acta Pharmaceutica Sinica B.
Source: British Journal of Clinical Pharmacology
“Adulteration of Proprietary Chinese Medicines and Health Products with Undeclared Drugs: Experience of a Tertiary Toxicology Laboratory in Hong Kong”
Authors: Chor Kwan Ching, et al.