Heart patients are at risk from a substandard anti-clotting drug, experts warned today.
German researchers testing batches of a clot-busting drug used by heart attack victims have found wide differences in the make-up of the ingredients and the product's purity.
Publishing the results of their tests in the European Heart Journal, heart specialists said worldwide action was needed to stop of substandard life-saving drugs putting patients' lives at risk.
Dr Peter Hermentin and his team in Marburg tested 21 samples of streptokinase, a clot-busting or fibrinolytic drug widely used in some non-EU European countries, Brazil, China and Pakistan.
They found that only three matched the minimum clot-busting requirements set out by the European Pharmacopaeia - the European authority on the quality and safety of medicines. They also discovered differences in the composition and purity of the samples.
Dr Hermentin said: "The dose of fibrinolytic agents such as streptokinase must be carefully controlled to maximise therapeutic activity while avoiding adverse effects. Too low a dose won't restore blood flow in the artery and too high a dose could cause a bleed in the brain.
"While we analysed only one sample from most of the batches ... and therefore can't generalise from our results, there are potentially serious clinical implications.
"The discrepancy between claimed and actual activity of many streptokinase preparations could cause life-threatening situations in severely ill patients."
In an editorial in the journal, Dr Felicita Andreotti and Dr Filippo Crea said raising awareness of the dangers of poor quality drugs may cause some patients excessive worry, but lack of vigilance could lead to distrust among consumers and professionals.
Dr Andreotti, from the Catholic University Medical School in Rome, said she found it "astonishing" that only three of the samples tested by the German team met the European safety requirements.
"How can consumers and health professionals be sure the drugs they use are safe and effective," she asked.
She said controlling the quality of the drug once it gets on the open market was difficult due to insufficient post-marketing control to curb the making and trading of substandard or counterfeit medicines.
"The World Health Organisation estimates that up to a tenth of the world's drug trade and a quarter in developing countries consists of fakes. Controlling this phenomenon clearly constitutes a global challenge," Dr Andreotti said.
She added that several steps were needed to improve surveillance of drugs, including using radio frequency or other unique traceable tags on products and tougher penalties for illegal manufacture. "Getting this right is a global responsibility," she said.
