Researchers from the Wellcome Trust-Mahosot Hospital-Oxford University Tropical Medicine Research Collaboration warned that drugs with incorrect doses, or with erroneous active ingredients, could increase drug resistance in malaria patients.
The report, which called for urgent action to save millions of lives worldwide, identified two problems: fake drugs being sold fraudulently, and substandard drugs arising from poor manufacturing.
The recommended antimalarial drugs are artemisinin derivatives, used as monotherapy or in combination with other drugs.
The researchers gathered medication data from 11 nations in Africa between 2002 and 2010.
They identified many drugs used to treat malaria that contained erroneous active ingredients, treating the symptoms but not the disease itself.
In addition, they identified drugs with small quantities of the correct active ingredient – sufficient to pass chemical tests, but more likely to cause resistance to artemisinin without benefiting the patient.
Some of the fake antimalarials were traced to China.
Study leader Dr Paul Newton said: “Malaria can be readily treated with the right drugs of good quality, but poor-quality medicines – as well as increasing mortality and morbidity – risk exacerbating the economic and social impact of malaria. Worse still, they encourage drug resistance, potentially resulting in the failure of artemisinin treatments. Failure to take action will put at risk the lives of millions of people, particularly children and pregnant women.”
He also recommended that clinicians fighting malaria rely exclusively on combination therapies, which are harder to counterfeit.
“This research is very worrying and should act as an early warning,” said Dr Jimmy Whitworth, Head of International Activities at the Wellcome Trust. “We have already begun to see the emergence of drug-resistant malaria parasites in South-East Asia; substandard and counterfeit antimalarials and the availability of artemisinin monotherapies threaten to lead to the spread of drug resistance in Africa. If this happens, the effect could be devastating on efforts to control malaria in Africa.”
Malaria caused approximately 781,000 deaths worldwide in 2009, according to the World Malaria Report 2010.