Substandard Medicines

"A high percentage of medicines circulating on national markets", in ten Sub-Saharan African countries, "are of substandard quality and thus may contribute to the growth of drug-resistant strains of Plasmodium falciparum, the most virulent form of malaria." First results of the "large-scale study of key antimalarial medicines" were released for Madagascar, Senegal, and Uganda by the Promoting the Quality of Medicines (PQM) Program, a USAID-funded program.

"Within Madagascar, Senegal and Uganda, the study" focused "on artemisinin-based combination therapy (ACT) products, currently the WHO's recommended form of first-line treatment for uncomplicated malaria, and sulfadoxine-pyrimethamine (SP) products, often used for preventative treatment of malaria during pregnancy." Researchers collected samples from "public and regulated private sectors" and from "informal markets, as many patients obtain their medicines from these sources."

"Substandard and counterfeit versions of antimalarial medicines are highly problematic throughout Africa, Asia and Latin America because of the direct threat they pose to the lives of individual patients as well as their contribution to the development of drug-resistant strains of these diseases." The "study found that approximately 44 percent of sampled medicines from Senegal, 30 percent of samples from Madagascar, and 26 percent of samples from Uganda that underwent full quality control laboratory testing failed such testing and were thus substandard."

"Substandard" medicines are classified as "those that do not meet the quality specifications set for them, primarily because they do not contain the correct amount of the active ingredient(s), do not dissolve properly in the body or include unacceptable levels of potentially harmful impurities." According to the released results, "[n]o samples in the full study completely lacked the active ingredient(s). The results also showed that, as a general rule, when a brand passed or failed in one country, it would also pass or fail in other countries. This indicates that the problem of quality is created at the source, rather than during passage through the distribution chain."

Substandard medicines were not limited to informal markets, and their point of sale varied by country. "In Madagascar, for instance, poor quality medicines appear to be widespread across regions and not limited to any particular type of distributor [public, private, or informal]. In Uganda, samples fared much better in the public sector than in the country's private sector. Despite overall failure rates, this was one of the bright spots the study revealed; in Uganda's public sector, all ACT and SP samples passed quality tests."

The purpose of this study was reveal "the prevalence of substandard antimalarials in Sub-Saharan Africa, which are believed to contribute to antimicrobial resistance of Plasmodium falciparum. Already, Plasmodium falciparum has become resistant to traditional" treatments "such as chloroquine, and more recently to SP products. The sustainability of treatment success depends to a large extent on preventing Plasmodium falciparum's exposure to incomplete doses of these medicines to minimize the possibility of the emergence of drug resistance."

Source:
US Pharmacopeia (2010, February 10). One-third of antimalarial medicines sampled in three African nations found to be substandard. http://vocuspr.vocus.com/vocuspr30/Newsroom/ViewAttachment.aspx?SiteName=USPharm&Entity=PRAsset&AttachmentType=F&EntityID=108111&AttachmentID=f2e22216-44a5-41a2-a9bc-464b7a98e3bf

The Threat of Drug Resistant Malaria

Recent tests indicate that the most common malaria strains are becoming resistant to combination treatments in vulnerable areas. "Selected trials" showed "high failure rates for some combinations" of medicines. Anti-malarial treatments must be questioned, particularly in susceptible regions (Wiley).

The most common type of malaria parasite causes uncomplicated malaria, which is a mild form of the disease. However, if this strain remains untreated, it can develop into a life-threatening condition. "Resistance" of this strain "to the older antimalarials has led the WHO to recommend treatments combining" a fast-acting drug with a "longer-lasting drug to combat resistance."

Malaria can be a difficult disease to cure and is most often treated with a combination of medicines. During the recent tests, "there were examples of treatment failure rates above 10% for all evaluated combinations." According to the WHO, this exceeds the "maximum allowable failure rate for a first line antimalarial" treatment.

A recently introduced drug, dihydroartemisinin-piperaquine, performed well when compared to the standard treatment of artemisinin-based combination therapies (ACTs). This new treatment "offers another potential first-line therapy for the disease".

"Patterns of resistance change from place to place and over time," so continued testing of infected individuals and monitoring of progress is necessary to ensure successful treatment. These research and medical programs are costly, and severely underfunded. If you would like to contribute money to malaria research, please visit the following sites.

Anti-malaria agencies:

• Roll Back Malaria Partnership: Index of non-profit organizations that fight malaria (and need donations)
• United Nations Foundation: With your donation you are helping us expand the worldwide fight against disease, poverty, climate change, and conflict

(Infectious bite is not currently accepting donations. Please see the appropriate agencies for information on donations)

Source:
Wiley-Blackwell. "Continued Vigilance Against Drug-resistance Malaria Is Needed." ScienceDaily 7 July 2009. 9 July 2009 < http://www.sciencedaily.com­ /releases/2009/07/090707201209.htm >.

Advances Against Malaria | Combination Treatment

New studies conducted with children in Burkino Faso have shown that "in combination with newer malaria drugs, methylene blue prevents the malaria pathogen in infected persons from being re-ingested by mosquitoes and then transmitted to others and is thus twice as effective as the standard therapy" (University).

Methylene blue is one of the oldest synthetic treatments of malaria. In 1891, Paul Ehrlich identified its success at treating the disease (Schirmer). The chemical fell out of favor because of its cosmetic side-effects: whites of the eyes acquire a blue tint (image) and urine turns green.

Methylene blue is relatively cheap to produce and may see a resurgence in use since "combination therapies are twice as effective against gametocytes as the standard therapy" (University).

Sources:
Schirmer H, Coulibaly B, Stich A, et al. (2003). "Methylene blue as an antimalarial agent--past and future". Redox Rep 8: 272–276. doi:10.1179/135100003225002899

University Hospital Heidelberg. "Spread Of Malaria Parasites Curbed With Combination Of Methylene Blue And New Malaria Drugs." ScienceDaily 26 May 2009. 24 June 2009