Friday, September 10, 2010

Anti-malaria drug resistance worries stakeholders

…experts discourage ‘across the shelf’ drug purchases

Malaria prevention is one issue that has spurred researchers across the globe to effectively combat the parasite Plasmodium species, which is transmitted via infected mosquito bites. However, despite the use of prophylactic drugs like Fansidar, Quinine, Chloroquine, etc. in areas where mosquitoes are common, little has been achieved, even as issues of partial immunity development in individuals infected with the parasite have arisen.
Interestingly, research by the World Health Organisation (WHO) suggests that the best available treatment is a combination of drugs known as artemisinin-based combination therapies (ACT). Nonetheless, the discovery of low quality supplies of the drugs in some countries has given real cause for concern, besides dampening Nigerians confidence since evidence shows malaria is unrelenting in the level of devastation it causes.
Figures from National Malaria Control Programme (NMCP) show that 50 percent of the population will have at least one attack in a year, with malaria currently accounting for about 130 million clinically diagnosed cases and about 60 percent of all clinic attendance and 30 percent hospital admissions.
Furthermore, some Nigerians have complained of the inability of drugs regimens, including some Artemisinin based Combination Therapies (ACTs), to cure their malaria, prompting concerns from the Federal Ministry of Health.
Only recently, a survey of anti-malaria drugs in three African countries found that the drugs were of poor quality. The joint US and World Health Organisation (WHO) study discovered that up to 40 percent of artemisinin-based drugs in Senegal, Madagascar, and Uganda, failed quality tests. Also, researchers found out that between 26 and 44 percent of the malaria pills tested was of low quality, as some of the the drugs had included impurities or pills not containing enough active ingredients.
Although an inquest to authenticate these claims has been commissioned in Nigeria, medical experts opine that several things could account for the poor quality of the drugs.
Shilaj Chakravorty, consultant pathologist, BT health and Diagnostic centre, Lagos State University Teaching Hospital, (LASUTH), Ikeja, noted that what can cause treatment failure of malaria include incorrect drug dosage, poor drug quality, non-compliance of drug regimen and consumption of substandard anti-malaria drugs, as insufficient active ingredients could hinder the effectiveness of the ACT drug, to mention a few.”
According to him, the aforementioned cause of treatment failure contributes to drug resistance, as it exposes the malaria parasite to sub-optimal drug levels. “Across-the-shelf purchase of anti-malaria drugs and advertisement of various types of anti-malaria drugs in the media, have led people to indulge in self-medication without undergoing medical tests to ascertain whether malaria really is the cause of fever. As a result, inappropriate medication leads to development of resistant strains of the malaria parasite. One should also be aware that cross-resistance is common, which means a parasite developing resistance to one drug will show resistance to any other drug within that drug family. However, as all fever is not malaria, diagnosis for malaria must be done and treated within 24 hours of the onset of symptoms in line with WHO stipulation,” he said.
To Wellington Oyibo, consultant medical parasitologist, college of medicine, University of Lagos, Idi-araba, Lagos, tolerance to ACT, which was reported in Thailand and Cambodia late 2008, showed that when ACT was administered, early stages of the parasite in blood was not cleared but tolerated.
Oyibo disclosed that though the older stages of the malaria parasite were cleared at the tolerance stage, it took a longer time for both parasites and clinical symptoms to be cleared, which became an early warning sign of the onset of resistance.
“There was full resistance reported in 2009 in the Thailand/Cambodia boarder, i.e. ACT resistance. However, in Nigeria, there has been no scientific evidence of resistance ACT resistance though some individual observations have been shared among health workers,” said the parasitologist.
Recently, The Federal Ministry of Health (FMOH) carried out a Drug therapeutic efficacy testing (DTET) in seven centres to ascertain assertions of ACT resistance. The last testing was done in 2003 to ascertain chloroquine resistance. However, globally, a WMNET network is trying to track the ACT resistance gene, as is the case with prophylactic drugs like chloroquine and Fansidar.
It is noteworthy to state that due to poverty, Nigerians still purchase drugs across the counter –like Chloroquine and Fansidar which are already known to be resistant to the malaria parasite. Global Fund through the FMOH is making ACT drugs free in some private and government health institutions and at a subsidised price in private institutions. In this manner, Nigerians would be able to access drugs easily without much difficulty.
For Oyibo, “The government should scale up the supply of ACT drugs by global fund to ensure that Nigerians have access to it. With access to ACTs, the continued use of chloroquine and Fansidar should be stopped forthwith so as to reduce the continued spread of malaria parasite resistance genes in the population. However, for clinical managers, good diagnosis and data management must be in place to manage issues relating to malaria prevention. Caregivers and Nigerians should desist from using Chloroquine and Fansidar for the treatment of malaria ….”
The reason is simple: if ACT fails in the treatment of malaria, where are Nigerians going to take succour from? That is why all hands should be on deck. The well considered policy on malaria diagnosis and treatment which requires the confirmation of malaria through rapid diagnosis or microscopy is expected to curtail the overuse of anti-malaria drugs and thus reduce drug pressure.

..By Alexander Chiejina

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