Researchers have linked a large number of malaria medicines to mental and nerve problems in patients.
An extensive study by the Kenya Medical Research Institute, Thika Level 5 Hospital, Kenyatta University, University of Oxford (UK), has revealed that most current malaria drugs are too toxic to users.
They are now recommending the development of safer medicines for the treatment of malaria.
“Efforts to develop new effective and safer antimalarial drugs should be accelerated,” recommends the study published in the journal Wellcome Open Research.
Wellcome Open Research is a relatively new journal linked to Welcome Trust of the UK, which funded this study led by Mary A Bitta of KEMRI-Wellcome Trust Research Programme in Kilifi.
The most dangerous medicines contain the compounds amodiaquine and sulfadoxine.
“Of individual antimalarial drugs still on the market, mental and neurological problems were most common with the use of sulfadoxine for prevention and amodiaquine for acute malaria treatment,” it said.
Even the most used antimalarial in Kenya today, which contains the compound lumefantrine, has been found to cause mental and nerve problems. The problems, the study says, range from headaches, dizziness, seizures, convulsions, loss of vision, loss of hearing, sleep disturbances to personality changes.
The team now wants more studies to determine the long term effects of these drugs on users. “Survivors of severe malaria develop a wide range of neural problems including epilepsy, language deficits, motor and sensory deficits.”
Bitta and her team had trolled 2,349 malaria treatment studies from all over the world covering up to last July and finally settled on 51.
The researchers put into consideration that malaria medicines and the disease may have similar effects on the patients such as mental disturbances. But the same mental disturbances were reported in individuals who had taken the medicines for prevention.
One of the most controversial malaria drug is mefloquine. In this particular study, mefloquine was associated with mental and neurological manifestations in eight out of 10 cases investigated.
But despite a global outcry over the serious side effects associated to mefloquine, a drug containing this compound was recently registered in Kenya. Mefloquine used for malaria prevention and going by the brand name Lariam is banned by the US, Australian and the French militaries for its link to serious mental problems
On Tuesday, the Veterans Affairs Committee of Canada released a report on the effects of mefloquine on its soldiers who had been deployed to East Africa in the 1990s. The solders, through their doctors, claimed to have suffered serious side effects, including hallucinations, severe depression, sleep deprivation and anxiety after using mefloquine.
Mefloquine, however, continues to be sold over the counter in local pharmacies, with a newer combination of mefloquine and artesunate registered in the country recently.
In recent years, the World Health Organisation (WHO) has recommended the use of combined compounds in malaria medicines to delay the development of drug resistance. However, the new study says this could be increasing their toxicity to patients.
“Such combinations may increase levels of mental and neurological manifestations, probably from cumulative toxicity of individual drugs,” says the study.
The researchers specifically want individuals on the combined treatment of pyrimethamine and sulphadoxine closely monitored because they face possible serious side effects from the medications.
It is time, Bitta says, for health authorities to set up strong drug market surveillance systems for malaria medicine to capture those which could be detrimental to public health. This could be a tall order, considering the high number of malaria medicines in the local market. A 2013 Ministry of Health and donor monitoring report of antimalarial say 42 per cent of malaria drugs in the local market may not be registered.
A 2005 report by the Kenya Medical Research Institute showed there were 218 antimalarial drugs circulating in the Kenyan market.
Almost half of malaria drugs in the local market are of unknown quality, according to the ACTwatch, a global medical products watchdog.
WHO has set global standards for the manufacture of malaria medicines which are used as the acceptable benchmark in the market.
But a study published by the ACTwatch in May shows widespread availability of malaria drugs without the global quality approval. The study covered eight African countries — Kenya, Benin, DRC, Madagascar, Nigeria, Tanzania, Uganda and Zambia — between 2009 and 2015.