Artemisinin combination therapy

Artemisinin Combination Therapy

Artemisinin Combination Therapy (ACT) is a treatment regimen used to combat malaria, particularly the strains caused by the Plasmodium falciparum parasite. This therapy combines an artemisinin derivative with another antimalarial drug to enhance efficacy and reduce the risk of resistance.

Background

Artemisinin, derived from the sweet wormwood plant (Artemisia annua), was discovered by Chinese scientist Tu Youyou in the 1970s. It is known for its rapid action against the malaria parasite. However, when used alone, artemisinin can lead to the development of resistance. To counter this, it is combined with other antimalarial drugs, forming what is known as Artemisinin Combination Therapy.

Mechanism of Action

Artemisinin and its derivatives, such as artesunate and artemether, work by producing free radicals that damage the proteins and membranes of the malaria parasite. The partner drug in ACTs, such as lumefantrine or amodiaquine, has a longer half-life and helps to clear any remaining parasites, preventing recrudescence.

Common Combinations

Several ACTs are recommended by the World Health Organization (WHO) for the treatment of uncomplicated malaria:

• Artemether-lumefantrine (AL): This is one of the most widely used ACTs and is known for its effectiveness and safety profile.
• Artesunate-amodiaquine (AS-AQ): Commonly used in Africa, this combination is effective against chloroquine-resistant strains.
• Artesunate-mefloquine (AS-MQ): Used in Southeast Asia, particularly in areas with multidrug-resistant malaria.
• Dihydroartemisinin-piperaquine (DHA-PPQ): Known for its long half-life, making it effective in preventing reinfection.

Resistance

Resistance to artemisinin has been reported in the Greater Mekong Subregion. This resistance is characterized by a slower clearance of parasites from the bloodstream. To combat this, the WHO recommends the use of ACTs with effective partner drugs and continuous monitoring of drug efficacy.

Global Impact

ACTs have significantly reduced malaria morbidity and mortality worldwide. They are a cornerstone of malaria control programs and have been instrumental in the progress towards malaria elimination in several regions.

Challenges

Despite their success, ACTs face challenges such as drug resistance, counterfeit medications, and accessibility in remote areas. Efforts are ongoing to develop new antimalarial drugs and improve the delivery of existing treatments.

Also see

• Malaria
• Plasmodium falciparum
• Antimalarial drugs
• Drug resistance
• World Health Organization