The in vitro effect of the following antimicrobial agents on Toxoplasma gondii tachyzoites were studied: artemisinin ether (arteether), cycloguanil hydrochloride (cycloguanil), mefloquine, primaquine phosphate, and quinine sulfate, as well as the calcium channel blocker verapamil and the calmodulin inhibitor trifluoperazine hydrochloride. Arteether at > or = 0.5 micrograms/ml and cycloguanil at > or = 1.0 micrograms/ml inhibited T. gondii in vitro. Cycloguanil (2.5 micrograms/ml) combined with a noninhibitory concentration of sulfadiazine (25 micrograms/ml) inhibited T.
An assay was developed measuring the disruption of rosettes between Plasmodium falciparuminfected (trophozoites) and uninfected erythrocytes by the antimalarial drugs quinine, artemisinin mefloquine, primaquine, pyrimethamine, chloroquine and proguanil. At 4 hr incubation rosettes were disrupted by all the drugs in a dose dependent manner. Artemisinin and quinine were the most effective anti-malarials at disrupting rosettes at their therapeutic concentrations with South African RSA 14, 15, 17 and The Gambian FCR-3 P. falciparum strains.
The American Journal of Tropical Medicine and Hygiene
The in vitro activities of doxycycline, chloroquine, quinine, amodiaquine, artemether, pyrimethamine, and cycloguanil were evaluated against Plasmodium falciparum isolates from Senegal (Dielmo and Ndiop), using an isotopic, micro, drug susceptibility test. The 71-50% inhibitory concentration (IC50) values for doxycycline ranged from 0.7 to 108.0 microM and the geometric mean IC50 for the 71 isolates was 11.3 microM (95% confidence interval = 9.5-13.4 microM).
The synergistic antifolate combination of chlorproguanil with dapsone (CPG-DDS; LAPDAP) is being developed by a public-private partnership as a low-cost treatment for uncomplicated falciparum malaria. LAPDAP is rapidly eliminated from the body, giving it low selection pressure for drug resistance. Clinical cases with sulphadoxine-pyrimethamine (SP)-resistant infections acquired in Africa have been predicted to be responsive to LAPDAP, and clinical evidence is available to support this.
Clinical Infectious Diseases: An Official Publication of the Infectious Diseases Society of America
In an open-label trial carried out on the northwest border of Thailand, 1596 patients with uncomplicated multidrug-resistant falciparum malaria were randomly assigned to receive atovaquone-proguanil, atovaquone-proguanil-artesunate, or artesunate-mefloquine and were followed up for 42 days. All 3 regimens were highly effective and well tolerated. Fever duration and parasite clearance times were significantly shorter among patients who received artesunate (P<.001).
A modified fixed-ratio isobologram method for studying the in vitro interactions between antiplasmodial drugs is described. This method was used to examine the interactions between atovaquone, proguanil, and dihydroartemisinin. The interaction between atovaquone and proguanil was synergistic against atovaquone-sensitive strains K1 and T996; however, there was a loss of synergy against atovaquone-resistant strain NGATV01 isolated after Malarone (the combination of atovaquone and proguanil) treatment failure.
BACKGROUND: There is no safe, practical, and effective treatment for pregnant women infected with multidrug-resistant Plasmodium falciparum. METHODS: We recruited pregnant Karen women in the second or third trimesters of pregnancy who had uncomplicated falciparum malaria for a randomized, open-label trial with a restricted sequential trial design of 7 days of supervised quinine (SQ7) versus 3 days of artesunate-atovaquone-proguanil (AAP). RESULTS: Eight-one pregnant women entered the study between December 2001 and July 2003; 42 were treated with SQ7 and 39 were treated with AAP.
The American Journal of Tropical Medicine and Hygiene
Combinations are set to become the mainstay in treatment and prophylaxis of malaria due to Plasmodium falciparum. Various antimalarials have been implicated in cardiotoxicity via prolongation of the QTc interval. Atovaquone-proguanil is an effective and increasingly popular antimalarial choice when used alone or with artesunate in areas of drug resistance. We report the results of an investigation carried out on the Thai-Burmese border in 42 patients randomized to receive either atovaquone-proguanil or atovaquone-proguanil-artesunate for three days.
The burgeoning problem of malaria in the developing world and the relentless march of drug resistance demand that we continue to seek new chemotherapeutic strategies. Given the enormous expense of developing and marketing new chemical entities, we often rely on an increased understanding of the pharmacology of older drugs and judicious use of drug combinations. Development is being driven primarily by public-private partnerships from academic investigations.
BACKGROUND: Malaria infection during pregnancy is a major public health problem. Due to increasing resistance to Chloroquine and Sulphadoxine/Pyrimethamine, the Ugandan national policy on malaria treatment was changed in 2005 to Artemisinin-based combination therapy (ACT) as the first-line treatment for uncomplicated malaria. The policy recommends assessment of safety and efficacy of alternative drugs for treatment of uncomplicated malaria.