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Query: UMLS:C0024530 (malaria)
 44,886 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

New quick-acting blood schizontocides are needed to contain the spread of multiple drug resistant strains of P. falciparum and for the treatment of the cerebral malaria cases. A multiple drug resistant strain of P. yoelii nigeriensis resistant to mefloquine (128 mg/kg x 6 days), quinine (300 mg/kg x 7 days) and chloroquine (64 mg/kg x 8 days) was found to be completely susceptible to arteether (a 30:70 mixture of alpha and beta enantiomers) and a dose of 5 mg/kg x 3 days by i.m. route was curative in Swiss mice. Artemisinin at 50 mg/kg x 7 days had only suppressive action against this strain.
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PMID:Antimalarial efficacy of arteether against multiple drug resistant strain of Plasmodium yoelii nigeriensis. 277 60

Artemisinin is a novel antimalarial drug isolated in China from the wormwood plant Artemisia annua L. Studies with rodent malaria were carried out to detect antagonism and synergism with a variety of antimalarial drugs. Isobolograms of drug interaction were plotted at the ED90 level. With a normally susceptible strain of Plasmodium berghei, marked potentiative synergism was found with mefloquine, tetracycline and spiramycin. There was some synergism also with primaquine. Combinations of artemisinin with dapsone, sulfadiazine, sulfadoxine, pyrimethamine, pyrimethamine/sulfadoxine and cycloguanil showed antagonism. A high degree of potentiation was shown between artemisinin and primaquine with a primaquine-resistant strain, whilst the combination with mefloquine showed enhanced potentiation with a mefloquine-resistant strain. Combinations of artemisinin with mefloquine, primaquine, tetracycline or clindamycin showed marked potentiation with an artemisinin-resistant strain. The mechanisms underlying the drug interactions observed are discussed.
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PMID:The effect of combinations of qinghaosu (artemisinin) with standard antimalarial drugs in the suppressive treatment of malaria in mice. 332 41

Since the sixties, the emergence of malarial parasites resistant to the most potent anti-malarials has posed a serious problem to the therapy of malaria. Qinghaosu, a new sesquiterpene isolated from a Chinese medicinal herb Qing-hao (Artemisia annua Linn) is being used for the treatment of malaria in China with good results even in cases resistant to common anti-malarial agents. In this paper, a sensitive method of high specificity using TLC for the determination of Qinghaosu in biological specimens and in the study of the metabolism of the drug in rats is described. Qinghaosu was shown to be completely and rapidly absorbed after oral administration. However, a very low plasma level was obtained even after a dose of 300 mg/kg. Liver was found to be the chief site of its inactivation. When Qinghaisu was given intramuscularly, significant and more persistent plasma levels were detected. Qinghaosu was shown to pass the blood-brain and blood-placenta barriers after i.v. injection. Very little unchanged Qinghaosu was found in the urine and feces in 48 hours regardless of administration route (i.v., i.m. or p.o.).
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PMID:Metabolic fate of Qinghaosu in rats; a new TLC densitometric method for its determination in biological material. 402 21

A prospective trial in 80 patients randomly allocated to four antimalarial treatment regimens--mefloquine plus pyrimethamine-sulfadoxine ('Fansidar'); mefloquine plus qinghaosu; mefloquine, fansidar, and qinghaosu; and qinghaosu alone--was carried out on Hainan Island, China, in patients with chloroquine-resistant falciparum malaria. A radical cure with slight side-effects was obtained with mefloquine plus fansidar; the addition of qinghaosu greatly increased the rate of parasite clearance with no additional side-effects. Qinghaosu alone had a rapid rate of parasite clearance, no side-effects, but a high recrudescence rate. These antimalarial drugs seem to act at different stages of the asexual parasite cycle and their most efficient use may depend on when in the course of the disease they are given. Because of the continuing appearance of drug-resistant strains of Plasmodium falciparum combination drug therapy is now indicated, but which drugs and how best they should be used remains to be decided.
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PMID:Randomised comparative study of mefloquine, qinghaosu, and pyrimethamine-sulfadoxine in patients with falciparum malaria. 615 Mar 65

Twenty-seven patients with gametocytes of Plasmodium falciparum (PF) were divided into groups A, B, and C. A daily dose of 1200 mg artemisinin was given for 5 days to group A, a state dose of 750 mg of mefloquine to group B and a single dose of 750 mg mefloquine combined with 45 mg primaquine to group C. After treatment, the gametocyte count was taken daily, and infectivity of the gametocytes to Anopheles dirus via membrane feeding was also studied. Results showed that in group A, the density of gametocyte and infectivity were significantly reduced on days 4, 7, 14 and 21 after treatment; In group B, the gametocytes were significantly reduced on days 7, 14 and 21 and infectivity was significantly cut down on days 14 and 21 after medication. In group C, gametocytes disappeared in 5 out of 9 patients with failure of infecting mosquitoes in all 9 patients on day 4 after treatment. These indicate that artemisinin can effectively influence the infectivity of gametocytes of PF. Artemisinin is much better in blocking the transmission of PF malaria than mefloquine.
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PMID:The infectivity of gametocytes of Plasmodium falciparum from patients treated with artemisinin. 780 66

For the treatment of patients with acute falciparum malaria, the combination of artemisinin as a single dose with a single dose of mefloquine was studied in 4 separate prospective trials, comprising 405 adults and 139 children with uncomplicated falciparum malaria in 2 in-patient and 2 rural out-patient studies in Viet Nam. Adults received oral artemisinin and children artemisinin suppositories. Randomized comparative treatment schedules were: artemisinin alone for 5 d, mefloquine-sulfadoxine-pyrimethamine (MSP), or quinine plus sulfadoxine-pyrimethamine (SP). Parasite clearance times (PCT) were rapid for artemisinin treated inpatients (90%: 14.8-20.4 h) but also for patients receiving MSP (PCT 90%: 18.0 h) and quinine (PCT 90%: 22.5 h). The recrudescence rate (RI) during a 28 d follow-up period among the patients given artemisinin plus mefloquine was 15% in the adult in-patients and zero in the adult and children out-patients. RI in the artemisinin 5 d treatment group was 33.3%; among those given artemisinin plus SP it was 47.3% in in-patients and in out-patients 46.1%. In the MSP treated out-patients RI was 1.5% in adults and zero in children. Artemisinin as a single dose (oral in adults and as a suppository in children) in combination with mefloquine was effective in rapidly lowering parasitaemia and in preventing recrudescence in hospital in-patients and in out-patients attending a rural health clinic. MSP alone as a single dose also rapidly reduced parasitaemia (but not as quickly as the artemisinin-mefloquine combination in out-patient children) and prevented recrudescence.
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PMID:Single dose artemisinin-mefloquine treatment for acute uncomplicated falciparum malaria. 788 73

27 patients with gametocytes of P. falciparum were divided into groups A, B and C. 1,200 mg of artemisinine was given as a daily dose for 5 days to group A, 750 mg of mefloquine plus 45 mg of primaquine as a single dose to group C. After medication, gametocyte count was observed daily in addition to the infectivity of gametocytes of P. falciparum to Anopheles dirus. In group A, the density of gametocytes and the infectivity were significantly reduced on days 4, 7, 14 and 21 during the study. In group B, the density of gametocytes was significantly reduced on days 7, 14 and 21 and the infectivity was obviously lowered on days 14 and 21 after medication. In group C, gametocytes disappeared in 5 out of 9 patients with the failure of infection to mosquitoes on day 4 after treatment. This indicates that artemisinine can effectively influence the infectivity of gametocytes of P. falciparum. Artemisinine is superior to mefloquine in blocking the transmission of P. falciparum malaria.
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PMID:[The infectivity of gametocytes of Plasmodium falciparum from patients treated with artemisinine]. 792 59

By means of 5 case reports the successful use of an new blood schizontocide against plasmodium falciparum infections is demonstrated. The local patients with severe malaria were treated in the German UN-hospital in Cambodia. Cerebral, pulmonary and haemolytic complications dominated. Intramuscularly artemether, a synthetic Qinghaosu-derivative, was combined with already used antimalarials. All patients survived, regained consciousness and were without fever after administering artemether within 48 to 72 hours. The complications were controlled by mandatory ventilation, blood transfusions, fluid balance and blood sugar monitoring. With artemether we will get a well tolerated and quickly effective schizontocide. In order to avoid recrudenscence and fast drug resistance it should be combined with a tetracycline and in consequence supplemented through a second schizontocide.
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PMID:[Complicated malaria tropica--therapy with artemether]. 802 24

The preparation of artemether from artemisinin is reviewed. Firstly, the extraction of artemisinin from Artemisia annua is described and an estimation of the yield per hectare based on literature data is given. Artemisinin is reduced with sodium borohydride to produce dihydroartemisinin as a mixture of epimers. The mixture is treated with methanol and an acid catalyst to provide artemether. Increasing demand for use of artemether places pressure on the supply of artemisinin, and an alternative means of preparing the drug from artemisinic acid, an abundant constituent of A. annua, which could triple current yields, is described. In anticipation of problems of drug resistance emerging with the continued use of artemether and artesunate to treat malaria, development of new derivatives of artemisinin which have enhanced stability is required. Examples of such derivatives which have been prepared in our laboratories, or proposed, are described.
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PMID:Extraction of artemisinin and artemisinic acid: preparation of artemether and new analogues. 805 18

Most malaria morbidity and mortality occurs in the community. Treatment aimed at managing patients at this level of the health care system should bring health and economic benefits to the population. Artemisinin suppositories have been successfully used in adults and children to treat, uncomplicated and complicated malaria. Their use early in the course of the disease may reduce complications and patient referral to tertiary care hospitals. A single dose of artemisinin followed by a single dose of mefloquine, given at the household or hamlet level, may be a therapeutic approach that has advantages for developing countries. However, widespread and uncontrolled use of artemisinin could result in unexpected and undesirable side-effects, improper dose schedules and poor compliance which, in turn, might cause primary treatment failures, recrudescences, and possibly resistance to the drug. Such problems can be avoided or managed by regulating and monitoring its use.
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PMID:Early treatment of malaria in the community using artemisinin--hope or hazard? 805 26


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