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PubMed1992

In vitro sensitivity of Plasmodium falciparum to chloroquine and other antimalarials in east Timor and east Kalimantan, Indonesia.

In Indonesia resistance of Plasmodium falciparum to chloroquine has spread to all provinces except Yogyakarta since the first report in 1974. The proportion of resistant cases is relatively low except in Irian Jaya and East Timor. The results of in vitro tests performed in East Timor showed 81.0% resistance to chloroquine, 87.5% to amodiaquine, 20.0% to sulfadoxine-pyrimethamine (S-P), 4.8% to mefloquine, and 100% sensitivity to quinine. The percentage of failures was between 11.1% and 71.4% and highest with the S-P combination. Multidrug resistance was observed in 9 cases (or 11.1%). The results of in vitro tests in East Kalimantan were: 62.8% resistance to chloroquine, 100% to amodiaquine, 85.7% to S-P combination, 3.2% to quinine, and 2.5% to mefloquine. Failures rates ranged between 21.2% and 37.1% the highest being with mefloquine. Multidrug resistance was more prominent and observed in 59 cases (84.3%) of which one case was resistant to 5 antimalarials, while 4 cases (5.7%) were resistant to chloroquine only, compared to 72 cases (88.9%) in East Timor.

Adolescent↗
PubMed1992

Comparison of threshold and standard Amsler grid testing in patients with established antimalarial retinopathy.

To evaluate the sensitivity of threshold Amsler grid testing in the detection of established antimalarial retinopathy, 30 eyes of 15 patients with bilateral, irreversible field defects were examined with the standard Amsler grid and the threshold Amsler grid. Four eyes (13%) showed significant enlargement of large relative scotomas on testing with the threshold Amsler grid. Although only a small proportion of the eyes demonstrated an increase in the size of the scotoma, the patients had established field defects of varying depth, in some cases absolute scotomas. A prospective study in patients with early disease (i.e., with small, shallow scotomas) may be worth while.

Antimalarials↗
PubMed1962

Mass administration of an antimalarial drug combining 4-aminoquinoline and 8-aminoquinoline in Tanganyika.

For the eradication of malaria from hyperendemic regions of tropical Africa it is apparent that use may have to be made of antimalarial drugs, administered individually on a census basis, in addition to measures directed against the mosquito. The suppressive activity of existing compounds among individuals having different degrees of immunity is well established, and trials among large groups of people have been conducted with single drugs and with combination of drugs. In the large-scale trials carried out in Tanganyika and described in this paper, such a combination, containing amodiaquine for schizontocidal effect and primaquine as a gametocytocide, was administered to three distinct population groups of more than 5000 at differing intervals of time, in order to determine the ability of this combination to interfere with transmission in the absence of other malaria control measures. It was found that treatment of 93% of the population at intervals of one or two weeks resulted in a reduction of the malaria indices to a very low level but such success was not obtained when the combination of drugs was administered every four weeks, although in the area concerned population coverage was less satisfactory owing to migration.

Africa↗
PubMed1992

Antimalarial drug sensitivity patterns in the western province of Zambia. Implications for the management of primary health care (PHC).

The management of acute malaria consists of chemotherapy aimed at restoring the normal function of all organs. Appropriate treatment is dependent upon extensive knowledge of the drug sensitivity patterns of the malaria parasites in the area. This is also important for chemoprophylaxis. Drug sensitivity patterns and recrudescence rates for Mongu (Western Province in Zambia) are suggestive of a likely increase in resistance to both chloroquine and sulfadoxine-pyrimethamine (Fansidar). We found RI (19.4%), RII (1.5%) and RIII (4.4%) resistance to chloroquine and RII (4.3%) resistance to Fansidar. This calls for careful consideration of treatment schedules, legislation pertaining to the distribution of drugs in the general public and alternative antimalarial control strategies.

Adolescent↗
PubMed2003

[Drugs ototoxicity. Part II. Loop diuretics, nonsteroidal anti-inflammatory drugs, antineoplastic and antimalarial drugs ].

Ototoxicity has been recognized since the 1800, when it was learned that quinine and acetylsalicylic acid provoked dizziness, tinnitus and hearing loss. Beside above mentioned other drugs also have joined the list of ototoxic substances: aminoglycoside antibiotics, loop diuretics or antineoplastic drugs. In this review pharmacological and toxicological properties of potentially ototoxic drugs, such as loop diuretics, nonsteroidal anti-inflammatory drugs (salicylates), antineoplastic and antimalarial drugs are presented. Pathophysiology and postulated mechanisms causing drug-induced ototoxicity are also discussed.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed2004

A novel DNA-based microfluorimetric method to evaluate antimalarial drug activity.

This paper describes the development of a novel microfluorimetric assay to measure the inhibition of Plasmodium falciparum based on the detection of parasitic DNA by intercalation with PicoGreen. The method was used to determine parasite inhibition profiles and 50% inhibitory concentration values of known or potential antimalarial drugs. Values for parasite inhibition with known anti-malarial drugs using the PicoGreen assay were comparable with those determined by the standard method based upon the uptake of 3H-hypoxanthine and the Giemsa stain microscopic technique. The PicoGreen assay is rapid, sensitive, reproducible, easily interpreted, and ideally suited for screening of large numbers of samples for anti-malarial drug development.

Animals↗
PubMed2004

In vitro efficacy of antimalarial drugs against Plasmodium vivax on the western border of Thailand.

The susceptibility of 20 isolates of Plasmodium vivax on the Thailand-Myanmar border to seven antimalarial drugs was evaluated using the schizont maturation inhibition technique. The geometric mean 50% inhibition concentration (IC(50)) values were quinine = 308 ng/mL, amodiaquine =14 ng/mL, chloroquine =50 ng/mL, mefloquine = 127 ng/mL, sulfadoxine/pyrimethamine (80:1) = 800/10 ng/mL, pyrimethamine = 8 ng/mL, and artesunate = 0.5 ng/mL. Compared with P. falciparum in this area, P. vivax was more sensitive to chloroquine and artesunate, equally sensitive to quinine, and more resistant to mefloquine.

Animals↗
PubMed2004

[New methodologic approaches in antimalarial molecular research].

The estimated worldwide incidence of Plasmodium falciparum malaria is about 500 million cases a year. In tropical areas, the dramatic increase of resistance to most antimalarial drugs is directly responsible for persistent widespread high endemicity and related morbidity. The search to identify new drug targets and agents is a high priority. However the value of standard pharmacological research methods is greatly diminished by technical problems involving in vitro and in vivo modeling of malaria infection. In recent decades new mathematical tools have been developed to predict drug properties and to estimate biological activity in silico. Various approaches have been proposed based on 2D or 3D descriptions of the chemical structure of the drug and target followed by mathematical and statistical characterization of their interaction. These techniques are now widely used in medicinal chemistry and have proven their efficacy for screening the anti-malarial activity of numerous molecules in large databases and for virtual synthesis. Incorporating new knowledge from the genomic studies of Plasmodium has markedly increased the performance and range of application of these tools for identifying new drug targets against malaria.

Antimalarials↗
PubMed2004

Antimalarial drug resistance, artemisinin-based combination therapy, and the contribution of modeling to elucidating policy choices.

Increasing resistance of Plasmodium falciparum malaria to antimalarial drugs is posing a major threat to the global effort to "Roll Back Malaria". Chloroquine and sulfadoxine-pyrimethamine (SP) are being rendered increasingly ineffective, resulting in increasing morbidity, mortality, and economic and social costs. One strategy advocated for delaying the development of resistance to the remaining armory of effective drugs is the wide-scale deployment of artemisinin-based combination therapy. However, the cost of these combinations are higher than most of the currently used monotherapies and alternative non-artemisinin-based combinations. In addition, uncertainty about the actual impact in real-life settings has made them a controversial choice for first-line treatment. The difficulties in measuring the burden of drug resistance and predicting the impact of strategies aimed at its reduction are outlined, and a mathematical model is introduced that is being designed to address these issues and to clarify policy options.

Antimalarials↗
PubMedDate not supplied

[Parasitological resistance of Plasmodium falciparum to antimalarial drugs: what physicians should keep in mind].

Plasmodium falciparum drug resistance has considerably modified the attitude of physicians in terms of malaria case management. However, a bad understanding of the resistance phenomenon can lead to non-appropriate therapeutic and/or public health practices. The objective of this paper was to contribute to clarify the concept of parasitological resistance by analysing the different types of resistance observed in vivo. We showed through some examples that the precision of in vivo parasitological results depends on the type of microscopical technique used. We also showed that the classification system into resistance levels RI, RII, and RIII does not correspond to an increase in the resistance of the parasite itself but rather to an increase in the proportion of the resistant strains compared to the sensitive ones circulating in a given population. Mutant strains are circulating in low proportions as long as there is no selective drug pressure. They can be first detected in vitro and, later on, when their proportion increase, they are detected in vivo, first in non-immune subjects and later in semi-immune subjects. Therefore, the role of the host immunity is important in malaria drug resistance. To conclude, increasing use of antimalarial drugs (especially in monotherapy) cannot thwart the resistance, but rather leads to the selection of mutants strains. As the proportion of the mutant strains increases compared to the sensitive (wild) ones, it will reach the microscopic detection level and then, the clinical level. It is important that physicians involved in malaria case management understand these notions in order to avoid non-appropriate therapeutic decisions.

Animals↗
PubMed2004

The impact of age, temperature, and parasite density on treatment outcomes from antimalarial clinical trials in Kampala, Uganda.

Antimalarial drug treatment policy in sub-Saharan Africa is generally guided by the results of clinical drug efficacy studies in patients with uncomplicated Plasmodium falciparum malaria. The selection criteria used to enroll these patients often vary and may have a significant impact on treatment outcomes. In Kampala, Uganda, we investigated the impact of age, baseline temperature, and pre-treatment parasite density on estimates of treatment efficacy using a statistical modeling approach in 2,138 patients enrolled in six clinical trials involving seven different treatment regimens. Decreasing age, increasing temperature, and increasing parasite density were all independent predictors of an increased risk of treatment failure across all treatment groups. Compared with an unrestrictive approach to subject selection, enrolling only patients fulfilling selection criteria recommended by the World Health Organization (age < 5 years old, documented fever, and parasite density < 200,000/microL) increased the risk of treatment failure by 25-60% for the different treatment regimens. Caution should be taken when comparing results from drug efficacy studies with different subject selection criteria.

Age Factors↗
PubMed2004

Susceptibility of Leptospira serovars to antimalarial agents.

Leptospirosis has recently been described to cause concomitant infection with malaria. Only doxycycline has proven to have chemoprophylactic and therapeutic efficacy for both malaria and leptospirosis. To assess whether other traditional antimalarial agents have antileptospiral activity, we performed broth microdilution susceptibility testing of 16 Leptospira serovars (6 species/14 serogroups) to various agents. Artemisinin, atovaquone, chloroquine, mefloquine, primaquine, proguanil, pyrimethamine, sulfadoxine, quinine, quinidine, and combinations of atovaquone/proguanil and pyrimethamine/sulfadoxine all had a 90% minimum inhibitory concentration (MIC(90)) > 25 microg/mL (the upper limit of testing). The only agents identified with the potential to treat both infections other than doxycycline (MIC(90) = 1.56 microg/mL) were azithromycin (MIC(90) = 0.002 microg/mL) and clindamycin (MIC(90) = 0.2 microg/mL).

Antimalarials↗
PubMed2004

Adherence to antimalarial combination therapy with sulfadoxine-pyrimethamine and artesunate in rural Tanzania.

Artemisinin-containing antimalarial combination therapies are recommended to confront drug-resistant Plasmodium falciparum malaria. Among the questions surrounding whether these complex multidose treatments will be practical is to what extent patients complete the recommended doses. Combination therapy through coadministration of sulfadoxine-pyrimethamine plus artesunate was introduced as a first-line treatment for uncomplicated malaria in one district in Tanzania. Interventions to optimize correct use were also implemented. We observed 453 patient encounters at one health facility and recorded key practices as health workers dispensed the combination. A total of 253 patients were followed-up at 24 or 48 hours. Complete adherence measured at 48 hours reached 75.0%, based on self-report and tablet counts. This is substantially better than reported elsewhere and compares favorably with intervention studies to optimize adherence to chloroquine. Counseling about what to do if a patient vomits appears to have been an independent risk factor for nonadherence.

Adolescent↗
PubMed2003

Antimalarial drug resistance in the Eastern Mediterranean Region.

Studies done between 1997 and 2003 are reviewed to give an overall picture of antimalarial drug resistance in the Eastern Mediterranean Region of the World Health Organization (WHO). The situation in 8 countries where resistance has been reported is detailed. It has been difficult to abandon chloroquine as first-line treatment even though resistance to it is widespread. Resistance to sulfadoxine-pyrimethamine has also been detected. The spread of resistance could be slowed down by the adoption of effective national policies and control programmes. Coordination between counties and with other WHO regions, as opposed to working in isolation, could further reduce the spread of resistance.

Afghanistan↗
PubMed2005

[Case of drug-induced pneumonia possibly due to mefloquine (antimalarial drug)].

A 59-year-old man took mefloquine (antimalarial drug), total dose of 1,000 mg, to prevent malaria before and during traveling to South Africa. Three weeks after the first administration, he was admitted complaining of fever and dyspnea. Chest HRCT showed ground-glass opacities and consolidation in both lung fields. Withdrawal of mefloquine and treatment with corticosteroid resulted in improvement of the clinical findings. From the clinical course, we considered this case to be mefloquine-induced pneumonia. Mefloquine may have caused pulmonary toxicity.

Acute Disease↗
PubMed1992

An inexpensive and simple method for screening potential antimalarial drugs.

The visual in vitro test proved to be a very useful tool for screening a series of 54 chemical analogues for their antimalarial activity. The test relies on the formation of dark pigment precipitates after an alkaline solution is added to synchronous cultures of Plasmodium falciparum. Pigment is produced when a chemical compound is unable to prevent the maturation of rings to schizonts during incubation. However, in the presence of effective concentrations of a compound, maturation is inhibited and, consequently, pigment and precipitation are not observed. By using this procedure, 36 of the inactive or less active compounds could be excluded from assessment by the radioisotopic hypoxanthine incorporation test. This resulted in a substantial reduction in the overall cost of screening these compounds.

Animals↗
PubMed2005

Reduction of the efficacy of antifolate antimalarial therapy by folic acid supplementation.

Malaria and anemia are common conditions in patients presenting to outpatient clinics in Kenya. Anemia is usually due to malaria infection with underlying micronutrient deficiency. Iron therapy has been shown to enhance recovery from anemia in children with malaria, without affecting malaria treatment. Iron and folic acid are often prescribed together for anemic individuals. Until recently in Kenya, the drug of first choice for non-severe malaria was sulfadoxine-pyrimethamine (SP), an antifolate antimalarial drug. In this study, 303 patients of all ages with anemia and uncomplicated Plasmodium falciparum malaria attending an outpatient clinic in an area of seasonal malaria were treated with SP and iron, and were randomized to receive folic acid. Parasite clearance rates were measured using a survival analysis plot for both parasitologic and clinical failure. There was a significant reduction in the efficacy of SP in patients taking standard therapeutic doses of folic acid using the survival curve for parasitologic failure (P < 0.0001), but no difference for clinical failure (P = 0.7008). Folic acid supplementation did not enhance recovery from anemia.

Anemia↗