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

Each year at least 30 000 Western travellers acquire malaria and approximately 1-4% of those who acquire Plasmodium falciparum malaria will die as a result of infection. Almost all cases and fatalities are preventable with the use of measures to reduce mosquito bites and appropriate chemoprophylaxis for those at high risk of infection. There are currently a limited number of licensed drugs available to prevent malaria in travellers. New effective and well tolerated agents are urgently needed because of increasing resistance to antimalarials such as chloroquine and proguanil, and real and perceived intolerance to standard drugs such as mefloquine. A newly licensed antimalarial (atovaquone plus proguanil; Malarone) compares favourably with other drug options, although some prescribers may be unfamiliar with the specific advantages and disadvantages of this antimalarial. This article reviews recent clinical experience and randomised controlled trial data in order to address frequently asked questions about this new combination drug.
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PMID:Current status and replies to frequently posed questions on atovaquone plus proguanil (Malarone) for the prevention of malaria. 1278 75

Clinical treatment failures of the hydroxynaphthoquinone atovaquone or its combination with proguanil (Malarone) in Plasmodium falciparum malaria has been recently documented. These events have been associated to single nucleotide polymorphisms (SNPs) in the parasite cytochrome b gene (cytb). In this report we describe a set of nest PCR-RFLP methods developed for the fast detection of all known cytb mutations associated to resistance to these drugs. The methods were successfully applied for the analysis of phenol-chloroform extracted DNA samples from patients not cured by Malarone, and from an established parasite clone. Further, the protocol for the detection of the A803C mutation was applied to 164 DNA field samples extracted through crude methanol-based protocols, originated from several malaria settings. The PCR-RFLP methods here presented can be used as a valuable for the clinical detection and study of Malarone and atovaquone P. falciparum resistance.
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PMID:Detection of atovaquone and Malarone resistance conferring mutations in Plasmodium falciparum cytochrome b gene (cytb). 1278 29

To the best of our knowledge, Stevens-Johnson syndrome (SJS) has not been reported previously as an adverse reaction to Malarone, which is a combination of atovaquone and proguanil hydrochloride used for antimalarial prophylaxis and therapy. We describe a 65-year-old patient who had SJS with typical clinical and histopathological findings associated with the use of Malarone prophylaxis for malaria. This report should alert physicians to this severe cutaneous reaction, and Malarone should be added to the list of drugs that can potentially cause SJS.
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PMID:Stevens-Johnson syndrome associated with Malarone antimalarial prophylaxis. 1283 Apr 30

Most cases of malaria in the United States, including the case described below, are due to travelers not taking proper prophylactic medications. With a potentially long incubation period, patients are frequently misdiagnosed (often with viral syndrome or pharyngitis) and correct treatment is delayed. Effective preventative medicines include Malarone, mefloquine, and doxycycline. Chloroquine, a staple of malaria prevention in the past, now has very limited usefulness due to drug resistance.
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PMID:Malaria: a case report in Oklahoma and a review of prophylaxis for travelers. 1295 76

Malarone, a fixed combination of atovaquone with proguanil (AP), has recently been recognized as a promising treatment against multidrug-resistant Plasmodium falciparum. In Vietnam, the first-line treatment for P. falciparum malaria is currently a combination of mefloquine and an artemisinin derivative, and the use of AP has not been explored. The aim of the present study, based in Vietnam, was to assess the efficacy of AP when used to treat P. falciparum recrudescences that had occurred after primary treatment with mefloquine-artesunate. All but two of the 39 patients investigated completed follow-up. The mean parasite- and fever-clearance times [and 95% confidence intervals (CI)] after AP treatment were 36 (30-42) and 21 (18-24) h, respectively. Most (32) of the 37 infections that were followed adequately appeared to be eradicated by the AP, the other five recrudescing once more. The overall cure 'rate' and (CI) was 86% (76%-98%). All of the patients tolerated the AP well. Atovaquone-proguanil appears to be a safe and promising alternative treatment for P. falciparum infections in South-east Asia, although the combination is relatively expensive and may not clear some infections with multidrug-resistant parasites.
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PMID:Atovaquone-proguanil for recrudescent Plasmodium falciparum in Vietnam. 1451 55

Malarone (atovaquone-proguanil) is an effective drug for the treatment and prophylaxis of multidrug-resistant falciparum malaria. However, first cases of resistance have been reported, which are associated with mutations at codon 268 of the parasite's cytochrome b gene. We report the first case of Malarone treatment failure from Central Africa.Drug concentration was well within curative range. Pre- and post-treatment Plasmodium falciparum isolates revealed codon 268 wild-type alleles, and no other mutations of the putative atovaquone-binding domain.These findings illustrate the spread of atovaquone-proguanil-resistance in Africa and question the usefulness of codon 268 as the only target for the surveillance of its emergence.
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PMID:Malarone treatment failure not associated with previously described mutations in the cytochrome b gene. 1518 99

Whereas parasitic diseases are always a heavy burden for humanity, few are the new antiparasitic molecules marketed during the last 25 years. Thus on the 1393 new molecules marketed between 1975 and 1999, only 7 have antiprotozoan properties. This talk will detail the progress made in the treatment of the intestinal protozoa, malaria, visceral leishmaniasis and toxoplasmosis, problems with which are especially confronted the European parasitologists. The treatment of Giardia and intestinal amoebas is based on 5-nitro-imidazoles derivatives. Single-dose treatments can be used with tinidazole or secnidazole. Resistance to these compounds of Giardia were described and in these cases, treatment by quinacrine or nitazoxanide are possible alternatives. Nitazoxanide is marketed in the United States and in Australia. It seems to be a well tolerated antiparasitic agent with a broad spectrum because it is active on a lot of intestinal protozoa and helminths. It acts on the same metabolic way as the 5-nitro-imidazoles (inhibition of the ferredoxine reductase) but without synthesis of free radicals and DNA deterioration of the target cell. It is thus neither teratogenic nor mutagenic. Artemisinin derivatives allowed considerable progress in the treatment of malaria. They have short half-lifes, allowing a fast parasitic clearance and these derivatives do no provoke resistance. They are first line drugs for the treatment of malaria in areas of drug resistance. The arthemeter-lumefantrine association (Riamet, Coartem) ensures a rapid disappearance of the circulating parasites and is well tolerated. Atovaquone-proguanil (Malarone) is usable in the treatment of acute malaria but also in disease prevention with the advantage of continuing drug intake for only 7 days after having left the infected area. The treatment of leishmaniasis is always delicate and is characterized by the worrying development of antimony resistances, probably related in the European zones to the treatment of dogs. Liposomal amphotricin is an alternative of choice but remains very expensive. The heating of amphotericin to 70 degrees C during 20 minutes gives it experimental properties and efficacies comparable with that of liposomal amphotericin, but at a less cost. Miltefosine, an alkyl-phospholipide antimetabolite, is very active on visceral leishmaniasis resistant to antimonial treatment. However, its long half-life could induce the emergence of resistances. Miltefosine induces much less side effects than conventional amphotericin B. The commonly used anti-toxoplasmic drugs (sulphadiazine and pyrimethamine) were marketed some 50 years ago and are only active on the rapid forms in multiplication. No drug is really efficient on the cysts although preliminary tests with atovaquone are encouraging to treat ophthalmologic forms in immunocompetent patients. To conclude, it is important to continue to search for new antiprotozoan molecules because, for some parasites, drug resistance is an important problem. Moreover, the treatment of the pregnant women, particularly during the first trimester, is often impossible and there is a lack of galenic forms easily usable in children. A better knowledge of the metabolic pathways of protozoa (particularly the apicoplast of Apicomplexa parasites) would certainly open the posssibility to identify new drugs. To reduce and delay the appearance of resistances, mass-treatments of mass should be avoided and targeted treatments prefered as well as the use of associations of molecules having different modes of action.
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PMID:[New drugs for the treatment of human parasitic protozoa]. 1530 92

Malaria chemoprophylaxis concerns prescribing healthy individuals medication for an infection they have an unknown chance of getting. Sensible use of malaria chemoprophylaxis is a balance between the risk of infection and death, and the risk of side effects. The risk of infection can be broken down into the risk of being bitten by a malaria-infected mosquito and the risk of the malaria parasites being resistant to the drug used for prophylaxis. Our knowledge of these parameters is patchy. The risk of infection is not uniform at a given location and the standard of living will greatly influence risk. It is suggested that chemoprophylaxis should not be recommended in areas with less than ten reported cases of P. falciparum malaria per 1000 inhabitants per year. The resistance pattern is known to a certain extent but, for instance, diverging opinion of how much resistance to chloroquine there is in West Africa illustrates the lack of data. There is much debate on rare adverse events, which usually escape Phase III studies prior to registration and are only picked up by passive, postmarketing surveillance. The lessons over the past 20 years with the introduction of amodiaquine, pyrimethamine/dapsone (Maloprim, GlaxoSmithKline) and pyrimethamine/sulfadoxine (Fansidar, Roche), which were all withdrawn for prophylaxis after a few years, show how sensitive drugs for chemoprophylaxis are to side effects. Three levels of chemoprophylaxis are used: chloroquine in areas with sensitive P. falciparum, chloroquine plus proguanil in areas with low level chloroquine resistance, and atovaquone/proguanil (Malarone, GlaxoSmithKline), doxycycline or mefloquine (Lariam, Roche) in areas with extensive resistance against chloroquine and proguanil. Primaquine and the primaquone analog tafenoquine may be future alternatives but otherwise there are few new drugs for chemoprophylaxis on the horizon.
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PMID:Malaria chemoprophylaxis: when should we use it and what are the options? 1548 77

The treatment of patients with severe malaria in sub-Saharan Africa has become a challenge to clinicians due to poor compliance to quinine and the increasing multidrug resistance to antimalarials by the P. falciparum parasite. The aim of this study was to compare the efficacy and safety profile of two truncated antimalarial regimens of intravenous quinine followed by oral Malarone (Malarone arm) with intravenous quinine followed by oral quinine (quinine arm) in the treatment of severe P. falciparum malaria. The outcome measures were parasite clearance time, fever clearance time, efficacy, and adverse events profile. Consecutive patients aged 1-60 years, with a diagnosis of severe malaria with positive blood smears for P. falciparum parasites and admitted to the Moi Teaching and Referral Hospital were randomized into the two study arms. Of the 360 patients studied 167 and 193 cases were randomized into the Malarone and quinine arms, respectively. Of the five (1.4 per cent) patients who died, three came from the quinine arm. The frequency of adverse reactions was higher in the oral quinine group (31.6 per cent) than in the Malarone group (25.7 per cent). The mean parasite clearance time was 120 h and 108 h for the quinine and Malarone arms of the study, respectively, and the mean fever clearance times were 84 h and 72 h for the quinine and Malarone arms, respectively (p=0.1). Truncated therapeutic regimen using malarone after intravenous quinine is safer and as effective as conventional intravenous quinine followed by oral quinine in the treatment of severe malaria. The P. falciparum recrudescence rate was lower with the use of Malarone than for quinine.
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PMID:A randomized open label clinical trial to compare the efficacy and safety of intravenous quinine followed by oral malarone vs. intravenous quinine followed by oral quinine in the treatment of severe malaria. 1560 53

In France, 4,000 imported malaria cases are reported each year (7,000 to 8,000 estimated). Chemoprophylaxis is essential for prevention in travelers. When malaria is susceptible to chloroquine, this drug (Nivaquine) has to be used. It is given daily in France (1.5 mg/kg per day), from departure to four weeks after return. When low levels of chloroquino-resistance are reported, French authorities recommend the use of chloroquine + proguanil (Savarine) if the body weight is >50 kg or Nivaquine) + Paludrine), if <50 kg), or atovaquone + proguanil (Malarone). Nivaquine) (1.5 mg/kg per day) and Paludrine) (3 mg/kg per day) have to be pursued for one month after return, although Malarone) (1 pediatric tablet/10 kg per day, in children >10 kg weight) may be disrupted after one single week. Adverse events are rarer with atovaquone + proguanil, than with chloroquine + proguanil. When chloroquino-resistance is high, Malarone) or mefloquine (Lariam) are used. Weekly drug regimen is recommended with mefloquine (5 mg/kg per weight) for the travel duration and four weeks after return and the drug tolerance is good in pediatric prophylaxis. Doxycycline is used under conditions in children >8 years of age. New drugs as for tafenoquine, an amino-8 quinoleine, might enhance patients compliance if given monthly.
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PMID:[Malaria chemoprophylaxis in traveling children]. 1565 56


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