Amodiaquine less effective than chloroquine in the treatment of falciparum malaria in the Philippines

Amodiaquine was compared to chloroquine in two groups of Filipino patients with uncomplicated falciparum malaria. Every patient received 25 mg/kg of base orally given over three days. In a hospital study, all eight patients receiving chloroquine cleared their parasitemia by day 6, but six of eight patients receiving amodiaquine failed to clear parasitemia and in four patients there was no response at all (RIII resistance); this difference was significant (P less than 0.01). In a village based study, there was initial clearing of parasitemia in each patient. However, recrudescent infection occurred in all five patients receiving amodiaquine (RI resistance). Five of six falciparum infections were sensitive to chloroquine, while parasitemia reappeared in one patient. In this village, resistance to amodiaquine was significantly more common than resistance to chloroquine (P less than 0.05). To our knowledge, this is the first report of amodiaquine being substantially worse than chloroquine in the treatment of Plasmodium falciparum infection.     

The in-vitro susceptibilities of Ghanaian Plasmodium falciparum to antimalarial drugs

In Ghana in 2004 (when choroquine was still the nationally recommended drug for the first-line treatment of malaria), the sensitivities, to chloroquine, amodiaquine, quinine, mefloquine, artesunate and halofantrine, of 60 Plasmodium falciparum isolates from two ecologically distinct areas of the country were assessed in vitro. The aim was to make available, to policy-makers, the field-based evidence needed to review the national strategy for malaria treatment. Drug susceptibilities were explored using the standardized protocol of the Antimalarial Drug Resistance Network. Although 32 of the P. falciparum isolates evaluated (56.1% of the 57 isolates successfully investigated for their susceptibility to choroquine) showed resistance to chloroquine and two showed slightly reduced sensitivity to amodiaquine, all the isolates were sensitive to mefloquine, artesunate, quinine and halofantrine. The median inhibitory concentrations (IC(50)) of chloroquine were positively correlated with those of quinine (r=0.4528; P=0.0008) but not those of any of the other drugs investigated. The IC(50) of amodiaquine and artesunate were also positively correlated (r=0.3703; P=0.0067). These results provide evidence of the presence, in Ghana, of P. falciparum isolates that are highly resistant to chloroquine but generally sensitive to most of the other antimalarial drugs commonly used in the country. Partly in consequence of these observations, the recommended first-line treatment for malaria in Ghana was changed to an amodiaquine-artesunate combination in January 2005.     

Artemether treatment of recrudescent Plasmodium falciparum malaria in children

Summary Intramuscular artemether given for five days was evaluated prospectively in 32 patients with acute recrudescent Plasmodium falciparum malaria. All patients had experienced one or more treatment failures with one or more courses of the following drugs: chloroquine, amodiaquine, sulphadoxine-pyrimethamine and erythromycin given alone or in combination. There was a prompt response to treatment with fever and parasite clearance times of 10.7 (3.6) h (range 6–24) and 32.3 (8.3) h (range 24–48) respectively. Parasite reduction at 24 h was 93.2 (7.8)% (range 75–100). The cure rate on day 14 was 100%. The drug was well tolerated. These results suggest that artemether is rapidly effective in acute recrudescent Plasmodium falciparum malaria and is without deleterious side effects.     

Plasmodium falciparum in Madagascar: in vivo and in vitro sensitivity to seven drugs

The sensitivity level of Plasmodium falciparum isolates to chloroquine and the activity of six other antimalarials were studied in the different climatic zones of Madagascar in 1983. In vivo tests were done with 10 and 25 mg kg-1 of chloroquine and amodiaquine. Early recrudescence or RII resistance was observed after treatment with 10 mg kg-1 of these drugs in 34% of the cases for chloroquine and 6.5% for amodiaquine, and after the 25 mg kg-1 dose in 7% and 0% of the cases respectively. In vitro sensitivity of 84 P. falciparum isolates to seven drugs were studied with a semi-microtest. For chloroquine, 9% of the isolates had an IC50 above 250 nM, indicating resistance. In vitro activity of piperaquine was high for all isolates except two. In vitro activity of amodiaquine, dichlorquinazine, quinine, mefloquine and halofantrine was good against all isolates (maximum IC50 was 76, 92, 560, less than or equal to 20 and less than or equal to 12 nM, respectively). Correlation between the WHO standard field test and the in vitro semi-microtest was good. Resistance of P. falciparum to chloroquine was observed in the six survey areas, but the other tested drugs showed good activity. Since no cross-resistance to 4-aminoquinolines seems to exist in Madagascar, amodiaquine (the only one available at present) should be studied as an alternative to chloroquine in the prevention and treatment of falciparum malaria in this area.     

Molecular analysis of Plasmodium falciparum from drug treatment failure patients in Papua New Guinea

A study was conducted in Papua New Guinea to analyze Plasmodium falciparum drug resistance polymorphisms in patients presenting with resistant malaria. One hundred ninety-nine P. falciparum-positive patients were recruited at two sites, Madang and Maprik. Exposure to the 4-aminoquinolines chloroquine and amodiaquine was uniformly high, at 84% overall. However, 59% of these were taken in various combinations of sulfadoxine/pyrimethamine and/or primaquine and/or quinine. Two markers for 4-aminoquinoline resistance, P. falciparum chloroquine resistance transporter 76T and P. falciparum multidrug resistance 1, were fixed in the population and two markers for pyrimethamine resistance, dihydrofolate reductase (dhps) 59R and 108N, were found at moderate to high levels, overall 60% and 75%, respectively. No polymorphisms in dhps associated with sulfadoxine resistance were present. Differences between the two sites are analyzed. The study period encompasses a change in standard malaria treatment policy. These findings stress the need for regular monitoring of the effects of standard drug treatment of uncomplicated malaria in Papua New Guinea.     

Low efficacy of amodiaquine or chloroquine plus sulfadoxine-pyrimethamine against Plasmodium falciparum and P. vivax malaria in Papua New Guinea

Because of increasing resistance to 4-aminoquinolines in Papua New Guinea, combination therapy of amodiaquine (AQ) or chloroquine (CQ) plus sulfadoxine-pyrimethamine (SP) was introduced as first-line treatment against uncomplicated malaria in 2000. The purpose of this study was to monitor in vivo efficacy of the current standard combination therapy against Plasmodium falciparum and P. vivax malaria. Studies were conducted between 2003 and 2005 in the Simbu, East Sepik, and Madang Provinces in Papua New Guinea according to the revised protocol of the World Health Organization (WHO) for assessment of antimalarial drug efficacy. Children between six months and seven years of age with clinically overt and parasitologically confirmed P. falciparum or P. vivax malaria were treated according to the new policy guidelines (i.e., AQ plus SP given to patients weighing < 14 kg and CQ plus SP given to patients weighing < 14 kg). Children were monitored up to day 28 and classified according to clinical and parasitological outcome as adequate clinical and parasitological response (ACPR), early treatment failure (ETF), late clinical failure (LCF), or late parasitological failure (LPF). For P. falciparum malaria, polymerase chain reaction (PCR)-corrected treatment failure rates up to day 28 ranged between 10.3% and 28.8% for AQ plus SP and between 5.6% and 28.6% for CQ plus SP, depending on the region and the year of assessment. Overall treatment failure rate with AQ or CQ plus SP for P. vivax malaria was 12%. Our results suggest that the current first-line treatment in Papua New Guinea is not sufficiently effective. According to the new WHO guidelines for the treatment of malaria, a rate of parasitological resistance greater than 10% in the two dominant malaria species in the country justifies a change in treatment policy.     

Different patterns of pfcrt and pfmdr1 polymorphisms in P. falciparum isolates from Nigeria and Brazil: the potential role of antimalarial drug selection pressure

The effect of antimalarial drug selection on pfcrt and pfmdr1 polymorphisms in Plasmodium falciparum isolates from two distinct geographical locations was determined in 70 and 18 P. falciparum isolates from Nigeria and Brazil, respectively, using nested polymerase chain reaction and direct DNA sequencing approaches. All isolates from Brazil and 72% from Nigeria harbored the mutant SVMNT and CVIET pfcrt haplotype, respectively. The pfcrt CVMNT haplotype was also observed in (7%) of the Nigerian samples. One hundred percent (100%) and 54% of the parasites from Brazil and Nigeria, respectively, harbored wild-type pfmdr1Asn86. We provide first evidence of emergence of the CVMNT haplotype in West Africa. The high prevalence of pfcrt CVIET and SVMNT haplotypes in Nigeria and Brazil, respectively, is indicative of different selective pressure by chloroquine and amodiaquine. Continuous monitoring of pfcrt SVMNT haplotype is required in endemic areas of Africa, where artesunate-amodiaquine combination is used for treatment of acute uncomplicated malaria.     

Comparison of the relative in vitro activity of chloroquine and amodiaquine against chloroquine-sensitive strains of P. falciparum

The activities of chloroquine and amodiaquine against a sensitive strain of Plasmodium falciparum found in children in Ibadan were compared using an in vitro technique. The criterion for drug activity was the inhibition of maturation of the parasites. Three sets of experiments were performed with each of the two drugs. The minimum concentration of chloroquine causing 90% inhibition of maturation was 25 nmol as compared with 12 nmol for amodiaquine. This suggests a two-fold increase in activity of amodiaquine when compared with chloroquine against sensitive strains of P. falciparum. The implication is that amodiaquine is a much more potent tool in malaria chemotherapy than the erstwhile overused chloroquine.     

Molecular epidemiology of malaria in Cameroon. XXI. Baseline therapeutic efficacy of chloroquine, amodiaquine, and sulfadoxine-pyrimethamine monotherapies in children before national drug policy change

The availability of epidemiologic data on drug-resistant malaria based on a standardized clinical and parasitological protocol is a prerequisite for a rational therapeutic strategy to control malaria. As part of the surveillance program on the therapeutic efficacy of the first-line (chloroquine and amodiaquine) and second-line (sulfadoxine-pyrimethamine) drugs for the management of uncomplicated Plasmodium falciparum infections, non-randomized studies were conducted in symptomatic children aged less than 10 years according to the World Health Organization protocol (14-day follow-up period) at 12 sentinel sites in Cameroon between 1999 and 2004. Of 1,407 children enrolled in the studies, 460, 444, and 503 were treated with chloroquine, amodiaquine, or sulfadoxine-pyrimethamine, respectively. Chloroquine treatment resulted in high failure rates (proportion of early and late failures, 48.6%). Amodiaquine was effective at all study sites (proportion of failures, 7.3%). Sulfadoxine-pyrimethamine therapy was less effective than amodiaquine (P < 0.05), with failures observed in 9.9% of patients. Chloroquine is no longer a viable option and has been withdrawn from the official drug outlets in Cameroon. Amodiaquine and, to a lesser extent, sulfadoxine-pyrimethamine monotherapies are still effective in Cameroon, but further development of resistance to these drugs should be delayed by the novel strategy using artemisinin-based combination therapy. Our findings indicate that amodiaquine is the most rational partner for artesunate. Studies on the efficacy of artesunate-amodiaquine combination are currently being undertaken at several sites in the country.     

Plasmodium falciparum sensitivity to erythromycin and 4-aminoquinoline combinations in vitro.

Although erythromycin has been reported to be active against Plasmodium falciparum in vitro and P. berghei in vivo and in vitro when given alone or with chloroquine, it has been difficult to demonstrate a beneficial effect for the combination of erythromycin and chloroquine when used for the treatment of P. falciparum infections in humans. We developed a seven-day test of parasite sensitivity to a 4-aminoquinoline and erythromycin combination in vitro. Eight isolates of P. falciparum from the Kenyan coast were culture-adapted and exposed to erythromycin with chloroquine or with amodiaquine. The interaction of the drugs was evaluated by plotting the concentration of each drug needed to inhibit parasite growth. In seven isolates the combination of chloroquine and erythromycin was antagonistic; one isolate showed slight synergy The combination of amodiaquine and erythromycin was synergistic in three isolates but antagonistic in five. An antagonistic interaction may explain why erythromycin does not enhance chloroquine treatment of malaria in vivo in Kenya.     

Association between mutations in Plasmodium falciparum chloroquine resistance transporter and P. falciparum multidrug resistance 1 genes and in vivo amodiaquine resistance in P. falciparum malaria-infected children in Nigeria

This study investigated the association between Plasmodium falciparum chloroquine resistance transporter (pfcrt) T76 and P. falciparum multidrug resistance gene 1 (pfmdr1) Y86 alleles and in vivo amodiaquine (AQ) resistance, as well as the clearance of parasites harboring these two alleles in children treated with AQ in southwest Nigeria. One hundred one children with acute uncomplicated P. falciparum malaria infections were treated with the standard dosage of AQ and followed-up for 28 days. Blood samples were collected on filter paper samples at enrollment and during follow-up for identification of parasite genotypes and pfcrt and pfmdr1 mutations using polymerase chain reaction and restriction fragment length polymorphism approaches. Parasitologic assessment of response to treatment showed that 87% and 13% (RI) of patients were cured and failed treatment, respectively. Although infections in patients were polyclonal (as determined by merozoite surface protein 2 genotyping), the presence of both mutants pfcrtT76 and pfmdr1Y86 alleles in parasites is associated with in vivo AQ resistance (odds ratio = 7.58, 95% confidence interval = 1.58-36.25, P = 0.006) and is selected by the drug in children who failed AQ treatment. Treatment failure with the combination of mutant pfcrtT76 and pfmdr1Y86 alleles as well as the ability of patients to clear these resistant parasites is dependent on age, suggesting a critical role of host immunity in clearing AQ-resistant P. falciparum. The combination of mutant pfcrtT76 and pfmdr1Y86 alleles may be useful markers for monitoring the development and spread of AQ resistance, when combining this drug with other antimalarials for treatment of malaria in Africa.     

Sulfadoxine-pyrimethamine plus chloroquine or amodiaquine for uncomplicated falciparum malaria: a randomized, multisite trial to guide national policy in Uganda

The use of combinations of inexpensive drugs for the treatment of malaria in Africa has been proposed as an interim policy while awaiting the widespread availability of more effective regimens. We compared sulfadoxine-pyrimethamine plus chloroquine or amodiaquine in three districts in Uganda. Patients aged 6 months or greater with uncomplicated falciparum malaria were enrolled and randomized to therapy. Safety, tolerability, and efficacy outcomes, adjusted by genotyping, were assessed over 28 days. Of 1,105 patients enrolled, 1,057 (96%) completed follow-up. For children less than 5 years old, the risk of clinical treatment failure adjusted by genotyping at the three sites ranged from 34% to 67% with chloroquine plus sulfadoxine-pyrimethamine and from 13% to 35% with amodiaquine plus sulfadoxine-pyrimethamine (risk differences 21-32%, P < 0.0001 at all sites). Serious adverse events were uncommon with both regimens. The risk of treatment failure with chloroquine plus sulfadoxine-pyrimethamine, the current standard in Uganda, was unacceptably high. Amodiaquine plus sulfadoxine-pyrimethamine was significantly more efficacious; however, existing levels of resistance raises concern about the useful therapeutic life-span of this regimen.     

Chloroquine-resistant Plasmodium falciparum malaria confirmed by semi-micro sensitivity test for chloroquine seen in a person returned from Nigeria to Japan

A 39-year-old Japanese male engineer who stayed in Nigeria from August 17, 1987 through January 22, 1988, presented chloroquine-resistant Plasmodium falciparum malaria. He was taking oral chloroquine prophylactically. But he suffered from P. falciparum malaria in November, 1987 and early January, 1988. He was treated in Nigeria. After his return to Japan, he was admitted to our hospital with a fever of 39 degrees C on January 29, 1988. The peripheral blood smear on admission showed the presence of ring form P. falciparum. He was diagnosed as recrudescence of P. falciparum malaria. Laboratory examination revealed severe thrombocytopenia and biologic false-positive serological tests of syphilis. The level of 50% inhibitory concentration was 0.44 nmol/ml by in vitro chloroquine sensitivity test of the strain of P. falciparum obtained from this patient. Clinically, chloroquine was not effective. The patient was treated with intravenous quinine dihydrochloride followed by sulfadoxine/pyrimethamine tablets and recovered completely. As far as we know through our survey this patient was the first case of chloroquine-resistant P. falciparum malaria brought to Japan from Nigeria.     

Effects of chloroquine, amodiaquine and pyrimethamine-sulfadoxine on Plasmodium falciparum gametocytemia

The effects of chloroquine, amodiaquine and pyrimethamine-sulfadoxine (SP) (Fansidar) on the infection rate and density of Plasmodium falciparum gametocytes were studied in 198 patients with falciparum malaria from an area in the Punjab where malaria is endemic but seasonally transmitted. One month following treatment of 100 patients, SP had reduced the gametocyte carrier rate from 37% to 6% and the mean gametocyte density from 80 to 1.4 per mm3 of blood. Chloroquine and amodiaquine were much less effective. Since SP has no gametocytocidal properties and the reduction in gametocytes coincided with clearance of asexual parasitemias, gametocytes were probably reduced subsequent to the cure of the asexual malaria infections. If used during the nontransmission season, SP might be an effective component of an integrated program for reducing malaria transmission in the Punjab and other areas where 4-aminoquinoline-resistant and SP-sensitive falciparum malaria exists.     

Open randomized study of artesunate-amodiaquine vs. chloroquine-pyrimethamine-sulfadoxine for the treatment of uncomplicated Plasmodium falciparum malaria in Nigerian children

BACKGROUND: Artemisinin-based combination antimalarials are currently considered effective alternatives for the treatment of malaria in Africa, but there are few studies of such combinations in Nigerian children. We assessed the safety, treatment efficacy and effects on gametocyte carriage of the combination of artesunate plus amodiaquine and chloroquine plus pyrimethamine-sulfadoxine in children. METHODS: We evaluated 153 children who were aged 12 years or younger who had uncomplicated Plasmodium falciparum malaria. Patients were randomly assigned a combination of artesunate (4 mg/kg of body weight daily for 3 days) plus amodiaquine (30 mg/kg over 3 days), or chloroquine (25 mg/kg over 3 days) plus pyrimethamine-sulfadoxine (25 mg/kg of the sulfadoxine component at presentation). The primary endpoints were the proportions of children with adequate clinical and parasitological response, late parasitological failure, late clinical failure and early treatment failure. The parasitological cure rates on days 14-28 were also used as the primary endpoints. RESULTS: Both regimens were well tolerated; no child was withdrawn because of drug intolerance. All children treated with artesunate plus amodiaquine had adequate clinical and parasitological response (ACPR), while all but five children treated with chloroquine plus pyrimethamine-sulfadoxine had similar response. Fever clearance times were similar in the two treatment groups. However, the proportion of patients whose parasitaemia cleared by day 2 was significantly higher (100 vs. 50%, P = 0.00001) and parasite clearance was significantly faster (1.7 +/- 0.4 vs. 2.5 +/- 0.8 days, P = 0.0001) in children treated with artesunate plus amodiaquine. The cure rates on days 21 (100%vs. 94%, P = 0.03) and 28 (100%vs. 90%, P = 0.003) were also significantly higher in children treated with artesunate plus amodiaquine than in those treated with chloroquine plus pyrimethamine-sulfadoxine. Overall, a significantly higher proportion of children treated with chloroquine plus pyrimethamine-sulfadoxine carried gametocytes at least once during follow-up compared with those treated with artesunate plus amodiaquine [5 of 50 (10%) vs. 1 of 103 (0.97%), P = 0.01]. CONCLUSION: The combination of artesunate plus amodiaquine is therapeutically superior to a combination of chloroquine plus pyrimethamine-sulfadoxine, and significantly reduced gametocyte carriage following treatment.     

Efficacy of therapeutic combinations with artemisinin derivatives in the treatment of non complicated malaria in Burundi

Faced with the problem of resistance to chloroquine and sulfadoxine-pyrimethamine, the Ministry of Public Health of Burundi decided to study the efficacy of two artemisinin-based combinations, the fixed combination of artemether-lumefantrine and the combination of amodiaquine + artesunate. The efficacy of these combinations for the treatment of uncomplicated falciparum malaria was studied in two sites representative of the country, in Kigobe neighbourhood of Bujumbura, the capital city, and in Buhiga, a rural area. The study followed the standardized WHO protocol from October 2001 to November 2002. A total of 295 children under 5 years were included; 153 children were treated with artesunate and amodiaquine (77 at Buhiga and 76 at Kigobe), and 142 children with the combination of artemether-lumefantrine (64 at Buhiga and 78 at Kigobe). Among the 295 children, 290 were followed up to 14 days. In the group of 149 children treated with artesunate and amodiaquine, 142 (95.3%, 95% CI: 91.9-98.7%) presented with adequate clinical and parasitological response, five (3.3%) with late parasitological failure, one (0.7%) with late clinical failure and one (0.7%) with early treatment failure. Among the 141 children treated with artemether-lumefantrine, 140 (99.3%, 95% CI: 97.9-100%) presented with adequate clinical and parasitological response and one (0.7%) with late parasitological failure at Buhiga. Side-effects were comparable in both groups except for the vomiting. Vomiting was more frequent in the artesunate + amodiaquine on D1 and D2. Both treatments decreased the gametocyte carriage but without getting full clearance in all the patients. During a consensus workshop, the Ministry of Public Health agreed on the combination of artesunate and amodiaquine as the first line drug for the treatment of uncomplicated falciparum malaria in Burundi including epidemic outbreak.     

Sensitivity of Plasmodium falciparum to mefloquine-sulphadoxine-pyrimethamine (Fansimef) in vivo and to mefloquine alone in vitro in Nigeria

In Nigeria chloroquine remains the drug of choice for the treatment of falciparum malaria, since chloroquine resistance is not yet a problem. Nevertheless, in view of the rapid spread of multi-resistant Plasmodium falciparum in Africa it is desirable to test alternative drugs for efficacy and safety. To this end, we undertook a comparative controlled trial of the new triple combination, mefloquine-sulphadoxine-pyrimethamine (MSP, Fansimef) with chloroquine in a group of Nigerian children with symptomatic falciparum malaria. Our results showed that Fansimef was an effective blood schizontocide against the Nigerian strain of P. falciparum and was well tolerated. In particular, sinus bradycardia, which was frequently observed with Fanismef in the trials conducted in Zambia, was not seen in any of the Nigerian patients. In vitro sensitivity tests done on 26 P. falciparum isolates showed that all isolates were susceptible to complete inhibition by mefloquine, but the minimum concentration which produced complete inhibition in some isolates was higher than expected for fully sensitive parasites.     

Efficacy of artesunate plus amodiaquine, artesunate plus sulfadoxine-pyrimethamine, and chloroquine plus sulfadoxine-pyrimethamine in patients with uncomplicated Plasmodium falciparum in the Comoros Union

Health policy makers in Comoros Union have considered a policy change recommending combination treatment to control malaria. We evaluated the efficacy of three antimalarial drug combinations, taken orally, to enable the authorities to make an evidence-based choice. The study was carried out in patients of 2-70 years old in Moroni, Moheli and Anjouan in 2003. We enrolled 168 patients with uncomplicated malaria from 1097 outpatients screened at the health centres. One hundred and fifty-eight patients, of whom half were under five years old, (mean age=11.1+/-13.9 years), were followed up for 14 days. According to PCR adjusted outcome, the therapeutic efficacy of artesunate+amodiaquine (AS+AQ) (n=54) and artesunate+sulfadoxine-pyrimethamine (AS+SP) (n=53) was 100%, whereas that of chloroquine+sulfadoxine-pyrimethamine (CQ+SP) was 98% (50/51). The key difference between these treatments was the higher parasite clearance rate on Day 2 obtained with artesunate-containing combinations (P<0.001). These results provide a baseline for monitoring changes in the susceptibility of Plasmodium falciparum to artesunate+amodiaquine and artesunate+sulfadoxine-pyrimethamine (ACTs) in the Comoros Union. Health policy changes involving the replacement of chloroquine in the Indian Ocean subregion are discussed.     

Amodiaquine and sulfadoxine-pyrimethamine as treatment for chloroquine-resistant Plasmodium falciparum in Rwanda

The efficacy of amodiaquine and sulfadoxine-pyrimethamine combination as a second-line therapy for chloroquine-resistant Plasmodium falciparum infections was investigated in Rwanda in September 1986. Children less than or equal to 5 years old presenting with a P. falciparum parasitemia 14 days after treatment with chloroquine were administered either amodiaquine (25 mg/kg over 3 days, 64 patients) or sulfadoxine-pyrimethamine (as a single dose with tablets containing 500 mg of sulfadoxine and 25 mg of pyrimethamine: 1/4 tablet for children under 1 year, 1/2 for those 1-3 years old, and 1 tablet for those 4-5 years old; 34 patients) and followed for 7 days. Seven days after starting treatment with amodiaquine, 50 (76%) children were aparasitemic. All the children who had received sulfadoxine-pyrimethamine were aparasitemic 7 days after initiation of therapy.     

Evaluation of the relative efficacy of various antimalarial drugs in Nigerian children under five years of age suffering from acute uncomplicated falciparum malaria.

A parallel group-randomized comparison of the therapeutic efficacy of chloroquine (CQ), amodiaquine (AM), quinine (QN), sulphadoxine-pyrimethamine (S-P), mefloquine 15 mg kg-1 (M15) and mefloquine 25 mg kg-1 (M25) in acute symptomatic uncomplicated falciparum malaria was carried out in 325 children under the age of five years in Ibadan, southwestern Nigeria, using the 28-day in vivo test. The parasitological cure rate, assessed only up to day 14, was 85% in the CQ group and 100% in the other groups. The mean parasite and fever clearance times were, respectively, 2.64 and 1.20 days in the CQ-sensitive subgroup, 2.32 and 1.13 days in the AM group, 2.27 and 1.17 days in the QN group, 2.23 and 1.76 days in the S-P group, 2.13 and 1.10 days in the M15 group, and 2.07 and 1.09 days in the M25 group. The CQ-treatment failures (seven of 46 patients) were successfully treated with 25 mg kg-1 mefloquine, with parasite and fever clearance times of 1.73 and 1.0 days respectively. The study shows that, in Nigeria, CQ is now less effective than AM, S-P, QN and M in acute falciparum malaria in the group most vulnerable to the infection (the under-five-year-olds).(ABSTRACT TRUNCATED AT 250 WORDS)