Biomedical subjects
F Tin
Publications and source records attributed to F Tin.
Double-blind trial to find dose range using a fixed combination of mefloquine, sulfadoxine and pyrimethamine in falciparum malaria: a field study on adults in Burma.
In a field study conducted in Burma, 60 semi-immune adults were randomly assigned to 2 treatment groups. The first (mean parasite count, 12717/mm3) received a single dose of a fixed combination of 500 mg mefloquine base, 1000 mg sulfadoxine and 50 mg pyrimethamine (2 tablets of 'Fansimef') plus 1 tablet placebo. The second group (mean parasite count, 11 863/mm3) were given 3 tablets of the same medication. The study was double-blind. Parasite count was checked daily for the first week and weekly for a further 3 weeks. Average times for parasite clearance were 1.47 d in patients receiving 2 tablets, and 1.87 d in those given 3 tablets. Asexual parasites reappeared on day 28 in one patient in each group, although they had been free of parasites during the previous 4 weeks; this could be due to reinfection. The drugs were generally well tolerated, though mild and transient giddiness was seen in 80% of patients in the first group and 96% in the second. Nausea was reported by 33% and 43% of patients respectively. No vomiting occurred in the first group but 8 patients vomited in the second (P less than 0.01). In conclusion it seems possible to treat falciparum malaria in semi-immune adults, weighing less than 60 kg, with a single dose of 500 mg mefloquine base, 1000 mg sulfadoxine and 50 mg pyrimethamine (2 tablets), instead of the higher dose (3 tablets) currently recommended. This reduces treatment cost and improves tolerance of the drugs.
Falciparum malaria treated with a fixed combination of mefloquine, sulfadoxine and pyrimethamine: a field study in adults in Burma.
In a field study conducted in Burma, 54 semi-immune adults suffering from falciparum malaria (mean parasite count, 15 328/mm(3) before treatment) were given a single dose of a fixed combination of 750 mg mefloquine base, 1500 mg sulfadoxine, and 75 mg pyrimethamine (3 tablets of Fansimef). All these patients were cleared of asexual parasites by day 7, giving a cure rate of 100%; the mean clearance time was 2.6 days. Reappearance of parasitaemia occurred in 10 patients on or before day 7 and persisted for one day in 8 of them and for two days in 2 patients. It eventually disappeared without further treatment. No recrudescence occurred during the follow-up time of four weeks despite the fact that there was active transmission of Plasmodium falciparum in the area throughout the whole of the study period. The drug was generally well tolerated, though mild to moderate giddiness was reported by 49 patients (90.7%) and severe giddiness by 3 patients (5.5%). Nausea occurred in 25 patients (46.3%) and vomiting in 17 (31.5%).
Comparative drug trial of a sulfadoxine/pyrimethamine and a sulfalene/pyrimethamine combination against Plasmodium falciparum infections in semi-immune populations of Burma.
The antiplasmodial effect of a single dose treatment with a sulfadoxine/pyrimethamine combination as compared to a sulfalene/pyrimethamine combination against falciparum malaria was assessed in semi-immune populations in Burma in early 1980. Parasite clearance rates on Day 7 after treatment were 99.2% for the sulfadoxine/pyrimethamine combination and 98.6% for the sulfalene/pyrimethamine combination for all age-groups. The earlier recrudescence rates within one month were 3.7% and 9.2% respectively, while the later recrudescence rates between 1 and 2 months were 9% and 8.3% respectively. Hence, both combinations were equally effective for treatment of falciparum malaria as no significant difference in the parasite clearance rates was observed. However, the earlier recrudescence rates showed a significant difference with a higher rate for the sulfalene/pyrimethamine combination. This is thought to be due to the shorter half-life of sulfalene compared to sulfadoxine and to its being unable therefore to suppress the falciparum infections for as long a period as sulfadoxine. But there was not much difference in the later recrudescence rates. These combinations have a stimulating effect on the production of falciparum gametocytes; and, in order to minimize transmission, an effective gametocytocide such as primaquine should be given along with them, as well as with the chloroquine/pyrimethamine combination, in areas with efficient malaria vectors. Recrudescence rates and gametocyte rates were highest among children in the 1-4 years age-group and this could be attributed to their lower level of acquired immunity compared to the older children and adults. Vivax malaria was also found to be effectively suppressed for about 4 weeks with both combinations.(ABSTRACT TRUNCATED AT 400 WORDS)
Single-dose treatment of falciparum malaria with mefloquine: field studies with different doses in semi-immune adults and children in Burma.
Different doses of mefloquine (20 and 30 mg/kg of body weight in children, and 750 and 1000 mg in adults) were tested in controlled clinical trials in 89 children and 60 adults who were semi-immune carriers of Plasmodium falciparum. There was no significant difference in the efficacy of the two doses, either in the children or in the adults. An RI-type resistance was found in 1 adult, when recrudescence occurred on day 7, and in 4 children, who showed recrudescence on day 14. In all 5 patients, spontaneous disappearance of parasites was observed at further parasitological checks, thus indicating that mefloquine has a prolonged action. One patient who vomited after taking the drug was successfully retreated with mefloquine on day 14.Nausea, giddiness, and vomiting are the three symptoms most frequently attributed to mefloquine. The incidence of nausea and giddiness was similar in both dosage groups, but the adults in the higher dosage group had a significantly higher frequency of vomiting than those in the low-dose group.In view of the rapid and reliable action of a single dose, mefloquine seems to be the drug of choice for treatment of cases of falciparum malaria that are resistant to 4-aminoquinolines and to sulfonamide-pyrimethamine combinations. A dose of 20 mg per kg of body weight for children and 750 mg for adults is sufficient for treatment of semi-immune persons.
Resistance to antimalarials by Plasmodium falciparum in Burma.
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Serological responses to Plasmodium and Toxoplasma in school children from two areas in Burma.
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Chloroquine-resistant malaria in Burma.
Two field trials to detect chloroquine-resistant malaria were conducted according to WHO recommendations in a malaria free area near Rangoon. Peripheral blood smears were examined for asexual forms of P. falciparum on day one through to day seven, on day 14, 21, and 28 after a standard dose of 1500 mg. of chloroquine base. Haskins test to detect chloroquine in urine was done on all cases and plasma chloroquine levels were measured in some. Out of 105 patients tested RI resistance was detected in 66, RII in 19 and RIII in three. Subsequent trials with other anti-malarial drugs indicated that the chloroquine-resistant P. falciparum were also resistant to one day therapy with pyrimethamine 50 mg. or sulphamethoxypyridazine 1 G given singly; and resistant to one day therapy with combinations of pyrimethamine 50 mg. plus sulphamethoxy pyridazine 1 G, pyrimethamine 13 mg. plus dapsone 100 mg., and trimethoprim 320 mg. plus sulphamethoxazole 1600 mg. All those tested were sensitive to quinine sulphate, 0-6 G given three times a day for 10 days, and were also sensitive to one day therapy with combinations of trimethoprim 500 mg. plus sulphalene 1 G, and pyrimethamine 50 mg. plus sulphamethoxine 1 G. Pyrimethamine 12-5 mg. plus dapsone 100 mg. in weekly doses was shown to be an effective chemoprophylaxis. Quinine was tested on 38 subjects while other drug schedule were tested on six to eight subjects.
Resistance to chloroquine of Plasmodium falciparum from Burma.
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