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In vitro effects of sulfadiazine and its metabolites alone and in combination with pyrimethamine on Toxoplasma gondii.

Sulfadiazine and the metabolites N4-acetyl-sulfadiazine, 4-OH-sulfadiazine, 5-OH-sulfadiazine, 5-OH-glucuronide-sulfadiazine, and 5-OH-sulfate-sulfadiazine were tested separately and in combination with pyrimethamine for the inhibitory activity on Toxoplasma gondii growth in vitro. Except for N4-acetyl-sulfadiazine, all sulfa compounds possessed anti-Toxoplasma activity. The addition of 0.05 micrograms of pyrimethamine per ml, a concentration which in itself is not inhibitory, potentiated the microbial activity of sulfadiazine and its metabolites 100 fold.

Animals↗

Risk of acute non-specific upper respiratory tract infections in healthy men taking dapsone-pyrimethamine for prophylaxis against malaria.

The relative risks of non-specific upper respiratory tract infections were studied in two well matched groups of military recruits to see whether dapsone-pyrimethamine (Maloprim) given as antimalarial prophylaxis was associated with immunosuppression. Mean risks of upper respiratory tract infection were 64% higher in the study group than in the controls, the largest monthly differences being recorded in the months of harder training. These findings were unlikely to have been due solely to harder training in the study group, as concurrently measured sprains (arguably more likely to have been affected) were increased by only 19%. A more likely explanation was some degree of immunosuppression, physical stress possibly having a synergistic effect. These findings suggest that travellers taking dapsone-pyrimethamine as antimalarial prophylaxis may be rendered more susceptible to commoner infections, especially when engaged in increased physical activity.

Acute Disease↗

Sulfadoxine specific lymphocyte transformation in a patient with eosinophilic pneumonia induced by sulfadoxine-pyrimethamine (Fansidar).

A patient developed eosinophilic peripheral pulmonary infiltrates while receiving malaria prophylaxis with sulfadoxine-pyrimethamine (Fansidar). Withdrawal of Fansidar and treatment with corticosteroids led to rapid recovery. No exacerbation occurred after cessation of corticosteroids. Lymphocyte transformation testing gave a positive result in the presence of sulfadoxine but not pyrimethamine. It is concluded that drug hypersensitivity to sulfadoxine was the cause of the eosinophilic pneumonia in this patient.

Adult↗

In utero treatment of toxoplasmic fetopathy with the combination pyrimethamine-sulfadiazine.

The mothers of 52 fetuses with toxoplasma fetopathy diagnosed in utero were treated with a combination pyrimethamine-sulfa drug and spiramycine. Their infants were compared to a group of 51 infants whose mothers had received spiramycine alone. Postnatal treatment was identical in both groups. Parasitological investigation of the placenta was positive in 42 and 76.6%; the newborns had a specific IgM of 17.4 and 69% in groups 1 and 2, respectively. These differences were significant. The mean specific IgG titer was significantly reduced at birth and at 4-6 months of age in group 1. According to the results obtained in the present material the pyrimethamine-sufa drug combination, given to the mothers of fetuses infected with toxoplasma, has a significant effect on the parasitological and serological signs of evolutive fetopathy. It did not significantly alter the clinical pattern, probably because the onset of treatment was too long after maternal infection.

Antibodies, Protozoan↗

Efficacies of chloroquine, sulfadoxine-pyrimethamine and quinine in the treatment of uncomplicated, Plasmodium falciparum malaria in eastern Sudan.

The efficacies of several antimalarial drugs in the treatment of uncomplicated Plasmodium falciparum malaria were compared, during an open, randomized trial, in New Halfa, eastern Sudan. The 96 patients who completed the 28 days of follow-up were treated with chloroquine (N = 26), sulfadoxine-pyrimethamine (N = 38) or quinine (N = 32). No treatment failures were observed among the patients given sulfadoxine-pyrimethamine. Only 23.1% of the patients given chloroquine showed adequate clinical response, however, the rest showing early (15.4%) or, more frequently, late (61.5%) treatment failure. In terms of parasitological failure, 54.1% of the patients given chloroquine showed early RI resistance, 7.7% showed late RI, and 15.1% showed RIII. Most (90.6%) of the patients treated with quinine had adequate treatment responses, the rest having late treatment failures (and late RI). The frequency of treatment failure was significantly higher, however, among the patients given chloroquine than in the quinine-treatment arm. The present results and those of earlier investigations indicate that the problem of chloroquine resistance is worsening in eastern Sudan, and that the use of chloroquine as the first-line drug for the treatment of uncomplicated malaria in this area is now compromised. The response to quinine may also be faltering.

Adolescent↗

Plasmodium falciparum malaria: rosettes are disrupted by quinine, artemisinin, mefloquine, primaquine, pyrimethamine, chloroquine and proguanil.

An assay was developed measuring the disruption of rosettes between Plasmodium falciparuminfected (trophozoites) and uninfected erythrocytes by the antimalarial drugs quinine, artemisinin mefloquine, primaquine, pyrimethamine, chloroquine and proguanil. At 4 hr incubation rosettes were disrupted by all the drugs in a dose dependent manner. Artemisinin and quinine were the most effective anti-malarials at disrupting rosettes at their therapeutic concentrations with South African RSA 14, 15, 17 and The Gambian FCR-3 P. falciparum strains. The least effective drugs were proguanil and chloroquine. A combination of artemisinin and mefloquine was more effective than each drug alone. The combinations of pyrimethamine or primaquine, with quinine disrupted more rosettes than quinine alone. Quinine may be an effective drug in the treatment of severe malaria because the drug efficiently reduces the number of rosettes.

Animals↗

Use of the Goettingen miniature pig for studying pyrimethamine teratogenesis.

Although pigs are suitable animals for experimental teratology, use of miniature pigs developed as a medicobiological experimental animal is essential for this purpose. Miniature pigs are established genetically so that the background data on the naturally occurring birth defects are reliable, whereas the commercial breeds are always improved genetically to seek higher productivity. In this review the authors summarized pyrimethamine teratogenesis in Goettingen miniature pigs. Pyrimethamine administration to a pregnant sow during the early stage of the organogenetic period caused cleft palate and other birth defects, and also hind leg paralysis, a functional defect in newborns.

Abnormalities, Drug-Induced↗

Submicroscopic Plasmodium falciparum infections before and after sulfadoxine-pyrimethamine and artesunate association treatment in Dienga, Southeastern Gabon.

BACKGROUND: It has been shown that Plasmodium falciparum submicroscopic infections (SMI) can contribute to malaria-associated anemia as well as to cerebral malaria. Polymerase chain reaction (PCR) assays are usually used as an alternative to microscopy in detecting subpatently infected individuals. OBJECTIVES: The main objective of this study was to investigate the occurrence of SMI before and after a suppressive antimalarial treatment in the population of the village of Dienga in Gabon. METHODS: Nested PCR was used to detect SMI and to determine genotypes. RESULTS: The prevalence rates of SMI were 13.67% (38/278) at day 0 and 8.99% (25/278) at day 14 after sulfadoxine-pyrimethamine-artesunate treatment. Genotype analysis of two polymorphic regions of the merozoite surface protein (MSP)-1 block 2, MSP-2 and a dimorphic region of the erythrocyte binding antigen (EBA-175) revealed that as many as 88% (22/25) of SMI detected after treatment were completely new alleles, indicating either previously sequestered parasites or newly acquired infections. CONCLUSION: These results demonstrate the usefulness of sulfadoxine-pyrimethamine-artesunate association treatment in the population of Dienga and confirmed early parasite genotype change after a suppressive antimalarial treatment in endemic areas.

Adolescent↗

Acetylator phenotype and response of individuals infected with a chloroquine-resistant strain of Plasmodium falciparum to sulfalene and pyrimethamine.

Acetylator phenotype was determined in 33 volunteers who were infected with a chloroquine-resistant strain of Plasmodium falciparum and who received, for cure, 2 g of sulfalene and 50 mg of pyrimethamine. This drug combination did not cure 5 of 14 rapid acetylators and 3 of 19 slow acetylators. This difference is not significant. Plasma levels of non-acetylated sulfalene, acetylated sulfalene, acetylation, and biologic half-life of non-acetylated sulfalene after administration of the combination did not differ importantly between the two groups. Acetylator phenotype does not appear to influence the response to sulfalene and pyrimethamine of individuals infected with chloroquine-resistant falciparum malaria.

Acetylation↗

Plasmodium falciparum and Plasmodium vivax infections in the owl monkey (Aotus trivirgatus). II. Responses to chloroquine, quinine, and pyrimethamine.

The studies described in this report were designed to determine the responses of established infections with eight strains of Plasmodium falciparum and two strains of P. vivax in owl monkeys to treatment with chloroquine, quinine, and pyrimethamine. Responses with these different strains ranged from cure via application of well-tolerated doses of two of the above drugs and refractoriness to treatment with maximally tolerated doses of the third, to complete resistance to maximally tolerated doses of all three compounds. The results of treatment exhibited in infected owl monkeys correlated well in two respects with those reported in humans infected with the same plasmodial species. First, calculated on a milligram per M2 basis, the doses of chloroquine, quinine, or pyrimethamine required for a CD90 response in owl monkeys infected with strains susceptible to these drugs were remarkably similar to the doses required and/or employed for cure of infections with so-called drug-susceptible strains in human patients. Secondly, with few exceptions, the responses to the above drugs in owl monkeys infected with the ten specially selected strains were essentially identical with those exhibited by human volunteers or patients infected with the same strains. Together, these findings and correlations provide strong support for use of owl monkeys infected with appropriate strains of P. falciparum and P. vivax in the search for more broadly effective antimalarial drugs.

Animals↗

Sulfadoxine-pyrimethamine for the treatment of acute malaria in children of Papua New Guinea. II. Plasmodium vivax.

In Papua New Guinea, Plasmodium falciparum and P. vivax are common causes of acute malaria in children and P. malariae an uncommon cause. The increasing prevelance of chloroquine-resistant strains of P. falciparum in Papua New Guinea has prompted the search for alternatives to chloroquine as standard presumptive treatment. Sulfadoxine-pyrimethamine, either alone or in combination with a single dose of chloroquine, was compared with chloroquine alone for treatment of acute vivax malaria in children in Madang. Fever resolution was slowest in the group treated with sulfadoxine-pyrimethamine alone, and time to clearance of parasitemia was significantly longer in this group (P less than 0.001). Where possible, species identification should be undertaken in acute malaria and cases of P. vivax treated with chloroquine.

Child↗

Severe cutaneous reactions among American travelers using pyrimethamine-sulfadoxine (Fansidar) for malaria prophylaxis.

In 1982, the fixed combination of pyrimethamine and sulfadoxine (Fansidar) became available in the United States, and was recommended for use in travelers at risk of acquiring chloroquine-resistant Plasmodium falciparum. Prior to that time, no reports of severe cutaneous reactions had appeared in the medical literature despite widespread use for more than 8 years in both Europe and malarious areas of the developing world. In the fall of 1984, the Centers for Disease Control received reports of 4 cases of toxic epidermal necrolysis (including 3 fatalities) among Americans who had used pyrimethamine-sulfadoxine (PYR/SDX) for the prevention of malaria. Subsequent investigation into severe cutaneous reactions associated with the use of this drug by American travelers detected 24 cases of erythema multiforme, Stevens-Johnson syndrome, or toxic epidermal necrolysis. Twenty-three of the 24 patients concurrently used chloroquine. Seven patients died. No risk factors in the development of these reactions other than the use of PYR/SDX could be identified. Among American travelers, we estimate that these reactions occur in 1 per 5,000-8,000 users, and that fatal reactions occur in 1 per 11,000-25,000 users. This higher than expected incidence necessitates that the use of PYR/SDX for the prevention of malaria be reconsidered. In the United States it is now recommended that the routine weekly use of the drug be reserved for those travelers at highest risk of acquiring chloroquine-resistant P. falciparum, when alternate prophylactic regimens are not deemed appropriate.

Adolescent↗

Response of Plasmodium falciparum infections to pyrimethamine-sulfadoxine in Thailand.

The results of this study in Thailand indicate that the early response of falciparum infections to a single dose of pyrimethamine-sulfadoxine is influenced by the developmental stages of the parasite present at the time of treatment. Parasite clearance is slower when young rings predominate at the time of treatment. This should be taken into account when considering the clinical management of patients and the comparative efficacy of antimalarials in clearing parasites from the peripheral blood. The 36-48 hr delay in schizonticidal action observed after treatment of febrile infections and the associated decline in blood concentrations of pyrimethamine suggest that a single dose may not be the ideal way of administering this drug combination and may encourage the emergence of drug-resistant parasites.

Adult↗

Pyrimethamine concentrations in serum during treatment of acute murine experimental toxoplasmosis.

Central nervous system toxoplasmosis is a major opportunistic infection in patients with acquired immunodeficiency syndrome. The standard therapy for this infection is pyrimethamine (PYR) and sulfonamides. To assess in vivo if PYR alone could adequately treat toxoplasmosis, a murine model of acute toxoplasmosis was used. The CD1 strain of mice was infected intraperitoneally with 10(4) parasites of the RH strain of Toxoplasma gondii. Pyrimethamine was administered in mouse chow at concentrations of 0, 0.03125, 0.0625, 0.125, 0.25, or 1.0 mg of PYR/g of food, which provides the following daily PYR dosages: 0, 6.25, 12.5, 25, 50, and 200 mg/kg/day. No sulfonamides were administered. Serum PYR levels proved more accurate than mg of PYR/g of food in predicting survival. Mice with serum PYR levels greater than or equal to 500 ng/ml (2 microM) survived and had no parasites present on peritoneal lavage. Mice with serum PYR levels less than 100 ng/ml (0.4 microM) had a 100% mortality rate and the average parasite count was 3 x 10(7) organisms in the lavage fluid. At a PYR level of 370 ng/ml, six of 11 mice survived and the lavage fluid contained 2.5 x 10(5) organisms. Previously, using 3H-uracil in an in vitro assay, PYR at a concentration of 500 ng/ml was shown to be as effective in inhibiting Toxoplasma growth as the combination of PYR (100 ng/ml) and sulfonamides 25 micrograms/ml). These data suggest the potential usefulness of PYR for monotherapy of toxoplasmosis and are consistent with previously described in vitro assays.

Acute Disease↗

Pyrimethamine-sulfadoxine efficacy and selection for mutations in Plasmodium falciparum dihydrofolate reductase and dihydropteroate synthase in Mali.

To assess pyrimethamine-sulfadoxine (PS) efficacy in Mali, and the role of mutations in Plasmodium falciparum dihydrofolate reductase (DHFR) and dihydropteroate synthase (DHPS) in in vivo PS resistance, 190 patients with uncomplicated P. falciparum malaria were treated with PS and monitored for 56 days. Mutation-specific polymerase chain reactions and digestion with restriction endonucleases were used to detect DHFR and DHPS mutations on filter paper blood samples from pretreatment and post-treatment infections. Only one case each of RI and RII level resistance and no cases of RIII resistance or therapeutic failure were observed. Post-PS treatment infections had significantly higher rates of DHFR mutations at codons 108 and 59. No significant selection for DHPS mutations was seen. Pyrimethamine-sulfadoxine is highly efficacious in Mali, and while the low level of resistance precludes assessing the utility of molecular assays for in vivo PS resistance, rapid selection of DHFR mutations supports their role in PS failure.

Animals↗

Treatment of Pneumocystis carinii pneumonia: current status of the regimens of pentamidine isethionate and pyrimethamine-sulfadiazine.

A randomized clinical trial is under way comparing the relative merits of pentamidine isethionate and pyrimethamine-sulfadiazine in the management of patients with Pneumocystis carinii pneumonia. Twenty-one patients have entered the trial. Both regimens have produced at least one complete recovery in biopsy-proved pneumocystis pneumonia. Two patients have died from pneumocystis pneumonia after being treated with a combination of both regimens. Initial observations on comparative toxicity indicate pentamidine isethionate has more local toxicity, but pyrimethamine-sulfadiazine is difficult to administer to severely ill patients. Comparative merits of the two regimens will be analyzed at the completion of the present clinical trial.

Administration, Oral↗

[Duration of action of the pyrimethamine-sulfametopyrazine combination in a Plasmodium falciparum endemic zone].

The duration of action of the drug Antemal, a combination of Pyrimethamine and Sulfametopyrazine, was eveluated in Bobo-Dioulasso, Upper Volta, West Africa, and endemic zone for Plasmodium falciparum malaria. The study was held during the season of maximum malaria transmission. 79 persons presenting with an acute attack of malaria were studied; 37 persons received a single dose of chloroquine sulfate (Nivaquine), at a dose of 15 mg./kg.; 42 persons received a single dose of Antemal at a dose of one tablet (75 mg. of Pyrimethamine and 25 mg. of Sulfametopyrazine) per 10 kg. Clinical and parasitological studies of all subjects occurred on days one, two, three, 10, 17, 24 and 31. Only one of 37 (2.7%) subjects on Antemal had a reappearance of trophozoites, occurring on day 17. Eight of 42 (19.0%) patients taking nivaquine had reappearance of trophozoites, observed between day 23 and 31. Gametocytes were observed in eight of 37 (21.6 %) persons on Antemal and in only one of 42 (2.3 %) persons on Nivaquine. These observations suggest an extended duration of protection from Antemal in semi-immune individuals. Nivaquine appeared as a potent inhibitor of gametocytogenesis.

Administration, Oral↗

Efficacy of Sulphadoxine and Pyrimethamine, Doxycycline and their combination in the treatment of chloroquine resistant Falciparum Malaria.

OBJECTIVE: The present in vivo study evaluates the efficacy of sulphadoxine/pyrimethamine, doxycycline and their combination in the treatment of Sudanese patients infected by chloroquine resistant falciparum malaria. METHODS: Febrile patients with positive blood smears of Plasmodium falciparum were given chloroquine 25mg-base/kg body weight and followed up for 3 days. Patients with recrudescence due to chloroquine resistance were readmitted for test treatment. Using simple number randomization patients were divided into groups, A, B and C. These were treated with doxycycline, sulphadoxine/ pyrimethamine and a combination therapy of sulphadoxine/pyrimethamine plus doxycycline. Doxycycline was initially administered as a single dose of 200mg followed by 100mg daily for 6 days whereas sulphadoxine/pyrimethamine was given as a single dose of sulphadoxine 1500mg and pyrimethamine 75mg. Patients of group C received the combination therapy of sulphadoxine/pyrimethamine and doxycycline. Clinical observations and examination of blood films were carried out for each patient daily for 6 days and thereafter weekly for 4 weeks. RESULTS: A high level of chloroquine resistance (75%) was documented amongst 280 patients (age 15-53 years) visiting Omdurman Hospital of Endemic Diseases during 1996-1998. The study demonstrated that only 46% and 78% of the patients were cured after 4 days of treatment by doxycycline and sulphadoxine/pyrimethamine. Patients treated with sulphadoxine/pyrimethamine in combination with doxycycline had a cure rate of 90% and 100% after 3-4 days of treatment, a single recrudescent case was detected on day 6. No relapses occurred during the follow up period. All patients were successfully treated by all regimens with the exception of one case treated by doxycycline. All treatments were well tolerated but a few cases had complaints of nausea. CONCLUSION: The combination therapy of doxycycline/sulphadoxine/pyrimethamine appeared to be significantly effective in the treatment of patients with chloroquine resistant falciparum malaria without causing any serious side effects. Such a combination regimen has the advantages of being available at a reasonable cost and less prone to development of resistance.

Antimalarials↗