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At least 19 recordsLinked to original sources
PubMed1977

Praziquantel, a new board-spectrum antischistosomal agent.

Praziquantel, (2-cyclohexylcarbonyl)-1,2,3,6,7,11b-hexa-hydro-2H pyrazino[2,1a]isoquinolin-4-one, belongs to a new series of antischistosomal compounds. The results of a detailed study of the efficacy of praziquantel on Schistosoma mansoni in mice, Mastomys and Syrian hamsters are described. Praziquantel is effective after oral and all parenteral routes of administration tested. The amount of praziquantel required to achieve parasite reductions of at least 95% depends on the host species and on the routes and schedules of administration. Total doses range from 200--1,000 mg/kg in mice and from 100--500 mg/kg for Mastomys and hamsters. In all three species, splitting of the total dose into 3 or more fractional doses given within 1 day approximately doubles the efficacy over that achieved after a single oral administration of the same total dose. A single subcutaneous dose is only slightly more effective, whilst a single intramuscular injection in olive oil is about twice as effective as a single oral administration. Praziquantel is very effective against the invading stages and slightly less against schistosomules up to an age of 7 days. It is less effective against 2- to 4-week-old juveniles, but is effective again against 5-week-old and older schistosomes. Praziquantel is equally effective against both sexes of S. mansoni. It is less effective against unpaired and therefore juvenile female worms, but fully effective against single male worms. The efficacy of praziquantel on S. mansoni in mice is not influenced by the strain or the sex of the host, the worm burden or the age of the infection. Considering all data available, praziquantel promises to be a very potent antischistosomal drug.

Animals↗
PubMed1979

The effect of praziquantel on Hymenolepis diminuta in vitro.

Qualitative observations were made on Hymenolepis diminuta, H. microstoma, H. nana and pre-adult Echinococcus multilocularis in vitro. A dose as low as 0.0001 microgram praziquantel/ml affects the tapeworms, while concentrations of 0.01 - 0.1 and 1-10 microgram/ml cause contraction and paralysis in the contracted state within 10 min and 10-30 s, respectively. The in vitro effects of praziquantel on Hymenolepis diminuta have been studied using anaerobic and aerobic incubations and media containing or lacking glucose. Praziquantel inhibits glucose up-take by half at a concentration of 0.1 microgram/ml, both under anaerobic and aerobic conditions. The stimulation of lactate release was most marked in the absence of glucose. A doubling of the amount of lactate released during anaerobic incubation in the presence of glucose was achieved in 0.1 microgram/ml, while 0.01 microgram/ml had the same effect in the absence of glucose. Under aerobic conditions and in the absence of glucose, 0.1 microgram/ml doubled the amount of lactate released while 3 and 10 microgram/ml were without effect in the presence of glucose. Praziquantel increases the total amount of excreted acidic metabolites only in the absence of glucose. The oxygen consumption of H. diminuta was unaffected by praziquantel at a concentration of 10 microgram/ml. Worms treated in their host and then incubated display the same changes as worms treated in vitro. Praziquantel causes an efflux of glucose and alpha-amino-N from the worm into the medium. This impairment of tegumental integrity and the inhibition of glucose up-take and the stimulation of lactate release are reversible after a 15 min incubation in praziquantel solution. Discussion of pharmacokinetic data indicates, that in the in vivo situation, effective concentrations of praziquantel prevail for much longer. Mechanisms that might explain the observed effects are discussed.

Aerobiosis↗
PubMed1977

[The efficacy of mebendazole and praziquantel on larval taeniids from mouse, rabbit and pig (author's transl)].

The efficacy of Mebendazole (Janssen) and Praziquantel (Bayer) on Cysticercus fasciolaris, C. tenuicollis resp. C. pisiformis was studied in 125 mice, 63 pigs and 30 rabbits. All mice were infected naturally with C. fasciolaris. The pigs were infected experimentally with 2000 resp. 5000 eggs of Taenia hydatigena and the rabbits with 1500 eggs of Taenia pisiformis. 8 weeks p.i. animals were divided into groups and received 25 mg/kg Mebendazole or 50 mg/kg Praziquantel on 5 consecutive days as well as 5 mg/kg Mebandazole resp. 10 mg/kg praziquantel for 14 days. The applied doses of 62.5 and 12.5 mg/kg Mebendazole to mice for 10 days or 14 days showed almost no efficacy against C. fasciolaris whereas 250 and 125 mg/kg Praziquantel given for 10 days gave 100% good results. We found that Mebendazole is highly efficient only against C. tenuicollis at a concentration of 25 mg/kg in the pig, whereas in the rabbit the 5 mg dose over 14 days still revealed good results. Praziquantel showed a virtually 100% success using 50 mg/kg for 5 days and 10 mg/kg for 14 days, whereas the efficacy of Praziquantel against C. pisiformis in rabbits administering the same dose was not satisfying.

Animals↗
PubMed1979

Double-blind studies of tolerance to praziquantel in Japanese patients with Schistosoma japonicum infections.

The first clinical trials of praziquantel against Schistosoma japonicum infections in Japan were planned to assess tolerance only. Three double-blind studies against placebo involving a total of 51 patients were conducted with dosages of praziquantel of 1 x 20 mg/kg body weight, 2 x 20 mg/kg, 3 x 20 mg/kg given on one day.The frequency of unwanted side effects was higher in the group of patients given praziquantel at a dose of 3 x 20 mg/kg than in all other drug- or placebo-treated patients. In general, the side effects, which included drowsiness, headache, lumbago, abdominal fullness, or epigastric discomfort, lasted for several hours but disappeared spontaneously. The results of laboratory tests showed no significant changes caused by treatment.The overall assessment showed excellent or good tolerance in all patients treated with praziquantel at the lower dose levels. In those given 3 x 20 mg/kg, tolerance was excellent in 1 of 12 patients, good in 9, and fair in 2, whereas the respective placebo-treated group showed excellent tolerance in 3 of 12, good in 7, and fair in 2.

Adult↗
PubMed1979

The effect of praziquantel on Schistosoma mansoni.

3 x 10(-6)M praziquantel fails to completely paralyse miracidia and cercariae in a short time but they are not infective when maintained in the solution. 3 x 10(-5)M praziquantel prevents infected snails shedding cercariae but does not kill daughter sporocyts or developing cercariae. As the action of praziquantel on adult worms is not blocked by 10(-2)M mecamylamine, pempidine or carbachol, but is reduced by calcium depletion, it is suggested that praziquantel may act by permitting calcium influx to muscle cells causing them to contract.

Animals↗
PubMed1978

The efficacy of praziquantel against cestodes in cats, dogs and sheep.

Praziquantel is a new type of acylated isoquinoline-pyrazine. A single, low oral or subcutaneous dose of the compound is reliably effective against all tested juvenile and adult cestodes in cats, dogs and sheep. Praziquantel is the first cestodicide which is also effective on bile duct cestodes. In cats and dogs, 5 mg praziquantel per kg is completely effective on all stages of Taenia hydatigena, T pisiformis, T ovis, T taeniaeformis, Dipylidium caninum, Mesocestoides corti, Echinococcus multilocularis and E granulosus. Because of its very wide therapeutic index praziquantel is thus particularly suited for eradication programmes, eg, echinococcosis.

Animals↗
PubMed1979

A fluorometric method for the determination of praziquantel in blood-plasma and urine.

Some physicochemical data of praziquantel which may have analytical relevance are reported. For the quantitative determination praziquantel is extracted from plasma or urine by means of organic solvents and then hydrolyzed in an aqueous alkaline solution. The hydrolyzed product is reacted with dansyl-chloride (5-dimethylaminonaphthalene-sulfonylchloride). The dansylated compound is separated and quantified fluorometrically. The limit of determination is 3 micrograms/l in blood plasma and 30 micrograms/d in urine. For both fluids, the imprecision is approximately 7.5%. The method is suitable for the determination of praziquantel in patients or healthy volunteers treated with therapeutic doses.

Chemical Phenomena↗
PubMed1979

Preliminary trials with praziquantel in human infections due to Schistosoma mansoni.

As part of a programme of multicentre trials of the tolerance and therapeutic effect of praziquantel, clinical trials were carried out in Brazil in patients with active Schistosoma mansoni infections, each of whom had a minimum geometric mean egg output of 100 eggs per gram of faeces calculated from multiple pretreatment stool examinations.The first stage was a double-blind assessment of tolerance and efficacy of oral doses of 1 x 20, 2 x 20, or 3 x 20 mg of praziquantel per kg of body weight. Subsequently, single-blind trials explored the effects of 3 x 20 mg/kg at 4-hourly intervals, and a single dose of 50 mg/kg.Side effects increased in frequency as dosage increased. Nausea, epigastric pain, headache, dizziness, and drowsiness were all noted but their severity was mild or moderate and they disappeared in 48 hours. In general, monitoring laboratory tests showed little change.Following a stringent parasitological follow-up, 96% of 28 patients followed at 1 year after treatment with either 3 x 20 mg/kg or 1 x 50 mg/kg were cured. Praziquantel seems to be a very promising drug against S. mansoni and further clinical trials should be strongly encouraged.

Adult↗
PubMed1978

Mutagenicity studies with praziquantel, a new anthelmintic drug, in mammalian systems.

Praziquantel, a new anthelmintic drug with antischistosomal and anticestodal properties, was tested in comparison with a placebo control and a 'positive control' with cyclophosphamide in mammalian test system in vivo for potential mutagenic effects. The test systems used and the tested doses of Praziquantel were: (1) Dominant lethal test on male NMRI mice, 12 mating periods of 4 days each, 1 X 1200 mg/kg BW by mouth; (2) Dominant lethal test on female NMRI mice, treatment during pre-estrus, 1 X 1200 mg/kg BW by mouth; (3) Micronucleus test on male and female NMRI mice, two doses with a 24-h interval and preparation of the femoral marrow 6 h after the second dose, 2 X 300 mg/kg and 2 X 600 mg/kg BW by mouth; (4) Spermatogonial test on the Chinese hamster, two doses with a 24-h interval and preparation of the spermatogonia 48 h after the second dose, 2 X 600 mg/kg BW by mouth. The 1200 mg/kg BW dose corresponded to approximately 1/2 of the LD50 after oral application in the mouse and about 40 times the therapeutic dose (1 X 30 mg/kg BW). The cyclophosphamide doses in the test systems were 1 X 200 mg/kg or 2 X 200 mg/kg BW by mouth. No indication was found of any mutagenic potency of Praziquantel. This agrees with the results of point-mutation tests done by other authors.

Animals↗
PubMed1978

[The efficacy of praziquantel against experimental cysticercosis and hydatidosis (author's transl)].

Praziquantel is active against cysticerci in experimentally infected mice, rabbits, sheep and cattle. After single or repeated application the infectious stages of Hymenolepis nana, Cysticercus fasciolaris, C. pisiformis, C. tennuicollis and C. bovis were killed. The compound is more active against older than against younger stages as demonstrated with H. nana-cystecercoids and C. fasciolaris in mice. Against the tetrahyridia of Mesocestoides corti in mice praziquantel is only effective after an intraperitoneal application of an oily suspension. Praziquantel shows also activity in rodents against the infectious protoscolices of Echinococcus multilocularis but failed to inhibit the growth of the hydatid cysts.

Animals↗
PubMed1977

Experimental chemotherapy of schistosomiasis mansoni. XIII. Activity of praziquantel, an isoquinoline-pyrazino derivative, on mice, hamsters and Cebus monkeys.

In mice experimentally infected with Schistosoma mansoni, praziquantel (2-cyclohexylcarbonyl-1,3,4,6,7,11b-hexahydro-2H-pyrazino[2,1-a]isoquinoline-4-one), administered orally at the levels of 100 and 50 mg/kg, for 5 consecutive days, produces oogram changes in all animals and a pronounced hepatic shift of schistosomes (97.1 and 89.1, respectively). At lowest levels (12.5 and 6.3 mg/kg), alterations in the oogram could still be detected, although hepatic shift of schistosomes was no more evident. After a single intramuscular injection, the results obtained paralleled those observed with a single-dose oral treatment. The hepatic shift was only moderate at 200 and 100 mg/kg and the percentages of worms retained in the liver, after perfusion, were particularly low. When nasal route in a 1-day regimen was used, the results obtained were slightly less evident as compared with those observed by oral route (5-day schedule). Considering the percentage of oogram changes, the degree of hepatic shift of schistosomes and the percentage of worms fixed in the liver, the antischistosomal activity of praziquantel was greater in hamsters than in mice. Actually, a daily dose as low as 12.5 mg/kg, administered for 5 consecutive days, was sufficient to shift 60.4% of the worms towards the liver and to produce alterations of the oogram in 60% of the animals. In Cebus monkeys orally treated with 10 and 20 mg/kg of praziquantel, given 3 times within a single day (total doses of 30 and 60 mg/kg, respectively), a remarkable reduction in worm burden was observed. A single oral or intramuscular dose of 100 mg/kg was found to be curative. One Cebus doses with 100 mg/kg, by nasal spray, was found to harbor only female worms at autopsy performed 69 days after treatment.

Animals↗
PubMed1978

Effect of praziquantel on the free living stages of Schistosoma mansoni.

The effect of the new schistosomicide praziquantel (2-cyclohexyl-carbonyl-1,2,3,6,7,11 b-hexahydro-2H-pyrazino[2,1a]isoquinolin-4-one) on the miracidia and cercariae of Schistosoma mansoni was investigated. In vivo praziquantel inhibits hatching of miracidia for 24 h after administration of 500 mg/kg to infected mice. In vitro a concentration of 10 microgram/ml inhibits subsequent hatching in drug-free water. Free swimming miracidia are rapidly killed by 1 microgram/ml. Even 0.01 microgram/ml is still partially effective. In a solution of 0.03 microgram/ml cercariae lose their ability to swim within 10 min. This effect is reversible in drug-free water. Morphological damage to cercariae incubated in 0.1 microgram/ml is clearly evident. However, cercariae are fully infective when given subcutaneously to mice after a 3-h incubation period. Incubation in 1 microgram/ml reduces the infection rate by 80%. A 2-h incubation in 0.1 microgram/ml almost completely inhibits the percutaneous infection through the abdominal skin. The number of cercariae that develop to schistosomules is reduced by more than 90%. After a 2-h incubation in a concentration of 0.01 microgram/ml the swimming ability of cercariae is impaired in such a way that the number of cercariae penetrating in the tail immersion test and developing to schistosomules is reduced by half. Praziquantel is a more potent protective agent than the molluscicides copper sulphate, sodium pentachlorophenate and Bayluscide or cadmium and zinc ions.

Animals↗
PubMed1979

Schistosoma mansoni: activity responses in vitro to praziquantel.

The effects of praziquantel, a novel antischistosomal compound, on the activity of adult Schistosoma mansoni (Liverpool strain) in vitro were investigated. Worm activity was modified at all concentrations of praziquantel. High concentrations (above 0.5 microgram/ml) produced rapid paralysis, whilst low concentrations of praziquantel stimulated worm activity. It is concluded that such activity modification could lead to worm displacement in vivo.

Animals↗
PubMed1978

Absence of mutagenicity of praziquantel, a new, effective, anti-schistosomal drug, in bacteria, yeasts, insects and mammalian cells.

Praziquantel (Embay 8440, Droncit) a new, effective anti-schistosomal drug, was tested in various short-term assays that have shown a predictive value for the detection of potential carcinogens. Indicator organisms S. typhimurium strains, S. pombe, S. cerevisiae, cultured V79 Chinese hamster cells or human heteroploid cells and Drosophila melanogaster were treated with Praziquantel. The induction of reverse and forward mutations, mitotic gene conversions, X-linked recessive lethals, sister-chromatid exchanges and unscheduled DNA-repair synthesis was scored; rodent-liver microsome-, cell- and host-mediated assays were also performed. Hycanthone, another schistosomicide was included as a positive control. The absence of a genetic activity of Praziquantel uniformly observed in such a battery of tests (i) confirms the assumption that the anti-schistosomal effectiveness of this drug is not related to the mutagenic activity and (ii) should encourage the implementation of extended clinical and field trials.

Animals↗
PubMed1979

Praziquantel: a new schistosomicide against Schistosoma haematobium.

The effectiveness of the new schistosomicide praziquantel was assessed in African schoolchildren infected with Schistosoma haematobium. They were stratified according to the severity of their infection and were then randomly allocated to treatment with two single-dose regimens (30 and 40 mg/kg) and a split regimen of two doses of 20 mg/kg given four hours apart. All three regimens were highly effective and produced few side effects. Children who initially had very high pretreatment egg loads showed a poorer therapeutic response at all dose levels, and further investigations are necessary to find the optimum dose. Because of its effectiveness in a single dose and lack of toxicity, praziquantel may prove to be the ideal schistosomicide.

Adolescent↗
PubMed1979

Preliminary clinical trials with praziquantel in Schistosoma japonicum infections in the Philippines.

Praziquantel, a new antischistosomal compound, was tested for tolerance and efficacy against placebo in two double-blind clinical trials in Philippine patients infected with Schistosoma japonicum.The compound was given orally at a dose of 3 x 20 mg/kg at intervals of 4 hours to a total of 82 patients-some without advanced disease and some with hepatosplenic involvement. A total of 43 patients received placebo. In a single-blind trial, 42 patients were given a single oral dose of 50 mg/kg. Monitoring of vital organ functions included comprehensive laboratory tests and serial electrocardiograms. In 38 patients with hepatosplenic involvement due to advanced stages of infection, serial electroencephalograms were additionally recorded. No toxic effects were observed in any of these examinations.Undesirable side effects occurred in 53% of the patients given 3 x 20 mg/kg and in 70% after a dose of 1 x 50 mg/kg. They consisted mainly of abdominal discomfort, fever, sweating, and occasionally giddiness, but in general were transient and mild. At 6 months post-treatment, 60 of 75 patients treated with 3 x 20 mg/kg and 29 of 41 treated with 1 x 50 mg/kg were completely negative for eggs. At 12 months post-treatment, 25 of 33 and 14 of 26 patients in the two treatment groups were cured. Thus the divided dosage gave a superior therapeutic result. Praziquantel proved to be free of major toxicity, and was well tolerated, highly effective, and easy to administer. Confirmation of results in extended trials may soon permit large-scale treatment.

Clinical Trials as Topic↗
PubMed1978

Clinical pharmacology in normal volunteers of praziquantel, a new drug against schistosomes and cestodes. An example of a complex study covering both tolerance and pharmacokinetics.

The tolerance of Praziquantel (2-cyclohexylcarbonyl-1, 3, 4, 6, 7, 11b-hexahydro-2H-pyrazino-[2, 1-a]isoquinoline-4-one) in oral doses of 1 X 20 mg/kg, 1 X 50 mg/kg, 3 X 10 mg/kg and 3 X 25 mg/kg body weight (tau = 4 h) was tested in a complex study involving 36 healthy volunteers. In addition to the usual assessment of clinical chemistry, haematology, coagulation physiology, urinalysis, clinico-physiological examination including EEG, and medical examination, clinico-psychological parameters were also recorded and special neurological investigations were performed. No clinically relevant changes were found in any of the laboratory parameters, nor in the medical-neurological or clinico-physiological examinations. Based on a few clinico-psychological parameters and subjective comments, the largest daily dose tested (3 X 25 mg/kg = 75 mg/kg) produced a slight, transient disturbance in general well-being, which was barely detectable on objective clinical examination. The pharmacokinetic behaviour was dominated by rapid metabolism and pronounced first-pass metabolism of praziquantel, which greatly limits the value of results obtained by GC analysis of unchanged drug in serum. The peak concentration in serum was reached after 1--2 h, and the elimination half-life for the period 2--8 h was 1--1.5 h.

Adult↗