In 1996, we described a schedule of single-day therapy with praziquantel for management of neurocysticercosis. This treatment resulted in 90% less total dose and costs and 93% less duration of treatment in comparison with the 2-week regimen, achieving similar clinical efficacy.1 It also showed similar results compared with albendazole.2 Recent reports in healthy volunteers have suggested that plasma levels of praziquantel increase with the administration of cimetidine3 and also with a high-carbohydrate diet,4 apparently due to inhibition of cytochrome p450. To investigate the potential clinical advantage of this effect, we compared the praziquantel single-day regimen administered either alone or in combination with cimetidine, and administered simultaneously with a high-carbohydrate diet.
Methods.
We studied 18 patients diagnosed with cysticercosis in brain parenchyma or subarachnoid space at the convexity. Age range was 17 to 64 years (mean 29.2); the study included 10 men and eight women. No patients with parenchymal cysts surrounded by edema and intense enhancing in contrasted studies were selected. No pregnant women were included. A diagnosis of cysticercosis was confirmed by ELISA in CSF and imaging studies (CT or MRI or both). All had seizures as the principal symptom. The mean time between the beginning of symptoms and treatment was 8 weeks. Informed consent was obtained from each patient. Subjects were randomly separated into three groups of six patients each. Group 1 received three oral doses of 25 mg/kg of praziquantel at 2-hour intervals (at 7, 9, and 11 am) after an overnight fast. Group 2 received the same three oral doses plus 400 mg of cimetidine administered 1 hour before each praziquantel dose. Group 3 received a high-carbohydrate diet (650 calories) 30 minutes before the first dose of praziquantel. All patients received dexamethasone (8 mg intramuscular) 6 hours after the last dose of praziquantel followed by the same dosage for the next 2 days. All patients remained in the hospital during treatment. Clinical evaluations were made 1, 2, 4, 8, 12, and 24 weeks after treatment, all by the same neurologist (M.L.). Follow-up CT scanning was performed 4, 12, and 24 weeks after treatment, and MRI was performed 24 weeks after treatment. Efficacy of treatment was evaluated by the individual disappearance of cysts and by the percentage of disappearance of lesions in every patient. Imaging studies were independently reviewed by a neurologist (T.C.) and a neuroradiologist blinded to treatment group source; interobserver results were identical. Blood samples were taken immediately before the last dose of praziquantel and were assayed by high-performance liquid chromatography.5 The Mann–Whitney test was used to assess differences in the median percentage of cysts and to assess plasma levels. The SPSS-9 analytical program was used.
Results.
Sixteen patients were asymptomatic and two had hemiparesis due to localization of cysts that recovered completely after treatment. Two patients had mild headache as a side effect, which disappeared in next 24 hours. Of 35 lesions, 29 (83%) disappeared within 3 months. In Group 1, the mean plasma level of praziquantel was 217 ng/mL, in Group 2, 699 ng/mL, and in Group 3, 1125 ng/mL. Statistical differences were found between Groups 1 and 3 (p = 0.004). The disappearance rate of the number of cysts was substantially different between Groups 1 and 3 (p = 0.038). During follow-up, one patient from Group 2 presented with seizures at week 14, which were probably due to discontinuation of antiepileptic therapy.
Discussion.
The treatment induced 83% elimination of cysticerci. This value is similar to that reported for a 1-week regimen with albendazole.3 All patients were asymptomatic in the follow-up period. Although no correlation has been found between plasma levels and therapeutic response, our results show that a high-carbohydrate diet or coadministration with cimetidine increases plasma levels of praziquantel and clinical efficacy without serious side effects. Our data show that the increment was greater after a high-carbohydrate diet and the therapeutic response was better with this treatment (table). This single-day therapy optimized with a high-carbohydrate diet presents the advantages of lower costs, shorter treatment period, no toxicity, and the drug intake can be easily supervised at the outpatient clinic without hospitalization. This treatment seems to give results similar to those reported with the 7-day regimen of albendazole, and even better results than those with the 15-day regimen of praziquantel, assuring good compliance with the therapy. Whether these advantages could be increased by simultaneous administration of cimetidine merits further study.
Plasma levels and response to therapy
Acknowledgments
Acknowledgment
The authors thank Dr. Jesus Higuera Calleja for his participation as the neuroradiologist evaluator.
- Received June 4, 2001.
- Accepted July 19, 2001.
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- Optimization of the single-day praziquantel therapy for neurocysticercosis
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