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TRANSA~IONS OF THE ROYAL SOCIETY OF TROPICAL MED~NE AND HYC~-JE (1990) 84, CORRESPONDENCE

1 Correspondence 1

Neurocysticercosis: treatment with albenda- zole

I read with considerable interest the paper by Agapajev et al. (1989: Transactions, 83, 377-383). While the results were undeniably good, I am very concerned about the doses of albendazole used, without comment, by the authors. The dosages recommended for the treatment of hydatid disease (800 mg/d for 28 d-approximately 12-15 mg/kg/d in adults) are the maximum acceptable based on the toxicological information available (Horton, 1989: Transactions, 83, 97-102). There are no data to support the use of doses of 20-30 mg/kg, whether for short or prolonged periods, as suggested in the paper. Benzimidazoles are potentially toxic, particularly to the liver, but this risk was not evaluated.

The difference between groups II and III in respect of dose is not clear, but both groups appear to have received doses above the recommended maximum. Little benefit seems to have resulted from the higher dose regimen used in group III. Furthermore, the regimen in group I was not properly evaluated in comparison with the other groups, the numbers being substantially lower and the duration of follow-up shorter.

The findings of this paner are at variance with those of other authors, notably Escobedo et al. (1987: Archives of Internal Medicine. 147. 738-741) and Sotelo et al. (1988: Archives of Neurology, 45,’ 532- 534), who successfully used doses of 15 mg/kg for one month. Indeed, it was their impression that shorter courses were possibly as effective as longer ones (Escobedo et al. 1988: Investigation Medica Znterna- cional, 15, supplement 1, 23-26). The difference between the studies may lie in the severity of disease, although there is no obvious evidence to suggest this. Further research is therefore needed to establish an effective and wise dose of albendazole for the treat- ment of neurocvsticercosis.

Smith Kline and French Laboratories Ltd John Horton

21 June 1989 Weluyn Garden City Hertfordshire, AL7 IEY, UK

Neurocysticercosis: treatment with albenda- zole-a reply

Despite the relevance of Dr Horton’s comments in the letter above, it should be pointed out that our paper referred to the treatment of neurocysticercosis (NC) and not of hydatid cysts, as mentioned by him. Secondly, the schedule used by us consisted of a combination of albendazole (ABZ) and dextrochlor- opheniramine (DCP) for the reasons explained in the text, which deserved to be emphasized since the exceptionally high tolerance to higher ABZ doses (up to 30 mg/kg/d) must have been linked to the anti- inflammatory effect of the antihistamine drug. It should be pointed out that the histamine released during the antiparasitic therapeutic process, in addi- tion to being responsible for the inflammatory pro-

cess, also has an immunodepressant action. The histological studies cited bv Dr Horton were

conducted on hboratory animals, &th no reference to the occurrence of similar effects at the ABZ doses used by us for clinical purposes. Neither of the 2 patients with cysticercosis who died in our study showed signs of toxicity to the liver or to any other organ.

Furthermore, the clinical evaluation and laboratory tests (hepatic, renal and haematological function) to which our patients were submitted and the long follow-up time permitted us to consider this associa- tion to be effective and free from important toxic or side effects in the treatment of NC.

It should be remembered that 2-3 weeks elapse between evagination of the scolex and death of the cysticercus and that the action of ABZ occurs through a decrease in glucose uptake and gluconeogenesis in the parasite, leading to death by starvation. As for the doses recommended by Escobedo et al. (1987: Arc- hives of Internal Medicine, 147, 738-741) and Sotelo et al. (1988: Archives of Neurology, 45, 532-534 and 1130-1133), different criteria for patient selection and classification were used. In our study, the severity of the clinical form of NC was characterized bv clinical neurological, cerebrospinal fluid (CSF) and tomo- graphic observations, whereas the above authors basically used tomographic criteria.

As mentioned in our text, ethics prevented us from increasing the number of patients in group I in view of the fact that the action of the drug was demonstrated in half the patients when the 15 mg/kg/d dose was reached. In our patients, we observed discrete to intense exacerbation of the clinical picture between the 2nd and 6th days (80% of cases). On the other hand, in 70% of all patients there was clinical and laboratory (CSF) exacerbation at each increase in dose.

Apparently there is no difference between groups II and III if we do not consider the total dose and esneciallv the time of treatment. as clearlv shown in Table l<of the paper. ’ d

Finally, we would like to point out that our studies and conclusions were directed at neurologists who do not have tomographic support but who need a safe schedule for the treatment of their NC patients.

Svetlana Agapejev Department of Neurology and Psychiatry 1 August 1989 Faculty of Medicine-UNESP 18610 Botucatu, SP Brazil

Sciapodes in tropical medicine Price (1989: Transactions, 83, 574) confidently

identified the portrayal of the Sciapod in the Mappa Mundi of Hereford Cathedral with the elephantiasis found in Ethiopia today. The Sciapodes (Zxtaq96~g)

were well known to the classical writers, and to the medieval authors and illustrators who copied them. They were certainly known to the Greeks and Romans. One of the main sources of medieval information was the encyclopedic natural history of Pliny the elder (1st century AD), who copied much from the Greek compiler Ctesias of Cnidus (5th to 4th