Specific Treatment for Trypanosoma Cruzi: Lack of Efficacy of Allopurinol in the Human Chronic Phase of Chagas Disease

Abstract

Thirty-five individuals from endemic areas of Central Brazil (age range, 18-64 years; 19 women) in the chronic phase of Chagas disease, with positive serology and presence of circulating parasites detected by one or more recent positive xenodiagnosis, were selected for this study. Allopurinol (900 mg/d) or placebo was administered in a double-blind clinical trial for 60 days. After codes were broken, 23 had been allocated to the intervention group and 12 to the placebo group. Side effects were observed in 11 patients in the intervention group and in 1 in the placebo group. Seventeen patients in the intervention group and 10 in the placebo group completed the trial. Follow-up was performed by monthly xenodiagnosis and serologic tests every 3 months during the first year and at the end of the trial. Xenodiagnosis remained positive in all 17 of the treated group and in all 10 of the placebo group. Serologic tests were persistently positive in both groups after treatment. We concluded that, at the doses used, allopurinol was not effective to clear, in our region, Trypanosoma cruzi from peripheral blood of infected individuals.

2 nd Brazilian Consensus on Chagas Disease, 2015

“…It is also accompanied by satellite lymph node reaction and, sometimes, ulceration. It can be found on any region of the body, especially exposed parts (20) (160) .…”

“…Around the second week of the disease, generalized or localized edema may appear (on the face or lower limbs), regardless of the inoculation site or presence/absence of cardiac failure (160) . Its consistency can be elastic or soft; the elastic is observed only in young children.…”

“…There may be a lesion at the inoculation site (20) (21) (39) (76) (91) (155) (160) . The clinical picture of acute illness in cases of vectorial transmission is polymorphic, ranging from the classical description ̶ a sign of infection at the inoculation site, fever, subcutaneous edema, lymphadenopathy, hepatomegaly, splenomegaly, and evidence of myocarditis and meningoencephalitis ̶ to asymptomatic and oligosymptomatic situations (20) (76) The portal of entry is the ocular conjunctiva (Romaña sign) in 50% of cases and the skin (inoculation chagoma) in 25% of cases; it is unknown in the remaining 25% of cases (160) . However, it is assumed that the ocular route is the most frequently diagnosed as it is easy to recognize, both by the affected individual and the healthcare team.…”

Advanced megaesophagus (Group III) secondary to vector-borne Chagas disease in a 20-month-old infant

“…In this case, the possibility of a congenital form was excluded by the negative results of the maternal serological tests on two occasions, indicating a vector-borne transmission; the initial period of infection was not diagnosed, which is usual in the natural history of Chagas disease 11 .…”

Experiencia terapéutica en un centro para la enfermedad de Chagas

“…Los fármacos clásicos, únicos aprobados hasta ahora para el tratamiento de la enfermedad de Chagas, son un nitrofurano, Nifurtimox (NFX) y un nitroimidazol, Benznidazol (BNZ). Se han incorporado alternativas de efectividad discutida y en estudio,como itraconazol, alopurinol y otras 8,[14][15][16] , en especial en adultos en fase crónica y en casos especiales, como trasplante de órganos. En el país no se encuentra habitualmente disponible BNZ.…”