Nifurtimox (Lampit) is a nitrofuran derivative whose
likely mechanism of action for killing of trypanosomes is through the
production of activated forms of oxygen. Nifurtimox is reduced to the nitro
anion radical, which reacts with oxygen to produce superoxide and hydrogen peroxide.
The free radical metabolites, an absence of parasite catalase, and a peroxide
deficiency lead to lipid peroxidation and cell damage. This production of
acti-vated oxygen results in toxicity to the protozoal cells.
The drug is given orally and
is well absorbed from the gastrointestinal tract. It is rapidly metabolized,
and only low levels are found in blood and tissues. The drug is excreted in the
urine, primarily in the form of metabolites.
Nifurtimox is trypanocidal
and exerts an effect on the trypomastigote and amastigote forms of T. cruzi. It is effective in the
treatment of the acute form of Chagas’ disease but is less effective once the
disease be-comes chronic. The drug is moderately well tolerated, and treatment
generally lasts 3 to 4 months. Cure rates of 80 to 90% have been reported.
Since much of the tis-sue damage caused by the disease is irreversible, early
diagnosis and treatment are important. Nifurtimox has also been used in T. gambiense infection with
Although side effects occur
in approximately half the patients treated with nifurtimox, it is necessary to discontinue
treatment in only a minority. Nausea, vom-iting, abdominal pain, skin rashes,
headache, insomnia, convulsions, and myalgia all have been reported.