Untoward Effects of Anti-amebic Drugs

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  • Pacific Institute of Tropical Medicine within the Hooper Foundation for Medical Research, University of California, San Fransisco
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The untoward effects of the four types of chemical agents which are used extensively in treating amebiasis today are presented. Emetine hydrochloride is toxic for most mammals, including man, in 10 to 25 mgm. per kilogram total doses. The heart muscle bears the burden of the toxic effect, as illustrated in the case cited and in animal pathologic studies. Ten milligrams per kilogram body weight is the maximum safe total dose of emetine hydrochloride in patients with an amebic hepatitis and free from heart damage. No untoward effects have been observed with the use of the kurchi alkaloids.

Acetarsone ("stovarsol") may exhibit toxic manifestations in one of every 6 cases treated. A atient showing intolerance to 5.0 grams of this agent taken over a twenty-eight day period is recorded. Acetarsone, in our opinion, is too toxic for routine clinical use. Animal experiments emphasize this point.

Carbarsone has been given to 330 patients in total doses (orally and rectally) ranging from 75 to 2100 mgm. per kilogram in divided amounts over a period of fifteen months. A single instance of intolerance is reported in a patient with acute hepatitis who had an untoward reaction to 5.0 grams of the drug given in ten days. This experience further emphasizes our previous warning that an arsenical should not be given in the presence of hepatitis. Slight gastric distress has also been noted but no evidence of damage to the kidneys, optic nerve, skin, or other tissues has been observed by us to date.

Liver damage has been reported elsewhere, from 'the use of chiniofon ("yatren") but we have abandoned this agent becauseof its relative inactivity as an amebacide. Vioform, a related halogenated oxyquinoline, is more effective and has been used in preference to chiniofon. Three of 60 patients given the drug orally in doses ranging from 100 to 1000 mgm. per kilogram over a period of twelve months, have experienced gastric and other distress but no other definite untoward effects. The drug cannot be used rectally because of local irritation. Since the soluble hydrochloride of vioform causes local effects on mucous membranes, it is possible that a gastric hyperacidity may be responsible for the distress experienced by these three patients. Enteric coated capsules may eliminate this difficulty.

Bismuth subnitrate may cause methemoglobinemia and on this account the use of bismuth subcarbonate is stressed to avoid "nitrite" effect. Heptylresorcinol ("di-hydranol") irritates the mucous membrane of the gastroenteric tract and is not to be recommended as an amebacide until more adequate data on its efficiency are available.

Author Notes

With the technical assistance of (Mrs.) Jeanette Van Dalsem Anderson.