Gastrointestinal tract toxin elimination

These studies represent the first report of the metabolism of brevetoxins by mammalian systems. PbTx-3 was rapidly cleared from the bloodstream and distributed to the liver, muscle, and gastrointestinal tract. Studies with isolated perfused livers and isolated hepatocytes conflrmed the liver as a site of metabolism and biliary excretion as an important route of toxin elimination. [ H]PbTx-3 was metabolized to several compounds exhibiting increased polarity, one of which appeared to be an epoxide derivative. Whether this compound corresponds to PbTx-6 (the 27,28 epoxide of PbTx-2), to the corresponding epoxide of PbTx-3, or to another structure is unknown. The structures of these metabolites are currently under investigation. 

D. Enhancement of Elimination Enhancement of elimination is possible for a number of toxins, including manipulation of urine pH to accelerate renal excretion of weak acids and bases. For example, alkaline diuresis is effective in toxicity due to fluoride, isoniazid, fluoroquinolones, phenobarbital, and salicylates. Urinary acidiflcation may be useful in toxicity due to weak bases, including amphetamines, nicotine, and phencyclidine, but care must be taken to avoid acidosis and renal failure in rhabdomyolysis. Hemodialysis or hemoperfusion enhances the elimination of many toxic compounds, including acetaminophen, ethylene glycol, formaldehyde, lithium, methanol, procainamide, quinidine, salicylates, and theophylline. Cathartics such as sorbitol (70%) may decrease absorption and hasten removal of toxins from the gastrointestinal tract. 

D. Cathartics. Controversy remains over the use of cathartics to hasten elimination of toxins from the gastrointestinal tract. Some toxicologists still use cathartics routinely when giving activated charcoal, even though little data exist to support their efficacy. 

Swainsonine is water soluble and is rapidly absorbed from the gastrointestinal (GI) tract. It circulates through the body system, and is excreted in the urine, milk and fece after 5-6 days pratically no toxin remains in the serxun. Swainsonine is eliminated partially in milk and it can be fed to nursing calves and lambs, developing lesion, such as cats that feed milk from cows that consumed locoweed. Reversal of the effects of intoxications are slower, thus week or months may be required for recovery of cell function. Some CNS neurons are lost and cannot replaced [158]. 

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