Ingested substances

Symptoms may be caused by an underlying disease or co-morbidity, or by a drug, rather than by an ingested substance. 

A Drug Information Centre may also serve as a Poison Control Centre, which will include services towards the public. The Poison Control Centre answers questions concerning possibly toxic effects of any kind of ingested substance, animal bites or stings, or other forms of chemical exposure. This kind of service will require a 24-hour attendance, whereas the work of answering drug related questions usually can be limited to office hours. 

Percentages are based on total number of known ingested substances rather than the total number of human exposure cases. 

En route from the intestinal lumen to the general circulation, the ingested substance is broken down enzymatically, e.g., by cytochrome P450 oxidases. 

Most dissolution of ingested substances occurs in the stomach, and most absorption occurs in the intestinal tract (Sipes and Badger, 2001). However, materials that are dissolved in the stomach may not all be absorbed across the intestinal tract lining. For simple diffusion across the intestinal wall into the bloodstream, a toxin must be in the most lipid-soluble (nonionized) form, which is based on its acid/base characteristics (Rozman and Klaasen, 2001). For example, a weak acid is mainly in the nonionized (lipid soluble) form in the stomach and in the ionized... 

Exogenous clearance eliminates ingested substances within a certain period of time and in a certain quantity (e. g. foreign substances used in diagnostics). 

Ingest substances Reluctant to seek Comorbid Increased volume of distribution Salicylates... 

Conversion of ingested substances to less active forms by gastrointestinal enzymes or the acidic environment of the stomach... 

Conversion of ingested substances to less active forms by GI enz)unes or the acidic environment of the stomach is a factor for some environmental contaminants. Hexavalent chromium provides a good example, because it can be rapidly reduced to the relatively nontoxic bivalent form in the stomach. The recently completed positive cancer bioassay on hexavalent chromium conducted by the U.S. National Toxicology Program (NTP) appears to indicate, however, that this conversion is not complete at the concentrations administered (NTP 2007). 

Death. Accidental poisonings and deaths in humans that were attributed to the ingestion of nitrobenzene have been reported but as discussed in Section 2.2.2.1, these studies usually lack clear chemical identification of nitrobenzene as the ingested substance. In those inhalation case studies (Stevens 1928 Stevenson and Forbes 1942) and oral case studies (Carter 1936 Leader 1932 Myslak et al. 1971) in which the patients were apparently near death due to severe methemoglobinemia, termination of exposure and prompt medical intervention resulted in gradual... 

There is the quahfieation that enthusiasm for a particular substance or substances should be tempered by the faet that the proeesses of digestion and assimilation may affect the biochenueal nature of ingested substances. Of course, if it works, it works. 

OTHER COMMENTS used as an herbicide poisonous by ingestion substance is metabolized in the body into 2,4-D (Dichlorophenoxyacetic acid) physical and toxicological properties may change due to carrier solvents used in commercial formulations. 

These studies are required to measure the concentration/lime profiles of the ingested substance and its metabolites in the various organs and tissues of the body. Human biochemical studies that fall into these categorie.s are also included in this section, whereas other human studies are included under observations in humans. 

Farer LS (1976) Isoniazid and liver injury. Ann Intern Med 84 753 Feinmann L (1975) Lung parenchymal changes due to ingested substances. Drug-induced lung disease pulmonary eosinophilia and sulphonamides. Proc R Soc Med 68 440 Fellner MJ (1970) Nebenwirkungen durch Isonicotinsaurehydrazid. Hautarzt 21 320 Flach A (1981) Photosensitivity to sulfisoxazole ointment. Arch Ophthalmol 99 609 Fleck R (1981) Nitrofurantoin toxicity. Pa Med 84 36... 

The central aspect of clinical testing in infants should include the evaluation of a diverse spectrum of immune functions in response to an added substance. To develop the appropriate tests for assessing the safety of the immunological responses to new substances, it is useful to first identify the target tissues affected by the interaction of ingested substances with the host immune system (Table 6-7). 

Ipecac has emetic properties, acting both centrally (possibly through the involvement of a 5-HT4 receptor) and loeally to cause vomiting. Emetic action starts to fade after 30 min from administration. In small doses it has diaphoretic, expectorant, andstimulantproperties (usd 26th). Ipecac also reduces absorption of ingested substances in a time-dependent fashion. This effect becomes insignificant after ca. 90 min from administration of ipecac syrup. ... 

For other toxic materials, water or milk should be given as above, and if it is certain that the ingested substance was not a corrosive or a hydrocarbon such as a petroleum distillate, vomiting may be induced with syrup of ipecac. This latter procedure should only be approached with great care, especially if one is unfamiliar with first aid procedures. Immediate medical care is also required. For all poison ingestion, workers should be prepared to provide medical personnel with details about the substance ingested, its quantity and concentration, and treatment given. 

---