Exhalation, drug excretion

In species where reabsorption of drugs from the gastrointestinal tract increases the half-life of elimination, salivary secretion represents another important excretion route. The large volume of alkaline saliva produced by ruminants offers the possibility of trapping the acidic drugs. Exhalation of products of drug metabolism, such as carbon dioxide and water, can also account for drug excretion. 

Although not widely reported in the scientific literature, other organs in the body are capable of drug excretion. The primary route of elimination of some inhalation anesthetics (e.g., isoflurane) is exhalation. 

Similar considerations must also apply to the time at which samples are taken for the determination of pollutants, in therapy control, and in the detection of abuse of drugs and medicaments. For example, many hydrocarbons can be determined in blood only if samples are taken during or shortly after exposure, as exhalation, metabolism, excretion, and deposition in body tissues can quickly cause the blood concentration to fall below the limit of detection. 

Excretion The physiological process in which the chemical or metabolite is eliminated from the body through urine, feces, sweat, or exhaled gas Eye corrosion The production of irreversible tissue damage in the eye following the anterior surface contact of a substance or chemical Eye irritation Production of an irreversible change in the eye Fetotoxic Adverse health effects to the fetus FFDCA Federal Food, Drug, and Cosmetic Act... 

The final step is excretion of the drug and metabolites from the body. Water-soluble materials are excreted in the urine and in sweat. If a metabolite is a gas, such as CO2, or has appreciable vapor pressure, as does ethanol, the metabolite can be eliminated by exhalation. Excretion in feces, tears, and any other body fluid is also possible. 

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