PHAR 4634 - Chapter 16 Page 4 Previous Chapter | Previous Page | Index | Next Page | Next Chapter

Pulmonary excretion

The lung is the major organ of excretion for gaseous and volatile substances. The breathalyzer test is based on a quantitative pulmonary excretion of ethanol. Most of the gaseous anesthetics are extensively eliminated in expired air.

How a Breathalyzer works

Salivary excretion

This is not really a method of drug excretion as the drug will usually be swallowed and reabsorbed, thus a form of 'salivary recycling'. Drug excretion into saliva appears to be dependent on pH partition and protein binding. This mechanism appears attractive in terms of drug monitoring, that is determining drug concentration to assist in drug dosage adjustment. For some drugs, the saliva/free plasma ratio is fairly constant. Therefore drug concentrations in saliva could be a good indication of drug concentration in plasma. For some drugs localized side effects maybe due to salivary excretion of the drug.

This page was last modified: 18 June 2002

Copyright 2001 David W.A. Bourne

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