Management decisions regarding poisoning or envenoming in the pregnant or lactating patient take into consideration the risks to the fetus or infant of the poisoning or its treatment. Pregnancy-induced physiological changes impact on drug pharmacokinetics and pharmacodynamics in the following ways:
- Absorption: Delayed gastric emptying and intestinal transit time slow drug absorption and may prolong the period where decontamination is of potential benefit
- Distribution: Increased blood volume (45 – 50%) increases volume of distribution and potentially decreases plasma levels; dilution of plasma proteins increases free drug levels
- Elimination: Hepatic enzyme systems are altered by circulating hormones; renal blood flow and glomerular filtration rate increase.
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