Poisoning during Pregnancy and Lactation

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.


  • Anderson GD. Pregnancy-induced changes in pharmacokinetics. A mechanistic-based approach. Clinical Pharmacokinetics 2005; 44(10):989-1008.
  • McElhatton PR, Sullivan FM, Volans GN. Paracetamol overdose in pregnancy: analysis of the outcomes of 200 cases referred to the teratology information service.  Reproductive Toxicology 1997; 10:85-94.
  • Syme MR, Paxton JW, Keelan JA. Drug transfer and metabolism by the human placenta. Clinical Pharmacokinetics 2004; 43(8):487-514.
  • Wiles JM, Clark LE, Herrera JL. Acetaminophen overdose in pregnancy.  Southern Medical Journal 2005; 98(11):1118-1122.

Toxicology Handbook

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