A 26-year-old woman who has never been pregnant is seeking preconception care as she is planning to pursue pregnancy in a couple of months. Currently, she has no symptoms to report and on review of body systems, there were no concerns. Her past medical history is significant for a history of rheumatic fever as a child.

Question 3

The woman’s signs of confusion are due to diphenhydramine in the cold medication. This element has a sedative effect and is known to cause drowsiness and confusion, especially in older adults (McKeirnan et al., 2020). Hence, although she uses the correct dosage, her advanced age increases the risk of side effects.

Question 4

Warfarin metabolism occurs primarily in the liver through the action of the cytochrome P450 enzyme system. It is a racemic mixture of R and S enantiomers, with the S-enantiomer being more potent and metabolized by CYP2C9 (Cheng et al., 2022). Warfarin does cross the placental barrier. Therefore, its use during pregnancy increases the risk of fetal exposure, potentially leading to birth defects, especially if used during the first trimester (Cheng et al., 2022). Given the woman’s desire to conceive, it is crucial to consider alternative anticoagulation therapies.

Question 5

Hepatic drug metabolism in children aged one year and older is similar to that of adults compared to infants. Infants lack fully developed hepatic drug-metabolizing enzymes, making drug metabolism less efficient (Van Groen et al., 2021). As children grow and develop, the activity of drug-metabolizing enzymes in the liver, particularly the cytochrome P450 system, mature and approach adult levels (Van Groen et al., 2021).

This maturation leads to a more efficient and effective metabolism of drugs in children aged one or older. However, the specific maturation rate can vary for different enzymes and drugs. Therefore, dosing adjustments and considerations based on age and weight are still necessary to ensure safe and effective drug therapy in pediatric patients.

Question 6

Protein binding in the neonate refers to how drugs and other substances in their bloodstream attach to proteins, primarily albumin, affecting their distribution and effectiveness. Neonates have lower albumin levels, making them more susceptible to drug interactions and potential toxicity (Leroux et al., 2019). This reduced protein binding capacity can lead to higher concentrations of free, unbound drugs in their system, increasing the need for careful dosing and monitoring in newborns.

References

Cheng, S., Flora, D. R., Rettie, A. E., Brundage, R. C., & Tracy, T. S. (2022). Pharmacokinetic modeling of warfarin І–model-based analysis of warfarin enantiomers with a target mediated drug disposition model reveals CYP2C9 genotype-depe