Determining the Optimal Dosing of Methyldopa in Pregnancy-Induced Hypertension Using PBPK-PD Modeling

Area of Science:

• Pharmacology
• Maternal-Fetal Medicine
• Computational Biology

Background:

• Pregnancy-induced hypertension poses risks to mothers and fetuses.
• Methyldopa is a common, safe antihypertensive, but pregnancy alters its pharmacokinetics (PK) and pharmacodynamics (PD).
• Optimizing methyldopa dosing in pregnancy is challenging due to physiological changes.

Purpose of the Study:

• To develop and validate a pregnancy-specific physiologically based pharmacokinetic-pharmacodynamic (PBPK-PD) model for methyldopa.
• To optimize methyldopa dosing strategies for managing pregnancy-induced hypertension.
• To support individualized treatment plans for improved maternal and fetal outcomes.

Main Methods:

• Developed a PBPK-PD model for methyldopa using PK-Sim, MoBi, and MATLAB.
• Incorporated pregnancy-specific physiological parameters.
• Validated the model for non-pregnant and pregnant states, integrating PK/PD for mean arterial pressure (MAP) simulation.

Main Results:

• The PBPK-PD model showed good fit and appropriate parameters.
• Phenol sulfotransferase (PST) activity remained stable during pregnancy.
• Simulations indicated 500 mg as the optimal methyldopa dose for MAP ≤ 130 mmHg; combination therapy is advised for MAP > 130 mmHg and during the initial 48 hours due to delayed onset.

Conclusions:

• The developed PBPK-PD model is a valuable tool for optimizing methyldopa therapy in pregnancy.
• Personalized treatment strategies can be supported, improving blood pressure management.
• Enhanced maternal and fetal health outcomes are anticipated through optimized methyldopa use.