Navigating heart failure medications in obstetric practice

Figure 2 Effect of physiological changes during pregnancy on the pharmacokinetics of heart failure drugs. It summarizes key physiological changes during pregnancy and their impact on drug pharmacokinetics across absorption, distribution, metabolism, and excretion. Major alterations include reduced gastrointestinal motility, increased plasma volume and body fat, modified hepatic enzyme activity (e.g., induction of CYP3A4, inhibition of CYP1A2), and elevated glomerular filtration rate. These changes significantly affect drug levels: Absorption rates decrease, volume of distribution increases for hydrophilic drugs, unbound drug concentration rises, and clearance is enhanced for many agents (e.g., digoxin, atenolol). Understanding these adaptations is crucial for dosing adjustments and therapeutic drug monitoring in pregnant patients. CL: Clearance; DME: Drug metabolising enzyme; GFR: Glomerular filtration rate; Vd: Volume of distribution.