Prescribing Principles

Evidence-based prescribing requires NPs to integrate pharmacokinetic principles including absorption, distribution, metabolism, and excretion (ADME) with patient-specific factors such as age, organ function, and comorbidities. Renal dosing adjustments rely on creatinine clearance calculated via the Cockcroft-Gault equation: CrCl = [(140 - age) x weight in kg] / (72 x serum creatinine), multiplied by 0.85 for females, or estimated glomerular filtration rate (eGFR) derived from the CKD-EPI equation. Hepatic dosing considers the Child-Pugh classification (scores A through C based on bilirubin, albumin, INR, ascites, and encephalopathy) and cytochrome P450 enzyme activity, which can be altered by genetic polymorphisms, disease states, and concomitant medications. Pregnancy safety assessment has shifted from the former FDA letter categories (A, B, C, D, X) to the Pregnancy and Lactation Labeling Rule (PLLR), requiring clinicians to evaluate individual risk-benefit data rather than relying on simplified categories.