Clinical meaning
Understanding pharmacotherapeutic principles is foundational to safe and effective NP prescribing. The properties of an ideal drug include: effectiveness (producing the intended therapeutic response), safety (wide therapeutic index between therapeutic and toxic doses), selectivity (acting on target tissues with minimal off-target effects), reversible action (effects dissipate when drug is discontinued), predictability (consistent dose-response relationship across patients), ease of administration (patient-friendly route and dosing schedule), freedom from drug interactions (minimal CYP enzyme induction/inhibition), chemical stability (maintains potency during storage), and low cost (accessible to patients).
Drug nomenclature follows three naming systems: the chemical name (describes molecular structure, used in research), the generic name (non-proprietary/official name assigned by regulatory bodies - USAN in US, INN internationally), and the trade/brand name (proprietary name assigned by manufacturer for marketing). NPs should prescribe by generic name when possible to reduce cost and confusion.
Pharmacokinetic optimization involves understanding absorption (bioavailability, first-pass effect, food interactions), distribution (protein binding, volume of distribution, blood-brain barrier penetration), metabolism (Phase I oxidation via CYP450 enzymes, Phase II conjugation reactions, pharmacogenomics), and elimination (renal vs hepatic clearance, half-life, steady-state achievement at 4-5 half-lives).
Therapeutic drug monitoring (TDM) is essential for drugs with narrow therapeutic indices: digoxin (0.5-2.0 ng/mL), lithium (0.6-1.2 mmol/L), phenytoin (10-20 mcg/mL), vancomycin (trough 10-20 mcg/mL), aminoglycosides (peak and trough), theophylline (10-20 mcg/mL), and immunosuppressants (tacrolimus, cyclosporine, sirolimus). Drug levels should be drawn at steady state (4-5 half-lives after dose initiation or change) and at appropriate timing relative to dosing (trough levels drawn immediately before next dose).