NAPLEX key terms

A drug whose effective and toxic dose ranges are close together, so small changes in dose or blood level can cause treatment failure or serious harm. Examples include warfarin, digoxin, lithium, and phenytoin.

Measuring drug concentrations in blood at defined times to individualize dosing. It is used for drugs with a narrow therapeutic index, unpredictable pharmacokinetics, or high toxicity risk, such as vancomycin and aminoglycosides.

The point during regular dosing when the amount of drug entering the body equals the amount eliminated, so plasma concentrations plateau. It is usually reached after about four to five half-lives.

A larger initial dose given to reach therapeutic concentrations quickly, before maintenance dosing achieves steady state. It is calculated from volume of distribution and the target concentration.

Metabolism of an oral drug by the intestinal wall and liver before it reaches systemic circulation, which lowers bioavailability. Drugs with a large first-pass effect often need higher oral doses or a different route.

The time needed for plasma drug concentration to fall by half. It guides dosing interval, time to steady state, and how long effects or toxicity may persist after a drug is stopped.

Any noxious, unintended response to a drug that occurs at normal doses. Reactions range from predictable dose-related effects to unpredictable hypersensitivity or idiosyncratic responses.

The strongest safety warning the FDA requires on a prescription drug label, highlighting serious or life-threatening risks. It may require restricted use, patient monitoring, or dispensing a medication guide.

A structured process of obtaining and comparing a patient's full medication list at care transitions, then resolving discrepancies. It reduces omissions, duplications, and dosing errors.

The extent to which a patient takes medications and follows a treatment plan as agreed with the prescriber. Cost, side effects, regimen complexity, and health beliefs strongly influence it.

The study of what the body does to a drug: absorption, distribution, metabolism, and excretion. It explains how dose, route, and patient factors determine drug concentrations over time.

A theoretical volume relating the total amount of drug in the body to its plasma concentration. Large values suggest extensive tissue distribution; small values suggest confinement to blood.

The volume of plasma cleared of drug per unit time by metabolism and excretion. It determines the maintenance dose needed to sustain a target steady-state concentration.

The study of what a drug does to the body, including receptor binding, mechanism of action, potency, efficacy, and the resulting therapeutic or toxic effects.

The absence of a significant difference in the rate and extent of absorption between two products containing the same active ingredient, usually a generic product and its brand reference.

An FDA-approved product containing the same active ingredient, strength, dosage form, and route as a brand drug, shown to be bioequivalent and marketed after patent protection ends.

A calculation method for combining two preparations of different strengths to produce a specified intermediate strength. It is commonly used when adjusting alcohol, dextrose, or ointment concentrations.

A concentration expressed as a ratio of drug to volume or weight, such as 1:1000 meaning 1 g in 1000 mL. It is common for topical, ophthalmic, and irrigation solutions.

A concentration expressed as parts per hundred, such as 5% w/v meaning 5 g of drug per 100 mL. It is the basis for many compounding and intravenous calculations.

An estimate of glomerular filtration calculated from serum creatinine, age, sex, and weight, often with the Cockcroft-Gault equation. It is used to adjust doses of renally eliminated drugs.

The property of a solution having the same osmotic pressure as body fluids, which prevents cells from swelling or shrinking. It is important for parenteral, ophthalmic, and nasal preparations.

Preparing sterile medications such as intravenous admixtures and ophthalmics using aseptic technique in an appropriately classified cleanroom, following USP standards to prevent microbial and particulate contamination.

The maximum time a compounded or opened sterile preparation may be stored and used, based on stability, storage conditions, and contamination risk. It may be shorter than the manufacturer expiration date.

A continually updated list of medications approved for use and coverage within a health system or insurance plan, chosen for safety, efficacy, and cost.

A multidisciplinary group of physicians, pharmacists, and other clinicians that evaluates drugs and sets formulary policy, therapeutic guidelines, and medication-use standards.

A payer requirement that the prescriber obtain approval before a specific medication is covered, usually to confirm medical necessity or that formulary criteria are met.

The official order form a DEA-registered purchaser uses to obtain Schedule I or II controlled substances from a supplier. It must be completed accurately and retained as a record.

A running, real-time record of every controlled substance received, dispensed, and destroyed, reconciled against physical counts to detect theft or diversion.

Removal or correction of a marketed drug because of a defect or safety risk. The FDA classifies recalls as Class I, II, or III based on the likelihood and severity of harm.

A collaborative counseling style that helps patients identify their own reasons for change and resolve ambivalence about treatment, rather than telling them what to do.

A counseling technique in which the patient explains in their own words how they will take a medication, letting the pharmacist confirm understanding and correct misunderstandings.

A patient's ability to obtain, understand, and use health information to make decisions. Low health literacy calls for plain language, pictures, and confirmation of understanding.

An FDA-approved leaflet dispensed with certain medications that have serious or life-threatening risks, written for patients. Pharmacists must provide it when it is required.

Fully focusing on a patient, reflecting back content and feelings, and asking clarifying questions to confirm understanding and build trust during counseling.

A DEA category for drugs with high abuse potential and accepted medical use, such as oxycodone and amphetamine. Prescriptions cannot be refilled and require strict recordkeeping.

A federal law that protects the privacy and security of patients' health information and sets rules for when and how pharmacies may use or disclose it.

Individually identifiable health information created or received by a covered entity, such as a prescription or diagnosis linked to a patient. It is protected under HIPAA.

A state-run electronic database that collects dispensing data for controlled substances, helping prescribers and pharmacists identify overlapping prescriptions, misuse, and diversion.

Any preventable event that may cause or lead to inappropriate medication use or patient harm, including mistakes in prescribing, dispensing, administration, and monitoring.

A federal law requiring an interoperable electronic system to track prescription drugs through the supply chain, helping prevent counterfeit, stolen, or contaminated products from reaching patients.