TT Pharmacy Registration Exam flashcards

36 cards. Read the term and the definition here. The deck at the top of this page is optional.

Bioavailability formula

Absolute bioavailability F = (AUC oral / AUC IV) × (Dose IV / Dose oral). It quantifies the fraction of an administered dose reaching systemic circulation unchanged.

Half-life equation

For first-order elimination, t½ = 0.693 / k. Approximately five half-lives are needed to reach about 97% of steady-state plasma concentration.

Higuchi release model

Describes drug release from a matrix as proportional to the square root of time (amount ∝ √t). It applies to diffusion-controlled sustained-release systems.

Biopharmaceutics Classification System

Classifies drugs by aqueous solubility and intestinal permeability into four classes (I–IV). Class I is high/high; Class IV is low solubility and low permeability.

Loading dose calculation

Loading dose = (Vd × target plasma concentration) / F. It rapidly achieves therapeutic levels when the volume of distribution and target concentration are known.

Therapeutic index

TI = TD50 / ED50, the ratio of toxic to effective dose. A low index indicates a narrow margin of safety requiring careful monitoring.

Competitive antagonism effect

A competitive antagonist shifts the agonist dose–response curve to the right without reducing maximal response. Higher agonist concentrations can overcome the block.

Zero-order elimination

A constant amount of drug is eliminated per unit time regardless of concentration. Phenytoin and ethanol are examples; small dose increases can cause toxicity.

First-pass metabolism

Hepatic metabolism of an orally absorbed drug before it reaches systemic circulation. It reduces oral bioavailability and is bypassed by IV or sublingual routes.

Warfarin monitoring

Warfarin inhibits vitamin K epoxide reductase, reducing clotting factor synthesis. Its effect is monitored with the INR, targeting a range set by indication.

Lipinski Rule of Five

Predicts oral drug-likeness: molecular weight ≤500, logP ≤5, hydrogen-bond donors ≤5, acceptors ≤10. Two or more violations suggest poor oral absorption.

Prodrug concept

An inactive derivative requiring biotransformation to release the active drug. Enalapril is converted to enalaprilat; codeine is converted to morphine by CYP2D6.

Phase II metabolism

Conjugation reactions such as glucuronidation, sulfation, and acetylation that add polar groups. They generally increase water solubility and facilitate excretion.

Bioisosteric replacement

Substituting a functional group with a structurally similar one that retains activity. Examples include replacing –COOH with tetrazole to alter pKa and metabolism.

Enantiomer activity difference

Enantiomers are mirror-image isomers with different three-dimensional arrangements. They may differ in receptor affinity, potency, and metabolic fate.

Therapeutic drug monitoring indications

Used for drugs with narrow therapeutic index and clear concentration–effect relationships, such as digoxin, lithium, vancomycin, and phenytoin.

SOAP note format

A structured documentation method with Subjective, Objective, Assessment, and Plan sections. It organizes clinical findings and therapeutic decisions for patient care records.

Medication reconciliation

A process of obtaining the best possible medication history, comparing it with current orders, resolving discrepancies, and communicating at care transitions.

Drug therapy problems

Categories include indication, effectiveness, safety, and adherence issues. Each requires a specific pharmacist intervention and follow-up plan.

Alligation method

Combines two strengths to make a target concentration. The ratio of parts equals (higher % − desired) : (desired − lower %).

Dilution equation

C1V1 = C2V2 relates initial and final concentrations and volumes. It is used to calculate the volume of stock solution needed for a dilution.

IV drip rate

Drops per minute = (volume in mL × drop factor in gtt/mL) / time in minutes. Common drop factors include 15, 20, and 60 gtt/mL.

Mosteller body surface area

BSA (m²) = √[(height in cm × weight in kg) / 3600]. It is used to calculate pediatric and oncology doses based on surface area.

Sodium chloride equivalent

The E-value is the amount of NaCl equivalent to 1 g of drug in tonicity. NaCl equivalent = drug weight × E; used to make isotonic solutions.

Schedule II refill limits

Schedule II controlled substances generally cannot be refilled without a new prescription. Schedule III–IV products allow limited refills per jurisdiction, commonly five within six months.

Prescription legal requirements

A valid prescription includes prescriber identity and license number, patient details, drug name, strength, dosage form, quantity, directions, and date with signature.

Pharmacist ethical principles

Core principles include beneficence, non-maleficence, autonomy, justice, veracity, and confidentiality. They guide decisions when duties to patients conflict.

Generic substitution rule

Substitution with a bioequivalent generic is generally permitted unless the prescriber prohibits it or the patient refuses. Local law defines specific requirements.

Cardiac glycoside mechanism

Digitalis glycosides such as digoxin inhibit Na+/K+-ATPase, increasing intracellular calcium and enhancing cardiac contractility. They have a narrow therapeutic index.

St John's wort interaction

St John's wort induces CYP3A4, reducing plasma levels and efficacy of oral contraceptives, warfarin, and some antiretrovirals. It also risks serotonergic interactions.

Incidence versus prevalence

Incidence counts new cases in a population at risk over time. Prevalence counts all existing cases in the population at a given point or period.

Sensitivity and specificity

Sensitivity = TP/(TP+FN), the ability to detect true disease. Specificity = TN/(TN+FP), the ability to correctly identify those without disease.

Herd immunity threshold

Approximated as 1 − 1/R0, where R0 is the basic reproduction number. Higher R0 requires higher vaccination coverage to interrupt transmission.

Incremental cost-effectiveness ratio

ICER = (Cost new − Cost old) / (Effect new − Effect old). It expresses the additional cost per additional unit of health outcome gained.

Economic order quantity

EOQ = √(2DS/H), where D is annual demand, S is ordering cost, and H is holding cost per unit. It minimizes total ordering and holding costs.

ABC inventory analysis

Classifies stock items by annual value, with A items being high-value and few. It prioritizes control efforts on items with the greatest financial impact.