Pharmacology Practice Exam Review

A collection of vocabulary terms and definitions derived from pharmacology lecture notes and exam questions covering pharmacokinetics, pharmacodynamics, and chemotherapy.

Volume of Distribution ($V_d$)

A pharmacokinetic value used to calculate a reasonable loading dose; it is greater for drugs that concentrate in tissues rather than plasma.

Half-life ($t_{1/2}$)

The time required for the plasma concentration of a drug to decrease by $50\%$; it provides the best estimate of how long it takes for a drug to reach steady state.

First-pass Effect

The process where orally administered drugs are rapidly inactivated by hepatic enzymes or excreted in the bile, losing effectiveness during their first pass through the liver.

Phase II Biotransformation

Reactions involving the conjugation of compounds with endogenous substances such as glucuronic acid, sulfate, acetate, or glutathione; examples include glucuronidation and acetylation.

Zero-order Kinetics

Also known as saturation kinetics; a state where the absolute amount of drug eliminated per unit time is constant regardless of plasma concentration because elimination routes are saturated.

Bioavailability ($F$)

The fraction of an administered dose of unchanged drug that reaches the systemic circulation; it is equivalent to the Area Under the Curve (AUC).

Clearance ($CL$)

The volume of blood that is cleared of a drug per unit time.

Protonation

The association of a molecule with a proton or hydrogen ion ($H^+$); acids are more lipid soluble when protonated, while bases are more water soluble when protonated.

Protein Kinases

Enzymes that function to phosphorylate target proteins.

Reversible Competitive Antagonist

An agent that competes with an agonist for the same receptor site, increasing the agonist's $ED_{50}$; its effects can be overcome by giving a higher dose of the agonist.

G Protein (Inactive State)

The state of a G protein when a molecule of guanosine diphosphate (GDP) is attached to its alpha subunit.

Atropine

A muscarinic site antagonist used for dilating the pupil and paralyzing accommodation.

Muscarinic Agonists

Drugs that can improve aqueous humor drainage in chronic open-angle glaucoma.

Glutamate

An excitatory neurotransmitter in the Central Nervous System.

Benzodiazepines

Drugs that increase the frequency of chloride ion channel opening by acting on GABA receptors.

Spare Receptors

Receptors that may be detected when the $EC_{50}$ is less than the $K_d$ for the agonist; they are identical to nonspare receptors but are in excess of what is needed to produce a maximal effect.

Arginine

An amino acid that serves as a precursor to nitric oxide.

Beta Lactams

A class of antibiotics that work by inhibiting polymer cross-linking in the bacterial cell wall.

Amantadine

An antiviral drug that inhibits proton influx through the endosomal $M2$ channel.

Macrolides

Antibiotics that bind to the bacterial $50S$ ribosomal subunit to block bacterial protein exit.

Topoisomerase Type I

Bacterial enzymes that snip $1$ DNA strand to assist in uncoiling.

Murein

A network of peptidoglycans that makes up a bacterial cell's wall.

Ergosterol

The major lipid found in the fungal cell membrane.

Gompertzian Kinetics

A principle stating that tumors below a critical mass point are more easily eradicated with chemotherapeutics than tumors above that point.

Echinocandins

A class of antifungal drugs that inhibits glucan synthesis, blocking the production of the major structural component of the fungal cell wall.

Selective Targeting

The principle of a drug hitting a pathogen target without affecting the host, such as trimethoprim inhibiting bacterial but not human dihydrofolate reductase.