Key Terms

Therapeutic window/range

Blood concentration that produces effect without toxicity

Toxicity

Quantity that no longer gives intended response and produces toxic signs

Peak effect

Point of maximum therapeutic effect

Subtherapeutic

Dose/concentration lower than usually prescribed to treat effectively

Duration of action

How long a drug remains effective after administering

Onset of action

Time to begin producing intended effect

First pass effect

Oral drug metabolized by liver to useable form, directly influences bioavailability

Half-life

Time for concentration to decrease by half

Loading dose

Higher than usual dose so critical concentration is reached sooner

Dynamic equilibrium/steady state

• Actual amount reaching body

• Affected by ADME and biotransformation

Hypersensitivity reaction

Antibodies form to drug causing an immune response

Idiosyncratic reaction

• rare

• Can be life-threatening (organ failure/death)

• Not related to duration or dose

Receptor

Extra/intracellular proteins that mediate drug activity

Drugs can…

• directly/indirectly stimulate a receptors activity

• Block/inhibit receptor activity

• Interact with receptors on mutated/foreign cells to interfere with function

• Replace/substitute missing chemicals

Affinity

Strength of attraction between drug and receptor

Intrinsic activity

Ability to cause an effect once bound

Efficacy

Max response achieved

Agonist

Affinity + intrinsic activity

Partial agonist

Affinity + intrinsic activity but lacks full efficacy

Antagonist

Affinity but no intrinsic activity