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Pharm Quiz 1
Dr. GIllis lectures for quiz 1
34
Nursing
Undergraduate 2
11/25/2012
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Term
Definition of a Drug
 Definition
Any chemical that can affect living
processes.
• Lehne, R.A. (2010). Pharmacology for nursing care (7
th
ed.).
St. Louis, MI: Saunders Elsevier.
 A substance that brings about a
change in biologic function
through its chemical actions.
Term
Objective of Drug Therapy
 Definition
Provide maximal benefit with minimal harm.
Term
Properties of an Ideal Drug
 Definition
 Effectiveness
 Safety
 Selectivity
 Reversibility
 Predictability
 Ease of administration
 Minimal drug interactions
 Cost effective
Term
Three common ways that drugs are named
 Definition
Chemical names (N-acetyl-p-aminophenol, APAP)
 Generic names (acetaminophen)
• Non-proprietary or common name
 Trade names (Tylenol)
• Proprietary or brand name

*** Note that generic names start with a small letter and trade names
start with a capital letter.
Term
Benefits of using generic drug names in hospital
 Definition
• Potentially* less confusion
• E.g. Celebrex (celecoxib) & Celexa (citalopram)
• Lower cost than brand names
 More consistent
• can be numerous brand names for one drug
 Help to identify group to which drug belongs
• Drugs in same category often share similar
properties
• “-pril”, “-olol”, “sartan”,
Term
Clinical Pharmacology Definition
 Definition
 Pharmacology (study of drugs and their
interactions with living systems) in
humans
Term
Pharmacotherapeutics Definition
 Definition
The use of drugs to:
diagnose, prevent, treat a disease
Term
Pharmacokinetics vs Pharmacodynamics
 Definition
Pharmacokinetics
• “What the body does to the drug”
• Absorption, distribution, metabolism, excretion
•“ADME”
 Pharmacodynamics
• “What the drug does to the body”
• How drugs produce their pharmacologic effects
• Mechanism of action
Term
Three ways that Drugs can cross membranes
 Definition
Passage through channels or pores
• Usually for small ions or small molecular weight molecules (e.g.
potassium)
2. Passage with the aid of a transport system
• Transport pumps may or may not require energy (e.g. transport
systems in the kidney)
3. Direct penetration of the membrane (Most common)
• Passive diffusion through the membrane
• Rate of diffusion depends on many factors (Concentration gradient)
• Lipid solubility (lipophilicity essential for drugs to cross membranes)
• Polar molecules and ions – not lipid soluble and do not cross membranes
Term
Absorption - Definition
 Definition
 Movement of a drug from its site of
administration into the blood.
 Certain factors will affect the
o Rate
&
o Amount
of drug absorbed
Term
Two broad factors that affect absorption
 Definition
Drug properties – physical & chemical
 Site properties – anatomic & physiologic
Term
5 Specific factors that affect Drug absorption
 Definition
Rate of dissolution
 E.g. tablets - rapid dissolution could yield more rapid onset
 Surface area
 Larger surface area, more drug likely to be absorbed
 Blood flow
 More absorption when blood flow is high
 E.g. insulin (do not massage injection site)
 Lipid solubility
 More lipid soluble more readily absorbed
 Recall the phospholipid bilayer
 pH partitioning
 ASA ion trapping example in your book
Term
Bioavailability Definition
 Definition
Also called F Value

the fraction of unchanged drug
reaching the systemic circulation after
administration by any route
usually indicated as %
Term
Bioavailability: Why might F be less than 100%?
 Definition
Examples (oral):
• Inactivation or destruction in stomach (e.g insulin)
• binding/chelating interactions with drugs (iron and
dairy)
• metabolism in lining of gut, first pass effect
(ETOH)
• malabsorptive syndromes
• pH, gastric emptying, GI mobility
• vomiting, etc.

**First pass is an important concept
Term
Drug Distribution - Definition and 3 major factors
 Definition
Movement of drugs throughout the body

1. Blood flow to tissues
o Problem conditions – abscesses, tumours
2. Exiting the vascular space
o capillary beds – drugs pass between capillary cells.
o BBB - tight junctions in capillary beds
o Drugs – pass through - need lipid solubility or
transport pump
o protein binding - bound and free drug
3. Entering cells
o Enter cells for metabolism and excretion & for some,
in order to have action
Term
Metabolism - Definition, Where most of it occurs
 Definition
Enzymatic alteration of drug structure by the
microsomal enzyme system (Cytochrome P450)
  We will abbreviate CYP450
 Most drug metabolism occurs in the liver
 Other organs do take part
 Lung
 Lining of the GI
 kidney
Term
Definition of Inducer and Inhibitor in reference to CYP450
 Definition
Drugs metabolized by an enzyme are called
SUBSTRATES for that enzyme.
o Drugs that inhibit the actions of a particular enzyme
are called enzyme INHIBITORs.
o Drugs that increase the number of CYP450 enzymes
are called an enzyme INDUCER.
Term
5 consequences of Metabolism
 Definition
Accelerated renal drug excretion
2. Drug inactivation
3. Increased therapeutic action
4. Activation of prodrugs
5. Increased or decreased toxicities
Some drugs are highly metabolized by the liver –
“high first pass effect”
Term
first pass effect: how to avoid it
 Definition
Ways to avoid:
•Sublingual and IV routes
• passages directly into systemic (not portal) circulation
e.g. nitroglycerin and morphine have high first pass effects.
•Prodrugs
• Codeine (methylmorphine) –demethylation to morhine
+ methyl group
Necessary dose conversions:
•Explains IV to PO conversions of drugs
 higher oral dose often necessary due to first pass effect
Term
Why do we need to know how much of a drug is renally elimminated? How is the drug dose adjusted to compensate for differences in kidney function?
 Definition
Why does this matter? What happens when the kidneys are
not functioning normally?
 Consider the potential consequences of drug accumulation
 E.g. narrow vs non-narrow therapeutic index/range drugs.
 E.g. side effects more pronounced – sulfonylureas
 A drug is primarily eliminated by the kidneys when the renal
route accounts for > 50% of the drug’s elimination
 Clinically
 Dose adjust based on Creatinine Clearance and
guidelines
Term
6 Non-renal routes of elimination
 Definition
 Breast milk
 Bile
 Lungs
 Sweat
 Saliva
 Feces
Term
Steady State (plateau) - How long does it take to reach?
 Definition
 Drug given repeatedly at the same dose
usually takes 4-5 half lives to get to a
steady state concentration.
 book says 4, some give range of 4-5 we will use 5
for testing and discussion but recall in practice
people could use a range!

Regardless of the dosage size, the time
required to reach plateau is the same
Term
Loading Doses - What is the purpose?
 Definition
To achieve a more rapid steady state
concentration of the maintenance dose
Term
Four Receptor Families
 Definition
1.Cell membrane embedded enzymes
2.Ligand-gated ion channels
3.G-protein coupled receptor
4.Transcription factors
Term
Receptor Selectivity: What do we want in a good target for drug therapy
 Definition
 Limited number of
functions
 Drug interacting with
many versus limited
receptors
 Some single receptors
regulate several
physiologic effects
 Can’t always guarantee
safety
 e.g. in Lehne is morphine
 Since certain receptor classes
can produce several effects
 Morphine
 pain relief
 other “unwanted” or side effects
can occur
 respiratory depression
 constipation
Term
Drug-Receptor Interaction: Single vs Modified Occupancy Theory
 Definition
Affinity –the strength of attraction between a
drug and its receptor
 High affinity = high potency
 Intrinsic activity –the ability of a drug to
activate a receptor upon binding
 High intrinsic activity =maximal efficacy
Term
Maximal Efficacy Definition
 Definition
Largest effect that a drug can produce
Term
Potency Definition
 Definition
Refers to the amount of drug we must give to
elicit an effect
Term
Definition of Receptor Agonist
 Definition
Agonist:
 Medications that mimic the body’s own
regulatory molecules to activate
receptors
 Note “activate” ≠ speeding up
processes! Agonists can also act to
slow processes
 affinity and high intrinsic activity
Term
Definition of Receptor Antagonist + Two categories
 Definition
 Drugs that prevent the activation of receptors
by endogenous regulators and drugs
 Antagonists - “no effects” on their own on
receptor function
 effects produced are a result of blocking
receptors from agonists!!
 affinity for receptor but no intrinsic activity

Competitive
 reversible binding
 compete with
agonists for binding
sites
 to overcome
antagonism
 increase agonist
concentration

Noncompetitive
 irreversible binding
 key ‘welded’ in lock
 to overcome
antagonism
 new receptors must
be made
Term
what factors influence the response to competetive antagonists
 Definition
The response to an antagonist is determined
by the amount of agonist present and their
affinity for the receptor
 If the agonist and antagonist have equal
affinity the receptors will be occupied by
whichever agent is present in the highest
concentration
Term
Partial agonist definition
 Definition
 produce a lower maximal response,
even at full receptor occupancy
 Affinity yet only moderate intrinsic
activity
Term
Drug responses that do not involve receptors
 Definition
 Act through physical or chemical interactions
 Antacids
 Antiseptics –(ethyl alcohol)
 Laxative (PEG, mag sulfate)
Term
4 major types of drug interactions
 Definition
 Drug – drug
 Oral contraceptives and St. John’s Wort (M)
 Probenecid and penicillin (E)
 Drug – food
 Grapefruit juice and simvastatin (Zocor) (M)
 Drug – disease
 Beta blockers in patients with asthma
 Cachexia with highly protein bound drugs* (D)
 CHF and drugs with mineralocorticoid effects
 Drug – laboratory
 Efavirenz (Sustiva) and marijuana testing
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