Intro to Pharmacology Flashcards
1
Q
Relevance to physical therapy
A
- older populations
- polypharmacy (inappropriate use)
- noncompliance
- adverse drug reactions (ADRs)
- opioids
- communication
- hospital readmissions
- interactions with exercise
- rural health, in-home health
- electronic medical record (EMR) updates
- education
- scheduling of visits
2
Q
APTA roles & responsibility of a physical therapist
A
-patient management integrates an understanding of a pt’s prescription & nonprescription medication regimen with consideration of its impact on: health, function, movement, & disability
- it’s within our scope to administer & store medication to facilitate outcomes of PT patient management
3
Q
Define pharmacology
A
- the study of drugs
- very broad term
4
Q
Define pharmacotherapeutics
A
- use of drugs to prevent, treat, or diagnose, a disease
5
Q
Define pharmacokinetics
A
- what the body does to the drug/how the body handles the drug
- ADME: absorption, distribution, metabolism, excretion
6
Q
Define pharmacodynamics
A
- what the drug does to the body
- effect of the drug
7
Q
Define toxicology
A
- study of harmful effects of chemicals/drugs
- not just a subspecialty of pharmacology
8
Q
Define pharmacogenetics
A
- genetic basis for drug responses
- area of great study & advancement
- “personalized medicine”
9
Q
Describe the drug approval process
A
- Preclinical testing: 1-2 yrs, lab animals, used to determine drug effects & safety
- Phase I: <1 yr, <100 healthy volunteers, determine effects, safe dosage, & pharmacokinetics
- Phase II: 2 yrs, 200-300 targeted patients with disorder, assess drug effectiveness in treating specific disease
- Phase III: 3 yrs, 1,000-3,000 targeted patients, assess safety & effectiveness in larger pt pop.
- Phase IV (postmarketing surveillance): indefinite, general pt pop., monitor any problems that occur after NDA approval
10
Q
Describe orphan drugs
A
- drugs for treatment of rare diseases: <200,00 people in US
- difficult research
- costly
- additional funding available
11
Q
Describe the different drug names
A
- Brand name: trade name, marketing/commercials, can always look this up (ex: Tylenol)
- Generic name: widely accepted (ex: acetaminophen)
- Chemical name: frequently associated with the structure, preclinical trials, generally long & cumbersome (ex: N-acetyl-p-aminophenol (APAP))
12
Q
Define pharmaceutical equivalents
A
- drug products that contain the same active ingredients & are identical in strength or concentration, dosage form, & route of administration
13
Q
Define bioequivalent
A
- rates & extents of bioavailability (F) of the active ingredient in the two products are not significantly different
14
Q
Describe over the counter (OTC)
A
- treat relatively minor problems
- safe for use without direct medical supervision
- low risk of toxicity
15
Q
Describe “behind the counter” medications
A
- have to speak to a pharmacist but could get without a prescription
- Examples: insulin, schedule V cough syrups, pseudoephedrine, emergency contraceptives
16
Q
Describe off-label prescribing
A
- use of a medication to treat a condition other than what it was originally approved to treat
- practitioners subjected to increased scrutiny if serious adverse effects
17
Q
Grading of controlled substances
A
- Schedule I: no current accepted medical use (LSD, heroin)
- Schedule II: high potential for abuse (oxycodone)
- Schedule III: some potential for abuse (<90mg of codeine with APAP)
- Schedule IV: lower potential for abuse (benzodiazepines)
- Schedule V: even less potential for abuse (cough preparations with codeine)
18
Q
Describe the parts of the Dose-Response Curve
A
- Threshold dose: minimum dose to elicit effect
- Ceiling effect: maximal effect (no more effect if take more)
19
Q
Define potency
A
- related to the dose that produces a given response in a specific amplitude
- the more potent drug requires a lower dose to produce the same effect
20
Q
Describe the therapeutic index
A
- Therapeutic index = toxic dose ÷ effective dose
- ED 50 = median effective dose at which 50% of pop responds to the drug
- TD 50 = median toxic dose at which 50% of the group exhibits the adverse effect
- LD 50 = median lethal dose that causes death in 50% of the pop (animals)
21
Q
Describe the differences between narrow vs wide therapeutic index
A
- Narrow: difference between effective & toxic doses is small
- the greater the TI (toxic index) the safer the drug
- close monitoring required for narrow therapeutic index drugs
- Examples: Carbamazepine, Phenytoin, & Tacrolimus
22
Q
What are the different routes of administration
A
- Enteral (into the GI tract): oral (sublingual = under tongue & buccal = in the cheek), rectal, or via tube
- Parenteral (other than GI tract): injection (intravenous/IV = into vein, intramuscular/IM = into muscle, intradermal/ID = into dermis, subcutaneous/SC/SQ = under the skin, intraperitoneal/IP = into the peritoneum, intrathecal = into the spine), inhalation, topical (local effect), or transdermal (systemic effect)
23
Q
What does erratic distribution mean
A
- means the drug can be well absorbed in one person and not as well absorbed in another person
24
Q
Describe first pass effect/metabolism
A
- after being given orally the drug is transported directly into the liver via the portal vein where a significant amount of the drug can be metabolized prior to reaching its site of action
- buccal or sublingual administration avoids first pass metabolism
25
Q
Describe bioavailability (F)
A
- the extent a drug reaches the systemic circulation
- IV administration = 100% F
- Example of 50% F: 100mg taken orally & only 50mg reaches systemic circulation
- Example: loop diuretics
26
Q
Distribution of a drug in the body is related to what
A
- tissue permeability
- blood flow
- binding to plasma proteins
- binding to sub cellular components
27
Q
Describe volume of distribution
A
-Vd = amount of drug administered ÷ concentration in plasma
- healthy 70kg man has a total body fluid of ~42L
- this allows us to confirm that the drug went to where we wanted it to
28
Q
What are the different ways a drug can move across membranes
A
- passive diffusion
- active transport
- facilitated diffusion
- endocytosis/exocytosis
29
Q
Drug storage sites
A
- Adipose: lipid soluble drugs (ex: midazolam), poor perfusion, low metabolic rate
- Bone
- Muscle
- Organs
30
Q
Describe novel drug delivery
A
- Controlled release preparations: timed release, sustained release, extended release, & prolonged action
- Implanted drug delivery systems: surgically implanted reservoir
31
Q
Describe drug elimination & drug excretion
A
- Elimination: drug metabolism (biotransformation; primarily liver: oxidation = O2 added or hydrogen removed, reduction = O2 removed or hydrogen added, hydrolysis = broken into separate parts, & conjunction = coupled to another compound
- Excretion: primarily kidney
32
Q
How does metabolism and excretion work together
A
- metabolism creates a more polar compound
- remaining ionized metabolite is more water soluble and more easily transported via the bloodstream to the kidneys (excreted in urine)
33
Q
Describe metabolites
A
- can be active and/or inactive
- some drugs have to be metabolized to be active
- prodrug: inactive form, ex: fosphenytoin
34
Q
Describe the half-life of a drug
A
- the amount of time required to decrease the concentration of a drug by 50%
- function of clearance and Vd (volume distribution)
35
Q
What can cause variations in drug response and metabolism
A
- Genetics
- Disease
- Drug interactions
- Age
- Diet
- Sex
36
Q
What is a drug receptor
A
- a component in or within a cell that a substance can bind to (any cellular macromolecule, commonly protein or protein complex)
- when a drug binds a receptor a chain of events causes a change in function of the cell
37
Q
Describe drug receptor interactions
A
- drug receptor interactions at the cellular level ultimately cause the physiological changes that we observe in our patients
38
Q
Describe drug receptor affinity
A
- the amount of attraction between a drug and a receptor
- drugs with high affinity bind readily to open receptors even at low concentrations
- drugs with lower affinity require higher concentrations in the body to occupy the receptors
39
Q
Describe drug receptor selectivity
A
- a relative term because all drugs produce some side effects however a selective drug produces fewer side effects than a consultative agent
- selective drug ex: Metoprolol (beta blocker)
- novelette drug ex: Carvedilol (alpha and beta blocker)
40
Q
Define agonists
A
- a drug that can bind to a receptor and initiate a change in the cells function
- has affinity and efficacy
- ex: Epinephrine
41
Q
Define drug efficacy
A
- indicates that the drug will activate the receptor and change the function of the cell
- as an aside we want medications with a high level of efficacy with limited safety issues
42
Q
Define an antagonist drug receptor
A
- a drug that will bind to the receptor but will not cause any direct change in the function of the receptor
- “blocks” the effect of another chemical
- has affinity but not efficacy
- example: beta blockers
43
Q
Describe competitive antagonists
A
- competes for receptor sites
- forms weak bonds
- whichever drug has the higher concentration will “win” and exert effect
- can be reversed by increasing the concentration
44
Q
Describe noncompetitive antagonists
A
- forms a permanent bond with a receptor
- will stay bound until the receptor is replaced
- effect can last several days, cannot be reversed
- example: some anti platelet medications ei. Clopidogrel
45
Q
Describe partial agonists
A
- do not evoke maximal response compared to a strong agonist
- can have high affinity
- only partially activates the recotor
46
Q
Describe mixed agonist-antagonist
A
- stimulate certain receptor subtypes and block the efffects of endogenous substances on other receptor subtypes
- example: raloxifene, estrogen receptor agonist on bone and antagonist in breast tissue; prevent and treat loss and reduce risk of invasive breast cancer
47
Q
Define drug effect
A
- what the drug is used to achieve
- therapeutic effect
48
Q
Difference between a drug side effect and an adverse drug reaction (ADR)
A
- Side effect: expected and well known reaction, predictable frequency, can be harmful or beneficial
- Adverse drug reaction (ADR): noxious/undesirable effect, unexpected, can limit therapy
- ADRs most common after hospital discharge
49
Q
Describe polyopharmacology
A
- use of multiple medications to treat one or more disease states
- medications added to treat the side effects of another medication
- adverse outcomes: mortality, falls, adverse drug reactions (ADR), increased length of stay, hospital admission
50
Q
Define deprescribing
A
- there planned and supervised process of dose reduction or stopping of medications that might be causing harm or no longer be of benefit
- part of good prescribing
51
Q
Why is deprescribing hard
A
- patients see >1 provider
- medications added by another provider
- patients may want the medications
- patients/families ultimately need to stop the medications
52
Q
Effect of exercise in pharmacokinetics
A
- increases perfusion vs decreased perfusion
- chances dependent on drug/route and exercise variables
- must consider timing of therapy in relation to medication dosing
53
Q
Effect of exercise in absorption
A
- increased tissue heat: increases kinetic molecular movement and increases diffusion across biological membranes
- increased/decreased drug dispersion away from the delivery site
54
Q
Effect of exercise in distribution and clearance
A
- Distribution: Vd (volume of distribution) can increase or decrease
- Clearance: decreased hepatic blood flow leads to decreased clearance and decreased renal blood flow
55
Q
Implications for physical therapy
A
- timing of rehab session with drug peaks and valleys
- effects on absorption and distribution: increased by heat, exercise, or massage and decreased by cold
- help recognize improper drug responses
- monitor for worsening of condition
