Intro to Pharm for PTs

Question 1

Why should PTs study pharmacology?

Answer 1

1. Drugs affect PT
2. PT affects drugs
3. PTs should be able to recognize and respond to ADRs

Question 2

Chemical Name

Nomenclature

Answer 2

refers to specific compound’s structure, long & cumbersome

Question 3

Generic Name

Nomenclature

Answer 3

derived from chemical name, somewhat shorter, non-proprietary

Question 4

Trade Name (Brand name)

Nomenclature

Answer 4

assigned to compound by pharmaceutical company for marketing purposes

Question 5

Schedule I- Classification of Controlled Substances

Answer 5

Drugs, substances, or chemicals with no currently accepted medical use and a high potential for abuse
(Heroin, LSD, Marijuana, MDMA, etc.)

Question 6

Schedule II- Classification of Controlled Substances

Answer 6

Drugs, substances, chemicals with a high potential for abuse and use potentially leading to severe psychological or physical dependence. Accepted for medical use
(Methamphetamine, Oxycodone, Morphine, Methadone, Fentanyl, Cocaine, etc.)

Question 7

Schedule III- Classification of Controlled Substances

Answer 7

Moderate or lower abuse potential compared to II drugs
(Anabolic steroids, testosterone, codeine, ketamine, etc.)

Question 8

Schedule IV- Classification of Controlled Substances

Answer 8

Lower abuse potential compared to III drugs and lower risk of dependence
(Diazepam, Lorazepam, Phenobarb, Tramadol, etc.)

Question 9

Schedule V- Classification of Controlled Substances

Answer 9

Lowest abuse potential
(Low dose opioids in cough meds, lamotil, pregabalin, etc.)

Question 10

What is a drug?

Answer 10

Chemical substance is main ingredient

Question 11

Bio-equivalence

Answer 11

Generic drug forms as safe and effective as og brand name if:
1. generic drug undergoes testing to establish same active ingredients, pharmokinetic profile, administration route, and therapeutic effects
If criteria not met, can only assume substitution of generic drug for brand name will only produce similar effects

Question 12

How can drugs affect therapy sessions?

Answer 12

1. By hindering therapy (i.e. impairing cognition or motor function)
2. By facilitating therapy (i.e. pain management)
3. By contributing to pt safety (i.e. respiratory medications)

Question 13

Pharmacology

Answer 13

Pharmacotherapeutics (Pharmacokinetics and Pharmacodynamics) and Toxicology

Question 14

Pharmacokinetics (PK)

Answer 14

What the body does to the drug
* A- absorption
* D- distribution
* M- metabolism
* E- excretion

Question 15

Pharmacodynamics (PD)

Answer 15

What the drug does to the body
* MOA
* Dose response (efficacy, potency, therapeutic index)
* Effectts
* Side effects aka ADR

Question 16

Bioavailability definition

Answer 16

• amount of drug that can gain access to systemic circulation
• parameter expressed as % of drug adminstered that reaches blood stream
• impacted by absorption (stomach acidity, gastric emptying, surface area, GI enzyms, developmental changes)

Question 17

Bioavailability depends on

Answer 17

• Route of adminstration
• Drugs ability to cross membrane barriers (active, passive, facilitated, special processes)

Question 18

Factors affecting drug distribution

Answer 18

• Tissue permeability
• Blood flow
• Plasma proteins binding
• Subcellular components binding

Question 19

Where are drugs stored when distributed?

Answer 19

Adipose, bone, muscle, organs

Question 20

What is volume of distribution (Vd)

Answer 20

Ratio expressing amount of drug adminstered/concentration of drug in plasma

Question 21

Metabolism of drugs

Answer 21

• Metabolite formation
• Biotransformation by liver via Cytochrome P450 (CYP) and others
• Cellular mechanisms

Question 22

CYP-Induction and CYP-inhibition

Answer 22

CYP induction= increase enzyme levels –> increased metabolism of drugs –> decrease effects of drug

CYP inhibition= decrease enzyme levels –> decrease metabolism of drugs –> increase effects of drug

Question 23

Drug elimination/excretion rates

Answer 23

Kidneys/nephron is major site of drug elimination
* Clearance- ability of organs/tissues to eliminate drug
* Half life- amount of time required for 50% of drug remaining in body to be eliminated (usually 5-7 half lives for complete eliminate)

Question 24

Half life example Q

Half life is 4 hours, how much time to remove drug from body? Until how many hours after taking drug is it still effective?

Answer 24

100mg 0hr –> 50mg 4h –> 25mg 8h –> 12.5mg 12h –> 6.25mg 16h –> 3.12mg 20h –> 1.56mg 24h –> 0.78 28h

28h/4= 7 half lives until drug is eliminated. Drug is still detectable and effective at 24 hours.

Question 25

What variations affect drug response

Answer 25

1. Genetics
2. Disease (esp liver/kidneys)- hepatic dysfunction can significantly alter drug metabolism
3. Age
4. Diet
5. Gender
6. Drug Interactions
7. Other (Environmental, cigarettes, alcohol, obesity, exercise, injuries)

Question 26

Pharmacodynamics depends on…

Answer 26

Depends upon drug receptors and ability of drug to bind to receptors

Question 27

Dose Response Curves

Answer 27

Provides information about dosage range over which drug is effective, provides information about peak response

Question 28

Therapeutic Index

Answer 28

TI= TD50/ED50
* Indicator of drug safety
* TD50 should be high, ED shoulde be low –> Increase TI
* > TI = > safety
* Large TI indicates a much larger dose is required to evoke toxic response than it does to cause a beneficial response

TD50: median therapeutic dose, ED50: median effective dose

Question 29

Quantal Dose Response Curves

Answer 29

ED50= Median Effective Dose, dose at which 50% of population responds to drug in specific manner
TD50= Median Toxic Dose, dose at whcih 50% of population exhibits adverse effects
LD50= Median Lethal Dose, dose at which death occurs in 50% of group (animal studies)

Question 30

Receptor Types

Answer 30

• Channel linked- open channel/membrane permeability
• Enzyme linked- activates enzyme within cell
• G protein coupled receptor- linked to regulatory proteins controlling enzymatic processes, primary secondary messengers
• Intracellular- protein synthesis

Question 31

Drug selectivity

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Answer 31

Function of ability of drug to interact with specific receptors on target tissue and not with other receptors on target tissue or other tissues

Question 32

Additive Drug Effects

Answer 32

Effects of two chemicals equal to sum of effect of two chemicals taken separately (i.e. aspirin and motrin)

Question 33

Synergistic effects

Answer 33

Effect of two chemicals taken together is greater than sum of separate effect at same doses (i.e. alcohol and other drugs)

Question 34

Antagonistic Effects

Answer 34

Effect of two chemicals taken together is less than sum of separate effect at same dose