Introduction to Pharm Flashcards

1
Q

Pharmacogenetics

A

Genetic influences by and on drugs

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2
Q

Pharmacodynamics

A

Physiological and biochemical mechanism of action of drugs (what the drug does to the body)

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3
Q

Competitive vs noncompetitive drug binding

A

Competitive: Reversible, most drugs
Noncompetitive: Nonreversible (ex: Aspirin)

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4
Q

ED50

A

Effective dose in 50% of the population

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5
Q

TD50

A

Toxic dose in 50% of the population

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6
Q

LD50

A

Lethal dose in 50% of the population

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7
Q

LD50/ED50

A

Therapeutic index

  • Safety measure of drug
  • Higher number = better
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8
Q

TD50/ED50

A

Therapeutic window

  • Estimation of drug dose that can treat disease effectively while staying in safety range (minimal toxicity/side effects)
  • Ratio between minimum effective concentration to minimum toxic concentration
  • “Margin of safety”
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9
Q

Strongest chemical bond type -> weakest (5 of them)

A

Covalent, usually is irreversible

Then ionic, hydrogen, hydrophobic, van der waals

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10
Q

4 things a dose response curve lets your determine

A
Affinity/potency 
-How much drug is needed/attraction of drug to receptor
Efficacy
-Can the drug produce 100% of the desired effect?
Variability
-Difference in living things
Slope
-Measures the margin of safety/toxicity
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11
Q

ED99

A

Effective dose in 99% of the population

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12
Q

Down-regulation

A

Caused by continued stimulation of cells with agonists, leads to desensitization
-Effect that follows continues or subsequent exposure to the same concentration of drug is diminished

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13
Q

Up-regulation

A

Caused by chronic administration of antagonists

  • Number and sensitivity of receptors increase when they’re chronically blocked
  • Results in tolerance-higher doses of antagonist are needed to counteract increasing receptor number
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14
Q

Addition effect of drugs

A

Combined effect of 2 drugs via the same mechanism is equal to what’s expected by adding their individual actions (1+1=2)

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15
Q

Synergism effect of drugs

A

The combined effect of 2 drugs is greater than the algebraic sum of their individual effects (1+1=3)

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16
Q

Potentiation effect of drugs

A

The enhancement of the action of one drug by a second drug that has no detectable action of its own (1+0=3)

17
Q

Antagonism effect of drugs

A

The action of one drug opposes the action of another (1+1=0)

-Reversal drugs

18
Q

Bioavailability definition in drug administration

A

The percentage of drug contained in a drug product that enters the systemic circulation in an unchanged form after administration of the product

  • IV: 100%
  • Inhalation: 5-<100%
  • Oral: 5-<100%, first-pass effect may be significant
19
Q

pKa

A

Ionization constant of a chemical compound, pH at with the drug will exist in solution as 50% ionized and 50% non-ionized
-Measures the extent of ionization (not acid/base status)

20
Q

General absorption of non-ionized drug

A
  • Lipid soluble
  • Can be absorbed through GI
  • Can cross placenta and blood brain barrier
21
Q

General absorption of ionized drug

A
  • Water soluble

- Can’t get through phospholipid bilayer to be absorbed GI/placenta/BBB

22
Q

pH-pKa=0

A

50/50 ionized/non-ionized

23
Q

pH-pKa=0.5

A

75/25 ionized/non-ionized

24
Q

pH-pKa>1

A

99/1 ionized/non-ionzed

25
Determining ionized vs nonionized percentage
``` Acids -In acidic pH: Non-ionized -In basic pH: Ionized Bases -In acidic pH: Ionized -In basic pH: Non-ionized ```
26
Drug metabolism: Phase 1 vs 2 reactions
``` Phase 1 -Oxidation -Reduction -Hydrolysis Phase 2 -Conjugation -Synthesis ```
27
Conjugation metabolism
Coupling the drug molecule to an endogenous substituent group so it has more water solubility - Leads to enhanced renal or biliary elimination - Catalyzed by phase 2 drug-metabolizing enzymes
28
1st pass metabolism (and effect of grapefruit juice)
After the oral administration of a drug - Absorbed drugs to go liver before systemic circulation - Decreases their bioavailability - Grapefruit juice inhibits CYP3A enzymes-increases the bioavailability of the drug
29
Enzyme induction and inhibition
Induction -Process when drugs, environmental chemicals, air pollutants, and components of cigarette smoke stimulate the synthesis of drug-metabolizing enzymes -May elevate the level of hepatic drug-metabolizing enzymes Inhibition -Opposite of ^ -Results in less metabolism of drugs, increasing their effects
30
Ionized drugs that are taken orally (metabolism)
Not absorbed well, may not be metabolized by the liver to a significant extent -Instead are commonly excreted via the renal system
31
Main factors (2) that determine the rate of drug passive diffusional transfer across membranes
Lipid solubility of the drug Concentration gradient (Molecular weight is less important than ^)
32
Protein binding (bond strength, proteins, examples where its significant)
- Influences how a drug is distributed - Protein-bound drug isn't free to act on receptors - Proportional to its lipid solubility (more lipid soluble=highly protein bound) - Bond between drug and protein is usually weak - Proteins=albumin (most common), AAG - >90% protein bound drugs=warfarin, phenytoin, propranolol, Propofol, fentanyl, diazepam (intensification of their effects if they're displaced from plasma proteins)
33
Beta half-life
AKA Elimination half-life - Time necessary for the plasma content of a drug to drop by half - Drug is fully eliminated when 95% of it has been eliminated from the body (4-5 half-lives)