Quantitative Analysis of Drug-Receptor Interactions (C.I. Valencia, MD)

Question 1

T/F: Pharmacokinetics deals with “dose”, while pharmacodynamics deals with “concentration”.

Answer 1

True

Question 2

What is the cardinal rule in Pharmacology?

Answer 2

You cannot create a new drug effect. You can only alter cellular function. Drugs are simply modulators.

Question 3

What does drug molecule-receptor binding lead to?

Answer 3

Enhancement, inhibition or blockade of molecular signals

Question 4

T/F: Clinical effects are only those we can observe with our five senses.

Answer 4

True

Question 5

How do you know how much of a drug you need to achieve a certain effect?

Answer 5

Look at the dose-response relationship.

Question 6

Enumerate the three most important properties of a drug

Answer 6

Efficacy
Safety/Lack of Toxicity
Quality

Question 7

T/F: More is always better in terms of bioavailability

Answer 7

False

Question 8

Differentiate generics and innovators

Answer 8

Generics usually have a dirty synthetic pathway but are cheaper than innovators.

Question 9

How many % of drug actions are not mediated through receptors?

Answer 9

10%

Question 10

T/F: Mannitol and acetylcystein are example of receptor-mediated drugs.

Answer 10

False

They are not.

Question 11

What drugs do not bind to receptors?

Answer 11

Antacids
Osmotic diuretics
Acid-base reactions

Question 12

T/F: A dose does not necessarily translate to an effective drug concentration.

Answer 12

True

Question 13

How does the ligand interact with its receptor?

Answer 13

Lock-and-key fashion

Question 14

What is the property that pertains to the orientation of the receptor in three-dimensional space?

Answer 14

Stereospecificity

Question 15

What are the four types of protein receptors?

Answer 15

1. Receptors for endogenous regulatory ligands
2. Enzymes of metabolic pathways
3. Enzymes in transport processes
4. Structural proteins

Question 16

What determines differences in drug effects in different tissues?

Answer 16

1. Drug properties
2. Receptor properties
3. Tissue properties

Question 17

Define: enantiomers

Answer 17

These are non superimposable mirror images of the same substance.

Question 18

Describe: Erasomate

Answer 18

1. Sold as an anti-parasitic

2. Made up of levamisol (-) and teramisol (+)

Question 19

Describe: Stirizine

Answer 19

Antihistamine

Question 20

Describe the up regulatory effect of propanolol

Answer 20

It is a beta adrenergic antagonist that lowers blood pressure. Next dosage has a greater effect.

Question 21

Describe the down regulatory effect of sulfonylurea

Answer 21

Overstimulation of agonists in the pancreas leads to decreased efficacy of the drug.

Question 22

What is the effect of opium analgesics on the brain?

Answer 22

Stimulates mu, delta and kappa receptors leading to analgesia

Question 23

Give an example of a covalent interaction between drug and receptor.

Answer 23

Acetyl group of ASA and cyclooxygenase

Question 24

What are the chemical forces involved in drug-receptor interaction?

Answer 24

Covalent bonds
Electrostatic
Hydrophobic bonds

Question 25

What is the inactive form of ampicillin?

Answer 25

Pivampicillin

Question 26

What are the types of dose response curves?

Answer 26

Graded Response Curve | Quantal Response Curve

Question 27

What is the shape of the non-logarithmic graded response curve?

Answer 27

Hyperbolic

Question 28

T/F: The central portion of the sigmoid graded response curve is nearly linear.

Answer 28

True

Question 29

What do you call the highest intensity of effect a drug can achieve?

Answer 29

Efficacy

Question 30

Why is there variability in the dose response curve?

Answer 30

It depends on the person, age, weight, clearance effect, dose, etc.

Question 31

Describe steep and gradual dose response curves.

Answer 31

Steep: cobra ready to bite Gradual: resting Buddha

Question 32

Give the formula for therapeutic index

Answer 32

Therapeutic Index = LD50/ED50

Question 33

In the presence of a competitive antagonist, the response curve is shifted to the?

Answer 33

Right

Question 34

Describe: Maximal effect

Answer 34

Point at which a drug's effect plateaus even with continued increase in dose

Question 35

Differentiate efficacy and potency

Answer 35

Efficacy - effect of drug irrespective of dose | Potency - effect of drug with respect to dose

Question 36

Potency is determined by what variable?

Answer 36

EC50 or ED50

Question 37

If a drug expires, what happens to its potency?

Answer 37

It will degrade.

Question 38

T/F: Dose is dependent on the smallest concentration available.

Answer 38

False It is dependent on what is feasible to be taken in by humans.

Question 39

T/F: Potency is not an important factor.

Answer 39

True

Question 40

T/F: You should always choose a drug that is more potent than efficient.

Answer 40

False It should be more efficient. We don't care about potency.

Question 41

Describe: Quantal Response Curve

Answer 41

All or none event | Concentration vs. number responding

Question 42

What do you call patients who respond to a small dose of a drug?

Answer 42

Sensitive

Question 43

What do you call patients who only respond to high concentrations of a drug?

Answer 43

Tolerant

Question 44

T/F: Not all persons will manifest with a positive quantal response at the same drug concentration due to variation.

Answer 44

True

Question 45

How many % of respondents will respond to a median dose of the drug?

Answer 45

68%

Question 46

What are quantal dose curves used for?

Answer 46

Generating the margin of safety for a particular drug

Question 47

Enumerate the different examples of non-receptor drug action

Answer 47

1. Acid-base neutralisation 2. Colligative effects in the bronchi (acetylcysteine-initiated breakage of disulphide bonds) 3. Counterfeit incorporation mechanism (purine and pyrimidine analogs in cancer treatment) 4. Osmolality effects in the brain (mannitol and brain)

Question 48

T/F: Therapeutic index = margin of safety

Answer 48

True

Question 49

What is the desirable margin of safety?

Answer 49

100 - 1000

Question 50

What harmful effects can phenobarbital cause?

Answer 50

Apnea and coma

Question 51

Is diazepam a safe sedative?

Answer 51

Yes

Question 52

T/F: TIs of 5 and below indicate drugs with relatively greater potential for toxicity.

Answer 52

False Statement is true for TIs of 4 and below.

Question 53

Describe the mechanism of action of azoles

Answer 53

They possess a heterocyclic ring with sulfur and nitrogen inside, which is used against amoeba and fungi.

Question 54

Describe: citrizine

Answer 54

1. Drug used to treat colorectal cancer | 2. Possesses a combination of L-citirizine and D-citirizine

Question 55

What is the phenomenon that occurs when the diagnostic, preventive and therapeutic action of a drug is modified or altered by another drug when administered concomitantly?

Answer 55

Drug interaction

Question 56

What are the quantitative aspects of pharmacodynamic drug interactions?

Answer 56

1. Synergism/potentiation 2. Addition 3. Inhibition

Question 57

What causes pharmacokinetic drug interactions?

Answer 57

Alterations to ADME

Question 58

What are the clinical classifications of drug interactions?

Answer 58

1. Beneficial | 2. Adverse

Question 59

What are the requirements of rational therapy?

Answer 59

1. Diagnostic certainty 2. Pathophysiological understanding 3. Pharmacological understanding 4. Optimal drug & dose administration 5. Picking efficacy/toxicity end points and monitoring 6. Open communication and willingness to alter regimen

Question 60

Enumerate the factors that affect therapeutic outcomes

Answer 60

1. Age 2. Drug-drug interactions 3. Fixed-dose combination 4. Placebo effects 5. Tolerance 6. Genetic factors

Question 61

Enumerate the factors that contribute to lack of efficacy

Answer 61

1. Misdiagnosis 2. Poor compliance 3. Poor choice of dosage 4. Development of separate illness 5. Use of other drugs 6. Undetected genetic/environmental variables 7. Unknown therapy by another physician