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Flashcards in Samplex 2016 Deck (66)
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1

The following falls under the realm of medical pharmacology?

A. Use of vaccine for prevention of a disease
B. Use of drug for diagnosis of disease
C. Use of antibiotics for treatment of infections
D. AOTA

D

2

Nicotinic subunit receptor responsible for gate opening upon Ach binding

A. Alpha
B. Beta
C. Gamma
D. Delta

A

3

A patient with asthma presented with bronchoconstriction. Which drug will cause a delayed but prolonged effect?

A. Glucocorticoid on GPCR
B. Beta blocker on GPCR
C. Anticholinergic on cyto/nuclear receptor
D. Glucocorticoid on cyto/nuclear receptor

D

A and C are not likely since there GCs act on cyto/nuclear receptors while BBs and ACs act on GPCRs. BBs do act on GPCRs but the action is short and fast

4

Anesthetics that work similarly with tubocurarine induce skeletal muscle relaxation through the following

A. Inhibit exit of Na through NaCh receptor
B. Allow exit
C. Inhibiting the entry of sodium across the cell membranes of the nicotinic acetylcholine receptor
D. Allow exit

C

It inhibits ENTRY to prevent depolarization which causes muscle contraction

5

Action of mannitol is specific for this receptor:

A. Ionotrophic
B. Metabotrophic
C. GPCR
D. None of the above

D

Mannitol is non-receptor mediated. It works by exerting an osmotic effect, not by binding to receptors.

6

What effect does an allosteric activator exert on a drug?

A. Decrease the efficacy of a drug
B. Increase in the efficacy of the drug
C. Effect depends on the drug
D. None of the above

B

Allosteric activators bind on the same receptor but different site to improve the effect of another drug

7

Binding of acetylcholine its receptors triggers this cellular event:

A. The opening of sodium channels
B. Chloride ion enters cell
C. Hyperpolarization of the membrane
D. G-protein is activated

A

From SIM on the Mechanism of Drug Action and Signalling Mechanisms. Acetylcholine is the main NT at the NMJ which causes opening of Na channels leading to depolarization, and muscle contraction

8

What type of receptors does the mineralocoticod aldosterone bind to?

A. Ion channel
B. GPCR
C. Tyrosine kinase linked
D. Cytoplasmic/nuclear

D

GCs act on cytoplasmic/nuclear receptors. Another example is thyroid hormones

9

The following are proposed mechanisms for the development of tolerance and desensitization, except:

A. Endocytosis of receptors
B. Phosphorylation of G protein-coupled receptors
C. Changes in components of response distal to the receptor
D. Exocytosis of the receptor-vesicle complex

D

10

Tamoxifen is a partial agonist of estrogen. As a partial agonist, it will have the following properties:

A. Agonist in the breast, but anti-estrogenic in the bone and uterus
B. Agonist in the uterus and the bone, but anti-estrogenic in the breast
C. Agonist in the ovaries, but anti-estrogenic in the breast
D. B and C

B

Used to treat breast cancer, can prevent osteoporosis (more on raloxifene)

11

Avastatin marketed in 2011. Dr. de Dios wants to show its safety to her ovarian cancer patients. She did clinical study to 50 Filipino patients to collect adverse reactions to Avastatin. What phase is this?

A. Phase I
B. Phase 2
C. Phase 3
D. Phase 4

D

Phase 4 is POST-marketing phase

12

Using the relationship between volume of distribution, clearance, elimination rate constant, and half life, find out what happens to the half life of a drug if clearance is decreased by 50%

A. Half life will be increased by 50%
B. Half life will be increased by 100%
C. Half life will be decreased by 50%
D. Half life will be decreased by 100%

B

Ke = Cl/Vd
Ke = ln 2/ t0.5
ln 2/ t0.5 = Cl/Vd
t0.5 = Ln 2 X Vd/Cl
if Cl’ = 0.5 Cl
t0.5’ = ln 2 X Vd / 0.5 Cl
t0.5’ = 2 t0.5

13

Using the relationship between volume of distribution, clearance, elimination rate constant, and half life, find out what happens to the half life of a drug if the volume of distribution increase by 50% and clearance are simultaneously decreased by 50%

A. Half life will be increased by 50%
B. Half life will be decreased by 50%
C. No change

C

14

Using the relationship between volume of distribution, clearance, elimination rate constant, and half life, find out what happens to the half life of a drug if the volume of distribution and clearance are simultaneously decreased by 50% no change

A. Half life will be increased by 50%
B. Half life will be decreased by 50%
C. No change

C

Ke = Cl/Vd
Ke = ln 2/ t0.5
ln 2/ t0.5 = Cl/Vd
t0.5 = Ln 2 X Vd/Cl
if Cl’ = 0.5 Cl, and Vd’ = 0.5 Vd
t0.5’ = ln 2 X 0.5Vd / 0.5 Cl
t0.5’ = t0.5

15

In the first order compartment model, half life is equivalent to:

A. ln2/Vd
B. (ln2)(Vd)/CL
C. ln2(CL)/Vd

B

(Volume of distribution × ln2)/ Clearance
Ke = Cl/Vd
Ke = ln 2/ t0.5
ln 2/ t0.5 = Cl/Vd
t0.5 = Ln 2 X Vd/Cl

16

You want to give your patient 2.4 g of drug X per day. If the computed maximum dosing interval is 12.5 hours, which of the following is/are appropriate dosing regimens?

A. 1.2 grams every 12 hrs
B. 800 grams every 8 hours
C. 600 grams every 4 hours
D. A & B
E. All of the above

D

17

For drug X, 120 grams of IV bolus was given. The computed Area Under the Curve (AUC) is 100 AUC units. The oral dose of 150 mg drug X produces 75 AUC units. What is the absolute oral bioavailability?

A. 25%
B. 30%
C. 50%

C

BA = (AUC/dose)oral / (AUC/dose)IV
BA = (75/150)/(100/120)
BA = 60%

18

True or False: CYP 450 enzymes are called phase 2 metabolic enzymes

F

CYP 450 enzymes are called phase 1 metabolic enzymes.since they are oxidoreductases, Redox reactions are under phase I reactions

19

True or False: If drug X is metabolized into an inactive metabolite, and its inactive metabolite is excreted by the kidney, its mode of elimination is by metabolism and excretion.

F

Its mode of elimination is by metabolism only

20

True or False: In a one compartment model that followed first order input and first order elimination, elimination starts after mass excretion

F

21

True or False: If clearance of drug X is decreased by half, one needs to decrease its loading dose by 50%

F

Loading dose is dependent on Vd
DL = Cp X Vd
Maintenance dose is dpendent on Cl
DM = Cl X Cl X T

22

True or False: Receptors can create new function by binding.

F

23

Receptors which regulate biochemical and physiological functions are in themselves subject to regulatory homeostatic control, which come in the form of:

A. Upregulation
B. Downregulation or desensitization
C. Both

C

24

The semilogarithmic graded dose response curve has the following characteristics:

A. It is a sigmoid curve
B. It consists of 4 parameters: slope, potency, variability, maximal effect
C. The magnitude of the response decreases with greater concentration of the unbound drug at the receptor site
D. A & B only

D

The magnitude of the response INCREASES with greater concentration of the unbound drug at the receptor site

25

True or False: The protein binding of a drug is subject to competition that would be critically important in drug interaction if the percentage binding is 80% or above

T

26

The apparent volume of distribution is:

A. Physiological
B. Relatively low for weakly acidic drugs
C. Relatively high for weakly basic drugs
D. Can range from 8-500L or even 35,000
E. All except A

E

27

Of all the hepatic cyclic proteins forming binds the more that it is responsible for the greatest number of drugs is:

A. CYP 3A
B. CYP 450
C. CYP 27A1
D. CYP 1B1

A
, specifically CYP 3A4, CYP 2D6 naman ang most affected by genetic polymorphisms

28

In order for 99% of a drug to be cleared , how many half lives must pass?

10

29

True or False. Absolute bioavailability is determined when there are no intravenous data regarding a drug is available.

F

30

True or False. Incomplete absorption and hepatic metabolism cause bioavailability of an oral drug to be less than 1.

T