Kinestic,dynamics and calculations

Question 1

how to calculate loading dose of a drug

Answer 1

desired plasma concentration xx volume of distrubution / bioavailability

Question 2

how to calculate maintenance dose

Answer 2

(desired plasma concentration x Cr clearance x dosage interval) / bioavailability

Question 3

changes in maintenance dose and loading dose in liver/renal disease

Answer 3

maintenance dose decreases but loading dose in unchanged

Question 4

what type of inhibitors decrease potency and efficacy

Answer 4

irreversible competitive and non-competitive inhibitors decrease efficacy

reversible inhibitors decrease potency

Question 5

biochemical reactions involved in phase I of drug metabolism (lipophylic)

Answer 5

reduction, oxidation, hydrolysis

Question 6

biochemical reactions involved in phase II drug metabolism (hydrophilic)

Answer 6

methylation, glucoronidation, acetylation, sulfation

Question 7

drugs which can cause sulpha allergy

Answer 7

Scary Sulpha Pharm FACTS
Sulphonamide abx
sulphonylureas
probenacid
furosemide
acetazolamide
celecoxib
thiazides
sulfalsalazine

Question 8

effects of sulpha allergy

Answer 8

SJS
UTI’s
haemolytic anaemia, thrombocytopenia, agranuloctosis
pruritus, hives
interstitial nephritis

Question 9

what enzyme is responsible for the formation of acetylcholine

Answer 9

choline acetyltransferase

Question 10

how to measure creatinine clearance

Answer 10

Cr Cl = rate of elimination of drug / plasma conc drug

or

CrCl = vol distrubution Vd x elimination contant Ke

Question 11

what 2 variables define the safety of a drug and calculation of therapeutic index

Answer 11

median toxic dose / median effective dose

Question 12

what is pKa

Answer 12

PH at which a drug is 50% ionized and 50% non-ionized represents how the strenth of a weak acid or base

Question 13

first order elimination

Answer 13

rate of elimination is directly proportional to concentration of drug

Question 14

zero order elimination

Answer 14

constant rate of elimination of drug regardless of concentration

Question 15

examples of drugs that exibit zero order elimination

Answer 15

phenytoin
ethanol
aspirin
(PEA is shaped like a O as in the o in zerO)

Question 16

what is the term to describe a decrease in drug efficiency after repeated use

Answer 16

tachyphylactic

Question 17

what is the term to describe when two drugs are taken together and their effects are equal to their individual effects put together

Answer 17

adidtive

Question 18

what is the term to describe when a drug is added for the full effects of drug B

Answer 18

permissive

Question 19

does liver/kidney disease increase or decrease volume of distrubution

Answer 19

increases volume of distrubution to decreased protein binding

Question 20

large, charged molecules that are protein bound are found in what compartment? do they have low, med or high vol of distrubution?

Answer 20

intravascular fluid
low vol distrubution

Question 21

what compartment are small hydrophillic molecules are found and do they have low, med or high vol of distrubution?

Answer 21

ECF
medium

Question 22

what compartment are small lipophyllic molecules found and do they have small, med or high vol of distrubution?

Answer 22

found in all tissues incl fat
high vol distrubution

Question 23

location of alpha 1 receptors and function

Answer 23

smooth muscle - vasoconstriction

Question 24

location of alpha 2 receptors and function

Answer 24

pre-synaptic nerves - regulates release of neurotransmitters

Question 25

location of beta 1 receptors and function

Answer 25

heart - positive inotropy and chronotropy

Question 26

location of beta 2 receptors and function

Answer 26

smooth muscle - vasodilatation

Question 27

location of beta 3 receptors and function

Answer 27

fat tissue - lipolysis and thermogenesis

Question 28

M1, M2 and M3 receptors function

Answer 28

M1 - Brain and gut. Mediates higher cognitive function and stimulates enteric nervous system M2 - Heart. Decreases HR and contractility of atria M3 - increases exocrine gland secretion, gut peristalsis, bladder contraction, bronchoconstriction, vasodilatation, miosis, accomadation

Question 29

location of D1 and D2 receptors and function

Answer 29

D1 relaxes renal vascular smooth muscle, activates direct pathway of striatum D2 modulates transmitter release, inhibits indirect pathway of striatum

Question 30

location of H1 and H2 receptors and function

Answer 30

H1 - bronchoconsriction, airway mucous production, increases vascular permeability/vasodilation, pruritus H2 - increased gastric acid secretion

Question 31

location of V1 and V2 receptors and function

Answer 31

V1 - vascular smooth muscle contraction V2 - increases water permeability and reabsoption via upregulating aquaporin 2 in collecting tubules of kidney. increases release vWF.

Question 32

term to describe when drug A (which has no therapeutic action) is used to enhance the effects of drug B

Answer 32

potentiation

Question 33

do competitive antagonists decrease potency or efficiacy

Answer 33

decrease potency

Question 34

do non-competitive antagonists decrease potency or efficacy

Answer 34

decrease efficacy

Question 35

what type of drugs increase the michaelis-mentin constant (Km)

Answer 35

competitive inhibitors

Question 36

what enzyme is activated when Gq receptors are activated

Answer 36

phsopholipase C

Question 37

what effects does activation of phospholipase cause

Answer 37

increased vascular smooth muscle contraction + permeability increased bronchial constriction + secretions + pruritus stimulates enteric nervous system activates higher cognitive functions miosis + acccomodation

Question 38

what enzyme is activated when Gi and Gs receptors are acted upon and their effects

Answer 38

adenylyl cyclase --> protein kinase A Gi inhibits, Gs stimulates

Question 39

in first order kinetics, how many half lives does it take for a drug that infused at a constant rate to reach steady state

Answer 39

4-5 half lives

Question 40

in first order kinetics, how many half lives does it take for a drug that is infused at a constant rate to reach 90% of its steady state

Answer 40

3.3 half lives

Question 41

in first order kinetics, what is steady state

Answer 41

its an equillibrium in which the drug concentration stays constant (i.e. rate of excretion is = rate of administration)