Pharmacology

Question 1

Non-polar molecules dissolve?

Answer 1

Freely across lipid membranes

Question 2

Ionized molecules dissolve?

Answer 2

Low lipid solubility, can only permeate membrane with transporter

Question 3

Ion trapping: acidic drugs concentrated in?

Basic drugs concentrated in?

Answer 3

Acidic –> in high pH

Basic –> in low pH

Question 4

Effect urinary acidification on excretion?

Answer 4

accelerates excretion weak bases + retards excretion weak acids

Question 5

Carbonic anhydrase inhibitor reduces plasma pH, effect?

Answer 5

weakly acidic drugs concentrated in CNS, cause plasma repels them –> neurotoxicity

Question 6

Carrier mediated transport: active or passive transport –> solute carrier transporter (SLC) & ATP-binding cassete transporter (ABC)

Answer 6

SLC = passive down gradient
ABC = active

Question 7

SLC: organic cation transporter (OCT) & organic anion transporter (OAT)

Answer 7

OCT –> uniporter, OCT1 = hepatocytes, OCT2 = proximal renal tubules, nephrotoxicity
OAT –> secretion urate, prostaglandins, antibiotics, antivirals, NSAIDs, antineoplastic drugs

Question 8

ABC: present where? Effect co-location SLC?

Answer 8

Present in: renal tubular brush border, bile canaculi, astrocyte foot processes, GI tract
Co-location SLC: drug pumped into cell by SLC, pumped out of cell by ABC

Question 9

Bioavailability definition?

Answer 9

the fraction of an orally administered dose that reaches systemic circulation as intact drug

Question 10

bioequivalance definition?

Answer 10

based on maximum concentration achieved + time between dosing and Cmax

Question 11

Phase 1 reaction?

Answer 11

Catabolic: introduce reactive group, point of attack for phase 2
Liver mostly involved: cytochrome P450 enzymes

Question 12

Phase 2 reaction?

Answer 12

Anabolic (synthetic): conjugation = attach substituent group
Mainly in liver, can be in lungs or kidneys
UDP-glucoronyl transferase catalyses reaction

Question 13

Induction definition?

Answer 13

drugs that increase activity of microsomal oxidase and conjugating systems when administered repeatedly

Question 14

Processes accounting for renal drug excretion?

Answer 14

Glomerular filtration
Active tubular secretion –> OAT = acidic drugs — OCT = organic bases
Passive reabsorption

Question 15

First-order kinetics ?

Answer 15

rate of elimination is directly proportional to drug concentration –> exponential decay

Question 16

Repeated dosing effect: better to give large less frequent doses or small more frequent doses?

Answer 16

Small and more frequent –> more close to continuous infusion situation, smaller swings

Question 17

Absorption rate and peak concentration effect?

Answer 17

Slower the absorption, peak concentration appears later and lower and less sharp

Question 18

Zero-order kinetics ?

Answer 18

drug is removed at constant rate that is independent of plasma concentration –> linear pattern
Zero-order kinetics = saturation kinetics

Question 19

Saturation kinetics consequences?

Answer 19

Carrier or enzyme saturates, so duration of action is more dependent on dosing