Pharmacology

Question 1

Calculation of Volume of Distribution

Answer 1

Total amount of drug in body/ (plasma concentration of drug x weight)

Question 2

Volume of distribution in pre-term versus full-term infants

Answer 2

Preterm infants have a higher volume of distribution compared to full-term infants

Question 3

Do highly protein-bound drugs have a large or small volume of distribution

Answer 3

Small

Question 4

Most important enzyme system for phase 1 reactions

Answer 4

Cytochrome P450

Question 5

What is the most common phase 2 reaction?

Answer 5

Glucuronidation
(Phase 2 is conjugation of a drug with an endogenous compound)

Question 6

Zero order kinetics

Answer 6

Excrete a constant amount of drug per unit time regardless of the concentration; half life dependent on dosage; fraction of drug that is eliminated is not constant

Question 7

Drugs that have zero order kinetics

Answer 7

Aspirin, chloramphenicol, ethanol, and diazepam

Question 8

First order kinetics

Answer 8

Excrete a certain percentage of drug per unit time so the rate of drug elimination is directly proportional to the serum drug concentration; half-life is independent of drug dosage; the fraction of drug that is eliminated is constant

Question 9

Loading dose calculation

Answer 9

(Volume of distribution x plasma concentration of drug) / (fraction of drug which is active x active of drug which is bioavailable)

Question 10

Do preterm infants have faster or slower clearance compared to term infants

Answer 10

Slower

Question 11

Calculation of clearance of drug

Answer 11

Elimination rate constant x volume of distribution

Or

(Dose/interval)/ average steady state concentration

Question 12

Elimination half life concentration

Answer 12

(0.693 x Vd)/ clearance of drug

Question 13

Drugs that increase bilirubin levels by binding albumin and displacing unconjugated bilirubin from albumin

Answer 13

Ceftriaxone, sulfonamides, indomethacin

Question 14

Drugs that decrease bilirubin by increasing P450 metabolism and increasing the conjugation of bilirubin

Answer 14

Phenobarbital, rifampin

Question 15

Drugs that induce cytochrome P450

Answer 15

Chronic alcohol use, phenytoin, phenobarbital, rifampin, griseofulvin, carbamazipime, dexamethasone

Question 16

Drugs that inhibit cytochrome p450

Answer 16

Chloramphenicol, amiodarone, cimetidine, ketoconazole (and other azoles like fluconazole), sulfonamides, isoniazid, quinidines, indimethacin, methadone, omeprazole, ranitidine, macrolides (except azothromycin)

Question 17

Which PPI has the least effect on the cytochrome P4 50 system

Answer 17

Pantoprazole