Introduction to Pharmacology, Drug Discovery, Routes of Administration

Question 1

Define generic, brand and chemical name of the drugs

Answer 1

Generic: Derived from the chemical name and non proprietary
Brand: Assigned to the compound by the pharmaceutical company
Chemical: refers to the specific compounds structure

Question 2

What are Schedule I drugs?

Answer 2

Schedule I: Drugs or chemicals with no currently accepted medical use with the high potential for abuse
Heroin, LSD, Weed, MDMA

Question 3

What are Schedule II drugs?

Answer 3

Schedule II: drugs or chemicals with a high potential for abuse with accepted medical use, can lead to severe psychological or physical dependence
Methylphenidate, methamphetamine, oxycodone, morphine, methadone, hydromorphone, fentanyl, cocaine

Question 4

What are schedule III drugs?

Answer 4

Schedule III: Moderate or lower abuse potential compared to schedule II
Anabolic steroids, testosterone, codeine, ketamine

Question 5

What are Schedule IV drugs?

Answer 5

Schedule IV: Lowest potential for abuse and lower risk of dependence
Diazepam, Lorazepam, Phenobarbital, Propoxyphene, tramadol

Question 6

What are Schedule V drugs?

Answer 6

Schedule V: Lowest abuse potential
Low dose opioids in cough meds, lamotil, pregabalin

Question 7

What is Pharmacology?

Answer 7

Pharmacology is a broad umbrella term that encompasses pharmacotherapeutics and toxicology.
Pharmacotherapeutics can be further divided into pharmacokinetics and pharmacodynamics.

Question 8

What is pharmacokinetics?

Answer 8

What the body does to the drug (ADME)
Absorption
Distribution
Metabolism
Excretion

Question 9

What is Pharmacodynamics?

Answer 9

what the drug does to the body
MOA
Dose Response
Effects
SE
ADRs

Question 10

what is pharmacodynamics dependent on?

Answer 10

Depends upon drug receptors and the ability of the drugs to bind to those receptors

Question 11

what factors affect absorption?

Answer 11

Bioavailability is affected by stomach acidity, gastric emptying, surface area, GI enzymes, and developmental changes

Question 12

what is bioavailability? What factors affect it?

Answer 12

The extent to which a drug reaches systemic circulation
Routes of administration
Ability to cross the membrane

Question 13

What is toxicology?

Answer 13

the branch of science concerned with the nature, effects, and detection of poisons.

Question 14

what factors affect drug distribution?

Answer 14

tissue permeability, blood flow, binding to plasma protein, binding to sub cellular components

Question 15

Describe Phase-I and Phase-II drug metabolism

Answer 15

Phase I: convert a parent drug to a polar active metabolite through unmasking or insertion of a polar functional group (CYP450)
Phase II: convert the parent drug to a polar inactive metabolite via conjugation of subgroups (sulphates, glycine, acetylation, methylation)

Question 16

With regard to drug metabolism, what are CYP inductors and CYP inhibitors?

Answer 16

Induction: Rifampin, Carbamazepine
Inhibition: Valproic acid, Fluoxetine

Question 17

Describe absorption of drugs in Infants

Answer 17

• less stomach acid which increases bioavailability
• delayed gastric emptying which increases the time to reach therapeutic concentration
  -larger relative skin surface area which increases cutaneous perfusion
• thinner stratum corneum increases absorption of topicals

Question 18

Describe absorption, distribution, and excretion of drugs in the elderly

Answer 18

A: increased gastric PH and delayed gastric emptying increases the time to reach therapeutic concentrations
D: decreased TBW to 53% and increased body fat and decreased serum albumin binding
E: decreased glomerular filtration and tubular secretion (main reason for adverse reactions!)

Question 19

What is half life?

Answer 19

The amount of time required for 50% of the drug remaining the in the body to eliminated

Question 20

Active vs Passive Transport

Answer 20

Active: Minerals, sugars, and amino acids move against a concentration gradient with an input of energy
Passive: Water and water soluble substances (urea and glycerol) and small lipids move with a concentration gradient

Question 21

What are the major organs of drug metabolism and excretions?

Answer 21

The liver is the major organ that metabolizes drugs
The kidney is the major site of drug elimination and drugs are excreted in the urine

Question 22

What is Dose Response?

Answer 22

Provides information about the dosage range over which the drug is effective, provides information on peak response

Question 23

What is potency?

Answer 23

the dose that produces a given response in a specific amplitude

Question 24

What is median effective dose?

Answer 24

E50
Dose at which 50% of the population responds to the drug in a specific manner

Question 25

What is median toxic dose?

Answer 25

T50
Dose at which 50% of the group exhibits the adverse effects

Question 26

what is median lethal dose

Answer 26

L50
The dose that causes death in 50% of the group

Question 27

what is therapeutic index?

Answer 27

The therapeutic index is the indicator of the drugs safety. The greater the TI, the safer the drug. A greater TI indicates that it takes a large dose to have a toxic response.
TI=TD50/ED50
(median toxic dose/ median effective dose)

Question 28

what is efficacy of a drug?

Answer 28

The efficacy of a drug is its ability to produce the maximal response possible for a particular biological system and relates to the extent of functional change that can be imparted to the receptor by the drug, based on its affinity for the receptor

Question 29

What is drug affinity?

Answer 29

It tells us how attracted a drug is to its receptors.

Question 30

Define Agonist, Partial Agonist, Mixed agonist/antagonist, Antagonist

Answer 30

Agonist: Drugs that occupy receptors and activate them
Partial agonist: does not evoke a maximal response or fully activate a receptor
Antagonist: Drugs that occupy receptors but do NOT activate them. They block receptor activation by agonists.
Mixed antagonist and agonist: Simultaneously stimulate receptor subtypes while blocking other receptor subtypes

Question 31

Compare and contrast competitive and non-competitive antagonist

Answer 31

A competitive antagonist binds to the same site as the agonist but does not activate it, thus blocks the agonist’s action.
A non-competitive antagonist binds to an allosteric (non-agonist) site on the receptor to prevent activation of the receptor.

Question 32

Drug development and Approval: Preclinical Testing

Answer 32

1-3 years
animal trials provide preliminary info on PK and PD properties of the compound

Question 33

Drug development and Approval: Human Clinical Testing

Answer 33

6-8 years
Phase I: is it safe? Pk?
Phase II: Does it work in patients?
Phase III: Does it work double blind?

Question 34

Drug development and Approval: Phase IV

Answer 34

Post marketing surveillance is on going

Question 35

What are the various routes of administration?
Which are subject to first pass?

Answer 35

Enteral: oral, sublingual, rectal, buccal (ORAL SUBJECT TO FIRST PASS)
Parental: inhalation, injection, topical, transdermal

Question 36

what is first pass effect?

Answer 36

Oral drugs are subject to the first pass effect. It is a phenomenon of drug metabolism whereby the concentration of a drug is greatly reduced before it reaches the systemic circulation.
mucous membrane of the stomach–> portal vein –> liver and metabolized