Lecture 2: Basic Principles of Pharmacology II

Question 1

What forms of drugs can easily diffuse?

Answer 1

Nonionized forms

Question 2

What forms of drugs do not diffuse?

Answer 2

Ionized forms

Question 3

What are the 2 types of routes of administration?

Answer 3

1. Enteral (Oral, Rectal, Sublingual)

2. Parenteral (Intravenous, Intraarterial, Intramuscular, Subcutaneous, Intrathecal, Topical, Inhalation)

Question 4

What are some of the advantages of oral administration?

Answer 4

Easy, safe, prolonged absorption causing prolonged effect

Question 5

What are some of the disadvantages of oral administration?

Answer 5

1. Absorption may be too slow
2. Absorption variable and unpredictable
3. Drugs can be completely metabolized on first pass through liver
4. Not available for comatose, vomiting patients.

Question 6

What are some advantages of rectal administration?

Answer 6

1. Useful for infants, comatose, vomiting pts
2. Useful for foul-smelling, distasteful drugs
3. Useful for drugs destroyed in upper gastrointestinal tract
4. Avoids immediate metabolism liver

Question 7

What are some of the disadvantages of rectal administration?

Answer 7

1. Nuisance - poor compliance
2. Absorption may be erratic, incomplete
3. Rectal irritation

Question 8

What are some of the advantages of sublingual administration?

Answer 8

1. By-basses liver when first absorbed

2. Rapid absorption

Question 9

What are some of the disadvantages of sublingual administration?

Answer 9

1. Must be soluble in saliva, have appropriate pKa rapid absorption
2. Tablets must be small

Question 10

Advantages of intravenous administration?

Answer 10

1. Rapid effect
2. Can watch response and titrate dose
3. For drugs given in large volumes of fluid and continuous monitoring

Question 11

What are some of the disadvantages of intravenous administration?

Answer 11

1. Cost
2. Danger of infection
3. Possible anaphylactic rxn
4. Danger of embolus formation due to air, drug precipitation, RBC agglutination
5. Danger of adverse cardiovascular effects if administration too rapid

Question 12

Advantages of intraarterial route?

Answer 12

1. Administration of radioopaque material for visualization of circulatory tree
2. High conc. of drug going to local when desirable

Question 13

Disadvantages of the intraarterial administration?

Answer 13

As for iv administration

Question 14

What are some of the advantages of intramuscular?

Answer 14

1. When oral route is not available
2. Absorption less variable than with oral route
3. Absorption more rapid with s.c. route
4. Possibility of slowing absorption to prolong effect

Question 15

Disadvantages of intramuscular route?

Answer 15

1. Possible local necrosis
2. Accidental i.v. injection possible
3. Should not be used after anticoagulant administration

Question 16

Advantages of subcutaneous route?

Answer 16

1. Absorption usually slower than after i.m., and effect more prolonged

Question 17

Disadvantages of subcutaneous route?

Answer 17

As for i.m. administration

Question 18

Advantages of intrathecal?

Answer 18

When local effect on CNS required other route unsatisfactory

Question 19

Disadvantages of intrathecal?

Answer 19

1. Skill

2. Danger of spinal cord injury

Question 20

Advantages of topical?

Answer 20

1. for local action on or under skin

2. non-invasive

Question 21

Disadvantages of topical route?

Answer 21

1. Difficulty of absorption through skin

2. Danger of excessive absorption through membranes and systemic toxicity

Question 22

Advantages of inhalation route?

Answer 22

1. Rapid absorption for systemic action
2. High conc. attainable for local effect
3. Self administration possible

Question 23

Disadvantages of inhalation route?

Answer 23

1. Possible excessive absorption and systemic toxicity
2. Poor regulation of dosage
3. Irritation of pulmonary

Question 24

Define bioavailability

Answer 24

Fraction of dose available for biologic action

Question 25

What are the characteristics of bioavailability?

Answer 25

1. Pertains to oral drug administration where variable absorption or "first pass" effects will decrease the amount of drug which reaches the circulation 2. Measured by comparing the AUC (area under the curve) for the oral dose form vs the intravenous dose form.

Question 26

(FA) True or false | Ionized species are trapped in urine and cleared quickly.

Answer 26

True

Question 27

(FA) True of false | Neutral forms can be reabsorbed

Answer 27

True

Question 28

(FA) What are some of the examples of weak acids drugs?

Answer 28

Phenobarbital, methotrexate, aspirin

Question 29

(FA) What are the characteristics of weak acid drugs?

Answer 29

1. They are trapped in basic environment | 2. Treat overdose with bicarbonate

Question 30

(FA) What are some of the examples of weak base drugs?

Answer 30

Amphetamines

Question 31

What are the characteristics of weak base drugs?

Answer 31

1. They are trapped in acidic environments. | 2. Treat overdose with ammonium chloride.

Question 32

Protein bound drug can't cross

Answer 32

the capillary membrane

Question 33

Weak electrolyte drugs can be either

Answer 33

nonionized form or ionized form / weak acids or base

Question 34

Nonionized form

Answer 34

diffuse

Question 35

ionized form

Answer 35

do not diffuse

Question 36

pKa will help

Answer 36

to figure out ionized/nonionized form

Question 37

Drug administration could be either

Answer 37

enteral or parenteral

Question 38

What are some of the considerations for routes of administraiton?

Answer 38

1. Planned use of medication 2. Clinical setting - acute vs. chronic 3. Rapidly of onset of desired action 4. Specific target organ that the drug is intended to reach

Question 39

Parenteral means

Answer 39

you bypass the GI tract

Question 40

Enteral means

Answer 40

you use part of the GI tract

Question 41

What is the most advantage of oral administration?

Answer 41

Prolonged and maintain steady conc.

Question 42

Disadvantages of oral route?

Answer 42

The drugs have to pass the liver and will destroyed.

Question 43

Liver metabolism of the drug is called

Answer 43

First pass metabolism (effect)

Question 44

Advantages of rectal?

Answer 44

useful for comatose, vomiting pt. via suppository

Question 45

Sublingual route advantages?

Answer 45

1. By-passes liver when first absorbed 2. Rapid absorption 3. Tablets or sprays

Question 46

What kind of drug shows a strong first pass effect?

Answer 46

Opioid agonists are bio transformed in the liver by CYP450 enzymes

Question 47

Advantages of IV route?

Answer 47

1. Rapid effect | 2. Can titrate dose

Question 48

Disadvantages of IV route?

Answer 48

1. Danger of adverse cardiovascular effects if administration is too rapid 2. Formation of embolus

Question 49

Advantages of intraarterial route?

Answer 49

administration of radio material or a specific location in the brain

Question 50

Advantages of IM (Deep muscle) route?

Answer 50

when oral is not available, to slow absorption to prolong effect

Question 51

Advantages of SC?

Answer 51

Look at the note

Question 52

Advantages of intrathecal

Answer 52

when local effect on CNS required and other route unsatisfactory, usually for analgesia

Question 53

Advantages of inhalation?

Answer 53

1. high conc attainable for local effect (lung--> albutalol) 2. Rapid absorption for systemic action 3. Very close to i.v. absorption for volatile gases such as anesthetics or toxic gases

Question 54

Inhalation absorption will be

Answer 54

just below IV on a graph (plasma levels of drug vs. time)

Question 55

Advantages of subcutaneous

Answer 55

absorption usually slower than i.m.