Lecture 2: Basic Principles of Pharmacology II Flashcards

1
Q

What forms of drugs can easily diffuse?

A

Nonionized forms

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2
Q

What forms of drugs do not diffuse?

A

Ionized forms

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3
Q

What are the 2 types of routes of administration?

A
  1. Enteral (Oral, Rectal, Sublingual)

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

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4
Q

What are some of the advantages of oral administration?

A

Easy, safe, prolonged absorption causing prolonged effect

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5
Q

What are some of the disadvantages of oral administration?

A
  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.
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6
Q

What are some advantages of rectal administration?

A
  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
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7
Q

What are some of the disadvantages of rectal administration?

A
  1. Nuisance - poor compliance
  2. Absorption may be erratic, incomplete
  3. Rectal irritation
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8
Q

What are some of the advantages of sublingual administration?

A
  1. By-basses liver when first absorbed

2. Rapid absorption

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9
Q

What are some of the disadvantages of sublingual administration?

A
  1. Must be soluble in saliva, have appropriate pKa rapid absorption
  2. Tablets must be small
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10
Q

Advantages of intravenous administration?

A
  1. Rapid effect
  2. Can watch response and titrate dose
  3. For drugs given in large volumes of fluid and continuous monitoring
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11
Q

What are some of the disadvantages of intravenous administration?

A
  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
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12
Q

Advantages of intraarterial route?

A
  1. Administration of radioopaque material for visualization of circulatory tree
  2. High conc. of drug going to local when desirable
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13
Q

Disadvantages of the intraarterial administration?

A

As for iv administration

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14
Q

What are some of the advantages of intramuscular?

A
  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
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15
Q

Disadvantages of intramuscular route?

A
  1. Possible local necrosis
  2. Accidental i.v. injection possible
  3. Should not be used after anticoagulant administration
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16
Q

Advantages of subcutaneous route?

A
  1. Absorption usually slower than after i.m., and effect more prolonged
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17
Q

Disadvantages of subcutaneous route?

A

As for i.m. administration

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18
Q

Advantages of intrathecal?

A

When local effect on CNS required other route unsatisfactory

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19
Q

Disadvantages of intrathecal?

A
  1. Skill

2. Danger of spinal cord injury

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20
Q

Advantages of topical?

A
  1. for local action on or under skin

2. non-invasive

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21
Q

Disadvantages of topical route?

A
  1. Difficulty of absorption through skin

2. Danger of excessive absorption through membranes and systemic toxicity

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22
Q

Advantages of inhalation route?

A
  1. Rapid absorption for systemic action
  2. High conc. attainable for local effect
  3. Self administration possible
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23
Q

Disadvantages of inhalation route?

A
  1. Possible excessive absorption and systemic toxicity
  2. Poor regulation of dosage
  3. Irritation of pulmonary
24
Q

Define bioavailability

A

Fraction of dose available for biologic action

25
Q

What are the characteristics of bioavailability?

A
  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.
26
Q

(FA) True or false

Ionized species are trapped in urine and cleared quickly.

A

True

27
Q

(FA) True of false

Neutral forms can be reabsorbed

A

True

28
Q

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

A

Phenobarbital, methotrexate, aspirin

29
Q

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

A
  1. They are trapped in basic environment

2. Treat overdose with bicarbonate

30
Q

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

A

Amphetamines

31
Q

What are the characteristics of weak base drugs?

A
  1. They are trapped in acidic environments.

2. Treat overdose with ammonium chloride.

32
Q

Protein bound drug can’t cross

A

the capillary membrane

33
Q

Weak electrolyte drugs can be either

A

nonionized form or ionized form / weak acids or base

34
Q

Nonionized form

A

diffuse

35
Q

ionized form

A

do not diffuse

36
Q

pKa will help

A

to figure out ionized/nonionized form

37
Q

Drug administration could be either

A

enteral or parenteral

38
Q

What are some of the considerations for routes of administraiton?

A
  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
39
Q

Parenteral means

A

you bypass the GI tract

40
Q

Enteral means

A

you use part of the GI tract

41
Q

What is the most advantage of oral administration?

A

Prolonged and maintain steady conc.

42
Q

Disadvantages of oral route?

A

The drugs have to pass the liver and will destroyed.

43
Q

Liver metabolism of the drug is called

A

First pass metabolism (effect)

44
Q

Advantages of rectal?

A

useful for comatose, vomiting pt. via suppository

45
Q

Sublingual route advantages?

A
  1. By-passes liver when first absorbed
  2. Rapid absorption
  3. Tablets or sprays
46
Q

What kind of drug shows a strong first pass effect?

A

Opioid agonists are bio transformed in the liver by CYP450 enzymes

47
Q

Advantages of IV route?

A
  1. Rapid effect

2. Can titrate dose

48
Q

Disadvantages of IV route?

A
  1. Danger of adverse cardiovascular effects if administration is too rapid
  2. Formation of embolus
49
Q

Advantages of intraarterial route?

A

administration of radio material or a specific location in the brain

50
Q

Advantages of IM (Deep muscle) route?

A

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

51
Q

Advantages of SC?

A

Look at the note

52
Q

Advantages of intrathecal

A

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

53
Q

Advantages of inhalation?

A
  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
54
Q

Inhalation absorption will be

A

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

55
Q

Advantages of subcutaneous

A

absorption usually slower than i.m.