Applied Pharmacokinetics: Routes of Administration Flashcards

1
Q

Name 3 routes of drug administration.

A
  1. Oral
  2. Rectal
  3. Parenteral
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What’s the limiting factor of oral drug administration

A

Absorption feom GIT

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

In which clinic setting is oral meds not absorbed?

A
  1. Critically ill patients
  2. Postoperative ileus
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Name factors that enhance or impair GI drug absorb

A
  1. Acidic drugs are non-ionized and, therefore, well absorbed
  2. Absorption area stomach small vs intestine
  3. Enhanced gastric emptying increase absorption vs. delayed GI emptying
  4. Tablet formulation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What factor affected by tablet Formulation?

A

Bioavailability

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Name types of drug formulations.

A
  1. Powder form
  2. Solid formulation
  3. Micronization
  4. Enteric coated tablets
  5. Sustained-release formulation.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Describe effects of tablet formululation on bioavailability of the active content; Powder- filled gelatine formulation

A

Fastest and most reliable as the shell desolves rapidly within the stomach

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Describe effects of tablet formululation on bioavailability of the active content: Solid formulation

A

It has to disintegrate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Describe effects of tablet formululation on bioavailability of the active content: Microionization

A

Particle size is reduced. Therefore, the surface area of the drug is increased, which is exposed to the solvant

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Describe effects of tablet formululation on bioavailability of the active content : Enteric coated

A

• Coat canbe gum/wax/cellulose
• these dissolve in an alkaline environment, i.e., small intestine, therefore abortion is delayed for hours

Example aspirin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Describe effects of tablet formululation on bioavailability of the active content : sustained-release formulation

A

• Allows release over extended period
•The dosing frequency is reduced
• keeps plasma concentration relatively static
• Contraindicated in drugs with long half lives

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are the characteristics of rectal drug administration

A
  1. Absorption incomplete and unpredictable
  2. Plasma concentration 80-90% that of oral formulation
  3. Good blood supply but small surface area no Villi in rectum
  4. Lower rectum Bypasses portal system therefor Avoids presystemic elimination
  5. Upper rectum frains into portal system
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

3 Uses of rectal drug administration

A
  1. Pediatric
  2. Unconscious patient with no iv access
  3. Persistent vomiting
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Give examples of drugs given PR by anaesthetist.

A

Analgesics : PARACETAMOL, NSAIDS, tramadol.
Antipyretics: paracetamol
Antiemetics: cyclizine, procloperazine
Sedatives: ketamin, Diazepam (rarely)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Caution with rectal drug administration

A
  1. Informed consent
  2. Not use in shocked patients poor blood supply.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Name 8 parenteral route of drug administration

A
  1. Percutaneous
  2. Mucosal
  3. Subcut & IM
  4. IV
  5. Intra-arterial
  6. Neurexial
  7. Intraneural
  8. Intrapleural and intra-articular
17
Q

What are the 2 routes for percutaneous drug administration?

A
  1. Transdermal
  2. Mucosal
18
Q

Percutaneous

A

Skin thick with keratin
Little water and fat
Acts as barrier to both water soluble and fat soluble drugs.

19
Q

Transde

A

Absorption depends on
1. Surface area and
2. lipid solubility
Therefore ideal for small lupophilic molecules that need low absorption rate to achieve satisfactory plasma concentration.
3. Caution skin allergy and toxic systematic absorption

20
Q

Transdermal: iontophoresis

A

Substance carrying a charge delivered/ propelled through skin by low electric current

21
Q

Nasal mucosa characterist

A

Absorption occurs readily
Ideal for pediatric premed except for midaz
Ideal route for:
• Desmopressin SIADH
• Cocain vasocostrictive toxic dose 2-3 mg/kg

22
Q

Buccal mucosa

A

Highly Vascular ideal for fat soluble drugs
Venous drainage goes directly to systemic circulation bypassing 1st pass metabolism
Fentanyl lollipop

23
Q

Sublingual mucosa

A

Small surface area
Highly vascular
Absorption variable and affected by
•Time in the mouth
• how rapid drug dissolves
• salava flow
3. Route Avoids intestinal destruction and 1st pass metabolism

Examples, propranolol, nifedipine, nitroglycerin spray

24
Q

Pulmonary mucosa

A

Absorption via alveolar capillary with thin membranes
Avoids QST pass metabolism
Small inhaled particles suspended in air and not precipitate

Adrenaline no longer recommended in this route

25
Q

Subcut and IM

A

Diffusion gradient required
Determined by regional blood flow and solubility of drug in Interstitial fluid
Absorption accelerated by hyaluronic acid

26
Q

Iv

A

100% bioavailability
Offers
• immediate response
• Titration of effects
• ideal in shocked patients

27
Q

Intra-arterial

A

Not for anaesthesia most drugs cause vasospasm, ischemia and tissue necrosis.
Used for targeted chemo

28
Q

Neurexial

A

• Into Subarachnoid or epidural
• Volume of drug determines spread
• Concentration determines the intensity
• Level of injection determines spread

29
Q

Intraneural

A

Used in trigeminal neuralgia alcohol directly injected to the gasserian ganglion to destroy it

30
Q

Intrapleural and Intra-arterial

A

• No systematic absorption
• For local pain relief
• intrapleural local anesthetic greatly absorbed

31
Q

Novel drug delivery systems

A

Carbon nanotubules
Pockets of drugs and antigen mixture
Liposomal suspension of bupivacaine