Lecture 8.2: Drug Administration

Question 1

What is Pharmacology?

Answer 1

Science of drug action on biological systems

Question 2

What is Pharmacodynamics?

Answer 2

It is what the drug does to the body

Question 3

What is Pharmacokinetics?

Answer 3

It is what the body does to the drug

Question 4

4 questions to be asked when prescribing drugs

Answer 4

• Is drug getting into patient?: Pharmaceutical process
• Is drug getting to site of action?: Pharmacokinetic
  process
• Is drug producing desired effect?: Pharmacodynamic
  process
• Is this translated to a therapeutic effect?: Therapeutic
  process

Question 5

What is a Drug?

Answer 5

A substance that changes a biological system by
interacting with it

Question 6

What is a Medication?

Answer 6

A drug presented in a form intended for restoring or
preserving health

Question 7

The drug (tablet) is mixed with other substances (excipients) to allow…? (4)

Answer 7

• Manufacturability
• Practicality of administration
• Control onset of action
• Control duration of action

Question 8

What is a Disintegrant?

Answer 8

A substance that helps the tablet breakdown and dissolve in GI tract

Question 9

What is a Binder?

Answer 9

A substance holding the tablet together

Question 10

What is a Lubricant?

Answer 10

Substance that prevents “wear & tear” on tablet making equipment and facilitates removal from tablet moulds

Question 11

What is a Diluent?

Answer 11

“Filler” providing extra volume and weight

Question 12

What is the Process of making a Tablet? (6 Steps)

Answer 12

1) Active Ingredient + Excipients
2) Mixing and Granulation
3) Drying
4) Compression
5) Coating
6) Packaging

Question 13

Film Coated Tablets

Answer 13

Core – contains drug & excipients
Film – non functional

Question 14

Pros of Film Coated Tablets (6)

Answer 14

• Improve appearance
• Ease of swallowing
• Product stability – mechanical integrity
• Increased shelf life
• Taste masking
• Identification & trade marking

Question 15

What is an Active Ingredient?

Answer 15

Chemical substance intended to provide the desired pharmacological effect

Question 16

Modified Release Film Coatings

Answer 16

1) Delayed-Release (e.g. gastro-resistant/ enteric
coating)
2) Sustained / Extended-Release Coatings

Question 17

Why might drugs have Delayed-Release (e.g. gastro-resistant/ enteric coating)?

Answer 17

• To protect the acid-labile drug substances from the
  acidic pH of gastric acid
• To prevent gastric ulceration due to irritation by
  certain drugs such as aspirin nonsteroidal anti-
  inflammatory compounds

Question 18

Benefits of Sustained / Extended-Release Coatings (5)

Answer 18

• Reduced local adverse effects in the gastrointestinal
  tract
• Reduced adverse effects associated with peak blood
  levels
• Less fluctuation in blood levels across the course of
  the day
• Artificially extended half-life
• Convenience of dosing - improved compliance

Question 19

What are some common sites of Intramuscular Injection? (4)

Answer 19

• Deltoid
• Gluteal
• Vastus lateralis
• Rectus femoris

Question 20

What is a disadvantage of subcutaneous injection?

Answer 20

Absorption slower than via the intramuscular route

Question 21

What drugs are subcutaneous injections better for?

Answer 21

Beneficial continuous absorption of a drug is required:
* Insulin
* Heparin

Question 22

Name Types of Injections (6)

Answer 22

• Intravenous
• Intramuscular
• Subcutaneous
• Intraarticular
• Intraosseous
• Intrathecal
• Intravitreal

Question 23

What is an Intrathecal Injection?

Answer 23

Direct injection of the drug into the CSF (cerebro-spinal fluid), circumvents blood brain barrier

Question 24

What is an Intravitreal Injection?

Answer 24

In which the substance is delivered into the vitreous humor of the eye

Question 25

What are Emollients?

Answer 25

Moisturising treatments applied directly to the skin to soothe and hydrate it

Question 26

What is a topical steroid?

Answer 26

• Topical steroids are the topical forms of corticosteroids
  Topical steroids are the most commonly prescribed topical medications for the treatment of rash, eczema, and dermatitis
  Topical steroids have anti-inflammatory properties and are classified based on their skin vasoconstrictive abilities

Question 27

Side-Effects of Topical Steroids (5)

Answer 27

• Skin thinning (atrophy) of time
• Stretch marks (striae)
• Easy bruising (purpura) and tearing of the skin
• Enlarged blood vessels (telangiectasia)
• Localised increased hair thickness and length (hypertrichosis)

Question 28

How are Transdermal Medications administered?

Answer 28

“Patch” containing the drug is applied to the skin, it seeps out of the patch through the skin (at a predetermined rate) into the capillary bed

Question 29

Advantages of administering drugs transdermally (4)

Answer 29

• Constant plasma concentrations of a drug
• Non-invasive
• Self-administered
• Simple (patient adherence)

Question 30

Disadvantages of administering drugs transdermally ()

Answer 30

• Rashes/Irritation due to patch
• Drug absorption limited by skin permeability
• Cannot reach high concentrations in blood
• Ionic drugs cannot be administered via this route
• Lipophilic & Hydrophilic drugs need modifying

Question 31

Why is the nasal route good for drug administration?

Answer 31

Nasal mucosa is very vascular and easily accessible, non-keratinised epithelium (high permeability)

Question 32

What types of drugs is the nasal route good for?

Answer 32

Feasible for peptides: AHD, gonadotropin releasing hormone

Question 33

What is the Therapeutic Ratio?

Answer 33

Maximum tolerated dose/Minimum effective dose
LD50/ED50