Routes Of Drug Administration

Question 1

List different methods of drug administration (13)

Answer 1

1) oral (po)
2) sublingual
3) buccal

Parenteral routes:

4) intravenous (IV)
5) intramuscular
6) intrathecal
7) intraperitoneal
8) intra- articular

9) rectal (PR)
10) vaginal
11) topical
12) transdermal
13) inhalation

Question 2

What is the aim of drug administration? (3)

Answer 2

1) to diliver drug to site of action
2) drug effect determined by concentration of drug in molecules in plasma
3) concentration determined by rate of entry of drug to plasma and rate of exit from plasma

Question 3

What are the advantages and disadvantages of oral drug administration (4, 4)

Answer 3

Most common method 
Advantages: 
1) easy, non-invasive, safe 
2) portable 
3) cheap 
4) good absorption 

Disadvantages:

1) delayed onset of action
2) absorption affected by stomach contents, pH, transmit time
3) difficulty with swallowing
4) reduced bioavailability

Question 4

What are the advantages and disadvantages of sublingual drug administration (3, 3)

Answer 4

Absorption across mucous membrane under the tongue 
Advantages:
1) quick absorption and onset of action 
2) avoids "first pass effect"
3) can remove tablet if necessary 

Disadvantage:

1) Spray cannot be removed
2) unpleasant taste?
3) short duration of action

Question 4

What is the “first pass effect”

Answer 4

The first-pass effect is a phenomenon of drug metabolism whereby the concentration of a drug is greatly reduced before it reaches the systemic circulation.

Question 5

What are the advantages and disadvantages of buccal drug administration (4, 1)

Answer 5

Absorption across mucous membrane of cheek 
Advantages: 
1) quick absorption and inset of action 
2) avoids "first pass effect"
3) can remove tablet if necessary 
4) longer duration of action 

Disadvantages
1) unpleasant taste ?

Question 7

Outline the advantages and disadvantages of intravenous (IV) drug administration (4, 7)

Answer 7

Direct administration into the bloodstream via a vein 
Advantages:
1) immediate delivery of drug 
2) 100% bioavailability 
3) large volumes 
4) rapid dilution 

Disadvantages:

1) pain/discomfort
2) acute overdose possible
3) infection risk
4) patient more dependent
5) reduced mobility
6) can’t remove drug once it’s given
7) expensive

Question 8

Outline the advantages and disadvantages of subcutaneous (SC) drug administration (3, 4)

Answer 8

Injection under the skin 
Advantages:
1) easier access than IV
2) slow uniform absorption 
3) rate of absorption can be controlled 

Disadvantages:

1) painful
2) infection risk
3) slow absorption
4) limited volume

Question 9

Outline the advantages and disadvantages of intramuscular (IM) drug administration (1, 6)

Answer 9

Injection into a muscle
Advantages:
1) easier than IV

Disadvantages:

1) painful
2) infection risk
3) limited volume
4) slow, erratic absorption
5) avoid in children
6) avoid in coagulopathy

Question 10

Outline the advantages and disadvantages of intrathecal (IT) drug administration (3, 3)

Answer 10

Injection into the sub-arachnoid space of the meninges , usually by lumbar puncture 
Advantages: 
1) treat/prevent malignancy 
2) anaesthesia 
3) treat infection 

Disadvantages:

1) infection risk
2) high risk procedure
3) catastrophic result if wrong drug given

Question 11

Outline the advantages and disadvantages of intraperitoneal (IP) drug administration (1, 2)

Answer 11

Injection into the peritoneal cavity
Advantages:
1) local administration of antibiotics for Continuous Ambulatory Peritoneal Dialysis (CAPD) patients

Disadvantages:

1) infection risk
2) risk of damaging organs

Question 12

Outline the advantages and disadvantages of intra-articular (IA) drug administration (1, 3)

Answer 12

Injection into a joint
Advantages:
1) local action

Disadvantages:

1) painful
2) limited volume
3) may damage cartilage

Question 13

List the three ways of delivering a drug rectally (PR) (3)

Answer 13

1) suppository
2) enema
3) rectal tube

Question 14

Outline the advantages and disadvantages of rectal drug administration (4, 3)

Answer 14

Advantages:

1) useful if patient vomiting
2) during seizures
3) rapid absorption of some drugs
4) local or systemic action

Disadvantages

1) less favoured
2) erratic absorption of some drugs
3) dosage form may be eliminated before absorption is complete

Question 15

Outline the advantages and disadvantages of vaginal (PV) drug administration (1, 1)

Answer 15

Pressaries , vaginal creams

Advantages:
1) local administration

Disadvantage:
1) less favoured by some

Question 16

Outline the advantages and disadvantages of topical (top) drug administration (2, 2)

Answer 16

Advantages:

1) local effect
2) soothing

Disadvantages:

1) messy
2) difficult application

Question 17

List the different topical forms of drug administration (5)

Answer 17

1) skin creams/ointments
2) lotions
3) eye/nasal/ear drops
4) eye ointment
5) ear/nasal sprays

Question 18

Outline the advantages and disadvantages of transdermal drug administration (3, 2)

Answer 18

Transdermal is a route of administration wherein active ingredients are delivered across the skin for systemic distribution. Patches, gels

Advantages:

1) Non-invasive
2) continuous
3) long lasting

Disadvantages

1) slow onset
2) fixed dose

Question 19

List the ways drugs can be delivered by inhalation (3)

Answer 19

1) nebulisers
2) inhalers
3) gaseous anaesthetics

Question 20

Outline the advantages and disadvantages of using inhalation for drug administration (3, 2)

Answer 20

Advantages:

1) large surface area for absorption
2) rich blood supply
3) local or systemic action

Disadvantages:

1) membrane irritation
2) equipment