Pharmacology

Question 1

Which is quicker, intramuscular or subcutaneous?

Answer 1

Intramuscular

Question 2

When you give a drug subcutaneously, how does it reach the systemic circulation?

Answer 2

Diffusion into capillaries or lymphatic vessels

Question 3

Advantages of subcutaneous administration?

Answer 3

• Absorption is relatively slow (advantageous/disadvantageous) due to poor vascular supply
• Route of administration for many protein drugs (e.g. insulin)
• Suitable for administration of oil-based drugs (e.g. steroids)
• Can be used to introduce a depot of drug of drug under the skin that is very slowly released into the circulation [e.g. certain contraceptive steroids (medroxyprogesterone) and antipsychotic drugs (fluphenazine decanoate)]
• Relatively simple and painless
• Can be used when other routes of administration can no longer be tolerated.

Question 4

Disadvantages of subcutaneous administration?

Answer 4

Disadvantages
• Injection volume limited (1-2ml)
• Possible inflammation or irritation at infusion site  
• Possible leakage at site  
• Possible allergic reaction

Question 5

If your drug is lipophilic, potent and has a relatively brief half life, what is the best way to give it?

Answer 5

Transdermal patch

Question 6

Advantages of transdermal drug delivery?

Answer 6

Steady rate of drug delivery, avoidance of first-pass metabolism, rapid termination of action (if t1⁄2 is short)

Good patient compliance

Question 7

Disadvantages of transdermal drug delivery

Answer 7

Relatively few drugs suitable for TDD, allergies, cost

Question 8

Drugs which you could give via transdermal patch?

Answer 8

Nicotine
GTN
Fentanyl
Estradiol

Question 9

Electroporation

Answer 9

– Applies a short high voltage pulse
– Disrupts cell membrane
– Can enhance permeability of the skin by 4-fold

Question 10

Iontophoresis

Answer 10

Applies a few mA to a small area of skin via an electrode.

Question 11

Body site

Answer 11

Potency varies with thickness of stratum corneum

Question 12

State of the skin

Answer 12

Lower potency in children/certain body sites

Question 13

Which is more potent, a steroid cream or ointment?

Answer 13

Steroid ointment

Question 14

1% hydrocortisone acetate, 0.1% hydrocortisone butyrate, which one is more potent?

Answer 14

0.1% hydrocortisone butyrate is POTENT!!

1% hydrocortisone acetate is only mild!!

Question 15

Steroid hormones, lipophilic or lipophobic?

Answer 15

Lipophilic