Flashcards in Pharmacology Deck (15):
Which is quicker, intramuscular or subcutaneous?
When you give a drug subcutaneously, how does it reach the systemic circulation?
Diffusion into capillaries or lymphatic vessels
Advantages of subcutaneous administration?
• 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.
Disadvantages of subcutaneous administration?
• Injection volume limited (1-2ml)
• Possible inflammation or irritation at infusion site
• Possible leakage at site
• Possible allergic reaction
If your drug is lipophilic, potent and has a relatively brief half life, what is the best way to give it?
Advantages of transdermal drug delivery?
Steady rate of drug delivery, avoidance of first-pass metabolism, rapid termination of action (if t1⁄2 is short)
Good patient compliance
Disadvantages of transdermal drug delivery
Relatively few drugs suitable for TDD, allergies, cost
Drugs which you could give via transdermal patch?
– Applies a short high voltage pulse
– Disrupts cell membrane
– Can enhance permeability of the skin by 4-fold
Applies a few mA to a small area of skin via an electrode.
Potency varies with thickness of stratum corneum
State of the skin
Lower potency in children/certain body sites
Which is more potent, a steroid cream or ointment?
1% hydrocortisone acetate, 0.1% hydrocortisone butyrate, which one is more potent?
0.1% hydrocortisone butyrate is POTENT!!
(1% hydrocortisone acetate is only mild!!)