parenteral drug administration Flashcards
what does ‘parenteral route’ mean?
drug is administered by a route OTHER than the gastro-intestinal tract
Enteral known as
gut
what does ‘intrathecal route’ mean?
into the CNS (into cerebral spinal fluid)
what is an intravenous injection?
injection of a medication or another substance into a vein and directly into the bloodstream
2 example of IV injection
antibiotics, analgesics
what is an intramuscular injection? IM
technique used to deliver a medication deep into the muscles
Examples of IM injections?
Hepatitis A and B vaccines, BCG vaccine
Skin anatomy layers: order from top to bottom (4)
epidermis, dermis, subcutaneous tissue, muscle
IM injection given at ?
90 degrees to the skin
Subcutaneous injection
injection given into the subcutaneous fat under the skin
2 examples of subcutaneous injection
insulin, heparin
what is an intradermal injection?
injection administered into the dermis (just below the epidermis)
2 examples of intradermal injection?
lidocaine (local anaesthetic), allergy testing
Advantages of IV
very fast
predictable absorption
Can give drug as infusion = achieve steady state with narrow therapeutic window
disdvantages of IV
high conc. peak so high risk of side effects
challenging to insert line/ canula
Advantages of subcutaneous
predictable absorption
fast onset
disadvantages of subcutaneous
small volumes only as there is a limited space in the subcutaneous tissue
pain / injection site reactions
absorption reduced in shock
Advantages of intramuscular
fast onset
disadvantages of intramuscular
small volume only
painful
absorption reduced in shock
Advantages of intradermal
evokes an antigen response
Disadvantage of intradermal
small volumes only
no significant absorption
Disadvantage of intradermal
small volumes only
no significant absorption
transdermal administration
through the skin
why can transdermal application be both parenteral and topical?
bypasses GI system and can be applied to body surface
why must drug be lipid soluble is administered transdermally?
epidermis is resistant to water
example of transdermal administration
nicotine and pain patches
Advantages of transdermal administration
convenient and acceptable
disadvantages of transdermal administration
can cause local skin reactions
case: 24 year old experiencing anaphylaxis reaction to nuts. What drug and route of administration? explain
Adrenaline, IM injection because rapid and no time to insert canular
case: 65 year old in ER with pneumonia, high temperature and low blood pressure. What drug and route of administration? explain
antibiotics, IV injection because quick and available (shes in the ER)
case: 22 year old man with type 1 diabetes. What drug and route of administration? explain
insulin, subcutaneous injection because precise absorption and sustained release
Drug factors influencing absorption
lipid and water solubility
molecular size and charge
concentration
drug formulation
patient factors influencing absorption
Area/ volume of absorption
pH
health status
other substances
vascularity
What is vascularity?
blood flow to an area
bolus define:
single large dose of a drug given over a short period of time
