Module 2 - Part 2 Flashcards
When is the rectal route most useful?
when the patient is unconscious or vomitting
Describe rectal administration and its impact on first pass metabolism.
Approximately 50% of rectally administered drugs bypass the liver
What are some disadvantages of rectal administration?
Incomplete absorption and some drugs may irritate the rectal mucosa
What are the most common peripheral veins used for IV injection?
veins on the back of the hand or the median cubital vein
Single dose administered over a short duration.
IV bolus
A drug is administered under continuous infusion over a prolonged period
IV drip
Drugs that are given by IV drip are usually placed in a vehicle. What does this mean?
Drugs are diluted in a vehicle - i.e. saline in an IV bag
What are advantages of IV injection?
no barriers to absorption - 100% bioavailability
Precise control of drug dosage and duration of action
Allows administration of poorly soluble drugs that must be diluted in a large volume
Allows the injection of irritant drugs - can be injected slowly and diluted in the blood
What are disadvantages of IV administration?
expensive, invasive and inconvenient (need HCP)
Drugs cannot be removed once injected
Risk of infection and fluid overload
Risk of injecting incorrect formulation
What is the only barrier to absorption in SC injection?
capillary wall
What characteristic is necessary for a drug to be given by SC injection?
drug must be water soluble to dissolve in ECF
What drug types should not use the SC route?
Irritant drugs - cause severe pain and/or tissue swelling
What are the primary determinants of the rate of absorption of SQ drugs?
Blood flow and water solubility
What are the primary determinants of the rate of IM drug absorption?
Water solubility and (local) blood flow
Absorption of IM drugs is determined by what?
Ability to pass through fenestrations
