9.7 Pharmacology 4 Flashcards
routes of administration: categories
- enteral (alimentary canal)
- parenteral (nonalimentary)
first-pass effect
a significant amount of the drug is metabolized and destroyed prior to reaching the site of action
Drug is transported to the liver via
portal vein
Dosage of an oral drug and first-pass effect
must be strong enough to survive hepatic degradation
Reasons why some drugs can’t be given orally
- first-pass effect
- unpredictable rate of absorption into the bloodstream
What are the modes of enteral administration?
- sublingual
- buccal
- rectal
sublingual
under the tongue
buccal
between cheek and gum
How do sublingual and buccal drugs enter the bloodstream?
- mouth venous drainage system
- goes to superior vena cava and heart
NO FIRST PASS
What are sublingual and buccal drugs good for?
- fast-acting drugs like nitroglycerine
- must be able to be absorbed through oral mucosa and into venous drainage
benefit to rectal administration
used when oral isn’t possible, such as with anti-vomiting or hemmorhoids
drawback to rectal administration
many are absorbed poorly through rectal mucosa
Which drugs are not usually subject to first-pass effect?
parenteral
methods of parenteral administration
- inhalation
- injection
- IV
- intra-arterial
- subcutaneous
- intramuscular
- intrathecal
- topical
- transdermal
drawbacks to inhalation drugs
- may irritate alveoli or nasal passages
- can get trapped by cilia and mucus
What types of drugs are often inhaled?
- anesthetics
- specific pulmonary treatments
- nonlipid-soluble agents
- DNA
example of larger nonlipid-soluble agents that are inhaled
- peptides
- small proteins (insulin)
Drugs can be introduced systemically or locally via
injection
benefit of an IV bolus
- accurate, known quantity of drug over short period
- peak level occurs almost instantly
IV infusion delivered via
indwelling IV cannula
IV infusion allow for
prolonged, steady infusion
IV infusions prevent
large plasma fluctuation of a bolus
function of intra-arterial drug delivery
puts large amts of drug into specific target site
intra-arterial deliver is usually reserved for
- chemotherapy
- radiopaque dyes for dx procedures
