Flashcards in 9.7 Pharmacology 4 Deck (38)
routes of administration: categories
- enteral (alimentary canal)
- parenteral (nonalimentary)
a significant amount of the drug is metabolized and destroyed prior to reaching the site of action
Drug is transported to the liver via
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?
under the tongue
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?
methods of parenteral administration
drawbacks to inhalation drugs
- may irritate alveoli or nasal passages
- can get trapped by cilia and mucus
What types of drugs are often inhaled?
- specific pulmonary treatments
- nonlipid-soluble agents
example of larger nonlipid-soluble agents that are inhaled
- small proteins (insulin)
Drugs can be introduced systemically or locally via
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
- radiopaque dyes for dx procedures
subcutaneous drug delivery for
- local procedures (lidocaine, insulin)
- hormonal implants (slow release, ex. birth control)
What adverse effect may subcutaneous drug delivery cause?
local tissue irritation
intramuscular administration used for
- local tx (Botox)
- relatively steady, prolonged release into systemic circulation
effect of intramuscular administration (speed)
- relatively rapid effect
- doesn't cause the sudden increase in plasma levels
What is intrathecal administration?
meds released in a sheath, such as spinal subarachnoid space
What might be used to bypass the BBB and reach the CNS?
- narcotic analgesics & anesthetics
- can be delivered adjacent to SC
**antibiotics, anti-cancer drugs
topical medications absorbed through
- mucous membranes
What are topical meds usually used for?
- absorption through systemic circulation is relatively small
transdermal meds must be able to
- penetrate the skin
- not be degraded by drug-metabolizing enzymes in the skin
What are transdermal meds usually mixed with?
oily or other soluble base
usually in patch form
Benefit to transdermal meds
slow, controlled release at a relatively constant level for prolonged periods of time
ionto and phonophoresis delivers meds to
- subcutaneous muscle
common transdermal meds
- hormonal agents