Chapter 3 And 4 Flashcards
First pass
(Inactivation) in liver metabolized and destroyed
Drug is transported directly into the liver via the portal vein
Sublingual and buccal
Faster effects than swallowing the drug (for acute angina)
Rectal
Good for patient who is unconscious or when vomiting prevents drugs from being taken orally
Absorbed poorly or incompletely and irritation of the rectal mucosa
Paraenteral inhilation
Rapid entry into the bloodstream through diffusion into pulmonary circulation ( ex. Inhaler)
Intrathecal
Deliver injection fluid filled space between the thin layers of tissue that cover the brain and spinal cord
(Ex. Spinal subarachnoid space)
Allow certain drugs to bypass the blood brain barrier and reach the CNS
For tendon sheath or bursa to treatment
Iv and intra-arterial
Minimize first pass
Iv injection
Resulting in peak levels instantaneously and reach the target site rapidly
Iv cannula (line) allow prolonged and steady diffusion
Intra arterial injection
Relative difficult and dangerous procedure
Occasionally used in chemo to decrease exposure to healthy tissue
Subcutaneous injection
Relatively slower more prolonged release into the systemic circulation
( local anesthesia, insulin and hormonal contraceptive)
Intra muscular injection
Easily accessible
Realities steady prolonged release
Relatively rapid effect while avoiding large increase of plasma seen within the iv
Intra muscular injection
Easily accessible
Realities steady prolonged release
Relatively rapid effect while avoiding large increase of plasma seen within the iv
Transdermal
Absorbed through the dermal layers and into the subcutaneous tissues or the peripheral circulation
Iontophoresis
Use electrical current to deliver medication into the target tissue
Phonophoresis
Deliver the drug with the aid of ultrasound
Bioavalibility
The extent to which the drug reaches the systemic circulation
Ex. If 100 mg of a drug is given orally and 50 mg eventually make it into the systemic circulation the drug is said to be 50% bioavailable
Lipid soluble compounds
(Including most drugs) are able to pass directly through the membrane by dissolving in the lipid bilayer
Drugs will diffuse more readily through the lipid layer in its what type of state ?
Neutral, non ionized state
A weak base drug is absorbed where ?
In the duodenum it becomes nonionized and lipid soluble allowing it to be absorbed in the small intestine
A weak acid drug is absorbed where?
Gets absorbed in the stomach due to the acidic environment going to its neutral and nonionized form
Characteristic of active transports
Carrier specificity
Expenditure of energy (ATP hydrolysis)
Ability to transport substance against a concentration gradient
Facilitated diffusion
Had the features of both active transport and passive diffusion
An assisting protein carrier is present but no net energy is expended
Ex. Skeletal muscle glucose uptake
Passive diffusion
The driving forces WITHOUT EXPENDING any energy are the electrical (charged particles) chemicals and pressure differences on the two sides of the membrane