Final Flashcards
First pass effect:
Oral, Rectal, Parenteral
How much drug is left for circulation (distribution) after passing through the liver[depends on how much the liver chemically changes to inactive metabolites]
- because of this, oral routes are less effective first time taken.
Oral: has first pass effect
Rectal: may or may not have a first pass effect
Parenteral: no first pass effect
Metabolism:
Where?
Cytochrome p-450 enzyme?
(biotransformation)
-The next step after absorption and distribution
-In the Liver
Cytochrome p-450 enzyme = target lipid soluble drugs which are typically hard to eliminate
Drug that increase the speed of metabolism:
Slow it down:
Speed up: Rifampin, Phenytoin, Barbituates
Slow down: Ketoconazole (antifungal drug)
Absorption:
Movement of a drug from its site of administration into the bloodstream for distribution to tissues
(Parenteral dosage forms that are injected intravenously are immediately placed into solution in the bloodstream and do not have to be dissolved in the body. Therefore, 100% absorption is assumed to occur immediately upon intravenous injection)
Excretion:
- Drugs that have been metabolized by the liver become more polar and water-soluble, makes elimination by kidneys easier.
- In the Kidney
- Biliary excretion: excretion by intestines
- Enterohepatic Recirculation
Agonist:
bind to opioid receptor on the brain (codeine and hydrocodone), causes an action
Agonist-Antagonist (partial agonist):
bind to the pain receptor, causing a weaker pain response (pentazocine & nalbuphine)
-these reach a maximum analgesic effect, and pain doesn’t improve even when you increase the dosage.
Synergistic effect:
1+1 = greater than 2
Adjuvant drugs:
drugs that enhance clinical therapy when used together with another drug
(Used together with general anesthetics for anesthesia initiation, sedation, decrease anxiety and amnesia.)
