Lecture 4: Genetics (Routes of Administrations) Flashcards
1
Q
Routes Of Administration
INHALATION
A
- drugs cross into the blood through diffusion
- factors affecting diffusion (pH, polarity, size)
- 7-10 second onset
- 2-4 hours duration
- 5-99% bioavailability
- shortest circulatory path to brain = lungs –> left side of heart –> BBB
- huge surface area for absorption
2
Q
Routes Of Administration
INJECTION
A
- 10-20 second onset
- 2-4 hr durtion
- 100% bioavailability
- 2nd shortest circulatory pth to reach brain - right side of heart –> lungs –> left side of heart –> BBB
- no first-pass metabolism
- absorption into the bloodstream depends on diffusion into tissue and blood flow
- rate of injectio affects oeak height
- veins eventually collapse
3
Q
Routes Of Administration
INSUFFLATION (snorting)
A
- 10-45 min onset
- 5-8 hr duration
- up to 80% bioavaliblity
- longer oathway to BBB
- no first-pass metabolism
4
Q
Routes Of Administration
INGESTION
A
- 20-45 min onset
- 6+ hrs
- 5-99% bioavaibility
- stomach pH can alter chemistry (degrade)
- first-pass metabolism
- irritation emesis
5
Q
Extracting Information From Dose-Response Curves
A
-methand amphetamines (drug most effective)
- meth (most potent)
- TI = LD50/ED50 (morphine)
- TI changes in the presences of other drugs
6
Q
Drug Half-Lives Indicate How Long The Drug Remains In Circulation
A
- half-life =time to remove 50% of drug from circulation
- kinetics describe elimation
- some drugs are excrested unchanged
- kinetics change with repeated use (tolerance)
7
Q
Emergent Findings
A
- neuronal adhesion –> important for plasticity
- DNA/RNA processing transcriptional regulation, cell structure
- addiction is now viewed as a learning disease
(genetics and environment play 50/50 role to produce behavioral phenotypes of addiction)
