Class #7-Tolerance Flashcards
Biological adaptation to Rx
tolerance, addiction, dependence, withdrawal
Tolerance definition?
No longer respond and or need higher dose to get same effect
Drug addiction =
Substance dependence: physiological and psychological
Can you get dependent to nasal spay?
yes
Studying dependence ways?
- Rat (Eg IV = more rapid dependence)
2. Before on human using heroin (1950s), 20Xtime fold over several months to get same effect.
Dose respond curve of tolerance in rats
Dose respond curve moves to right and max effect is less
Type of tolerance?
Acute : Greater effect as the blood {} is rising. Rapid adaptation of the CNS when a Rx is interfering with the CNS function.
Chronic: Repeated administration causes a decreased response to a test dose
Tolerance pharmacokinetics
Decrease [] at site of action, because increase Enz. activity = increase metabolism. When Rx metabolism is altered as a function of time
Tolerance Pharmacodynamics
decrease effect due to biological adaptation at the site of action. Adaptation of the tissues itselfs. The intrinsic responsivity of the receptor system diminishes over time.
Behavioral tolerance
decrease effect due to conditioned response
Innate tolerance (not used in this class)
Metabolizing enz. differ from one ind. to another.
High is connected to … in brain
Reward system
Resistance to chemotherapy?
Not tolerance in classical term, but cancer cell resist Rx, with different mechanism.
How to know if pharmacokinetics tolerance?
Rx blood {} get same response
How to know if pharmacodynamic tolerance “”?
Tissue is less responsive at same Rx blood {}. So need more of the Rx at site of action for same response.