Pharma Flashcards
2 methods used to measure the duration of exponential process
Time constant and half/life
After one half life … of the process is still remaining where 2 half life … and 3 half life’s … of process still remaining
50%
25%
12.5%
After one Time constant … of the process remaining, where 2 time constant … and 3 time constant … of the process still remains to complete
37%
12.5%
5%
Time constant for breathing circuit is
Volume of circuit/fresh gas flow rate
Time constant for lungs =
FRC / minute ventilation
Context sensitive half life is …
The time taken for drug concentration to fall by 50% after DC
ED95 means
The dose of drug that is required to produce a specific response in 95% of the population exposed to the drug
ED 95 for NMB
Is the amount of drug needed to decrease the twitch height by 95%
1st order kinetics
Rate of decrease of plasma concentration of the drug depends of plasma concentration of the drug
Zero order kinetics
The plasma concentration of drug decreases at a constant rate
Drug dosing in RF relation to volume of distribution
Volume of distribution is increased and clearance reduced leading to increased loading and dosing interval
Drugs acting on GABA receptors
GABA-A
GABA-B
GABA-A -> Cl channel opening (thiopental, propofol, BZDs, etomidate)
GABA-B -> K channel opening (Baclofen)
Ketamine acts on
noncompetitive antagonist of NMDA Ca channel pore
Baclofen acts on
Agonist of GABA- B receptors both pre and postsynaptic
Ion channels and drugs act on
Ca
Cl
Na
K
Gaba + ketamine -> Ca
Thiopental, propofol, Etomidate -> Cl
Local anesthetic, phenytoin, NMB -> Na
Baclofen -> K
Agents that work on cGMP and cAMP
Nitric oxide
Glucagon, insulin, Epi, NorEpi, milrinone, PGs -> all cAMP
Dose of oral Versed is higher then IV because …
High first pass metabolism in liver
0.5-0.7 mg/kg body weight
Location of brain opioid receptors
Periaqueductal gray matter
Amygdala
Corpus striatum
Hypothalamus
At spinal -> substantia gelatinosa
Clinical effect of mu opioid receptors
Spinal and supraspinal analgesia
RS depression
Physical dependence
Ms rigidity
Clinical effect of kappa opioid receptors
Sedation and spinal analgesia
Clinical effect of delta opioid receptors
Analgesia and behavioral
Clinical effect of sigma opioid receptors
Dysphoria and hallucination
The ceiling effect of Nalbupine is due to ..
It’s partial agonistic activity
What’s the reason of rapid action of Alfentanil? And it’s short duration?
Low pKa
Where it has low VoD and it’s rapid metabolism in liver makes it short duration of action