1. Tilidine is a narcotic analgesic which can be abused by
drug addicts when taken in high doses. Naloxone is an opiate
antagonist which blocks the action of tilidine. It is known
to undergo a saturable first pass effect. What is the
rationale for a drug combination tilidine/naloxone (valoron)?
2. Administration of phenobarbital (60 mg daily) to a
patient receiving dicumarol (75 mg daily) chronically,
reduces the plasma concentration of the anticoagulant (black
circle) and the prothrombin (open circle) time, a measure of
its effect on the concentration of the vitamin k1-dependent
What kind of pharmacokinetic interaction is responsible
for the observed pharmacodynamic interaction? Explain your
3. Discuss following statement:
For drugs with a hepatic extraction ratio of 1, the
hepatocyte does not represent a strong diffusion barrier.
4. Select for the following physiological changes the
induced change on the pharmacokinetic parameters for a
lipophilic, protein bound, low extraction drug cleared by
liver and kidney.
5. Mark whether the following statements are True or False
metabolism is one example of the first-pass effect.
enterohepatic recycling can prolong drug activity in the
obstruction decreases the half-life of a drug subject to
drugs only pass through the liver once.
hepatic blood flow is reduced, more drug will get
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