941.Which of the following are antagonist and agonist pairs for the same receptor
A.butoxamine, terbutaline
B.phenyoxybenzamine, cyclopentolate
C.pilocarpine, bethanechol
D.oxymetazoline, dobutamine
E.bromocriptine, pranipexole
942.Which is false
A.Drug A with a higher potency can have a lower efficacy than drug B
B.Drug A with a higher affinity for its receptor has a higher potency
C.Drug A with a lower potency must have a lower efficacy than drug B
D.Drug A with a higher potency can still have the same efficacy
E.None of the above
943.Regarding 1stpass metabolism
A.its effect on bioavailability is expressed as the extraction ratio where ER = CL (liver)/Q(liver)
B.it affects the volume of distribution
C.it reduces the bioavailability of oral morphine to 15%
D.the extraction ratio of phenytoin is higher
E.it makes it impossible to attain therapeutic levels of lignocaine using oral dosage
944.Clearance
A.Is the amount of drug eliminated / concentration of the drug
B.Is constant for most drugs in the clinical setting at therapeutic levels
C.Is very high for lithium
D.Is independent of concentration for phenytoin
E.Is inversely proportional to volume of distribution
945.Volume of distribution
A.Is inversely proportional to clearance
B.Is measured in mg/L
C.Is used to work out the maintenance dose
D.Is high in Warfarin
E.Is proportional to half life
946.5mL of2% wv is equal to
A.10mg
B.100mg
C.200mg
D.20mg
E.40mg
947.Spare receptors
A.Do not affect the sensitivity to drugs
B.Are the result of low efficiency of receptor-effector interaction
C.Are present when the maximal response is achieved when occupancy is not full
D.Are qualitatively different from non-spare receptors
E.May be hidden
948.The drug with the highest first pass metabolism is
A.Chlorpropamide
B.Diazepam
C.Verapamil
D.Theophylline
E.Warfarin
949.Loading dose
A.Is inversely proportional to volume of distribution
B.Is proportional to accumulation factor
C.Is independent of rate of administration to multicompartment pharmacokinetics
D.Equal target concentration x accumulation factor
E.Of Theophyllineadministered IV in a normal 70kg man = 100mg
950.Half life
A.Is not a useful parameter in drug dosage
B.Depends on the volume of distribution and the clearance of a drug
C.Is defined as the time required for a third of the drug to be eliminated
D.Does not vary with age
E.Is not altered with certain disease states