Answer to Practice Problem #1 Hepatic Clearance Tutorial:

 

Since diazepam is a low CL_int drug, we know that CL_H = f_ubCL_uint. Cimetidine is an enzyme inhibitor, which will decrease CL_uint. This will result in a decrease in the CL_H and consequently an increase in t_1/2. This will lead to the appearance of the curve with a dotted line. After intravenous administration, the peak will not change, since this is a function of the volume of distribution and dose. The elimination rate will be reduced, resulting in a less steep decline in the concentration. After oral administration, the reduction in the elimination rate will lead to a later t_max and an increased C_max, as is shown on the curve.

 

 

 

How would intensity, onset, and duration of action be influenced by co-administration of cimetidine? Answer

 

Last revised 07/13/05

 

ã 2005 -  Craig K. Svensson, Pharm.D., Ph.D.

 

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