A provider prescribes phenobarbital for a client who has a seizure disorder. The

medication has a long half-life of 4 days. How many times per day should the nurse

expect to administer this medication?

A. One

B. Two

C. Three

D. Four

A (Medications with long half-lives remain at their therapeutic levels between doses

for long periods of time. The nurse should expect to administer this medication once a

day.)

A staff educator is reviewing medication dosages and factors that influence

medication metabolism with a group of nurses at an in-service presentation. Which of

the following factors should the educator include as a reason to administer lower

medication dosages? (Select all that apply.)

A. Increased renal secretion

B. Increased medication-metabolizing enzymes

C. Liver failure

D. Peripheral vascular disease

E. Concurrent use of medication the same pathway metabolizes

Answer:

C, E

(C. Liver failure decreases metabolism and thus increases the concentration of a

medication. This requires decreasing the dosage.

E. When the same pathway metabolizes two medications, they compete for

metabolism, thereby increasing the concentration of one or both medications. This

requires decreasing the dosage of one or both)