The client has a clinic appointment scheduled 10 days after discharge. Which laboratory finding at that time would indicate that allopurinol (Zyloprim) has had a therapeutic effect?
A. Decreased urinary alkaline phosphatase level
B. Increased urinary calcium excretion
C. Increased serum calcium level
D. Decreased serum uric acid level
Correct Answer: D. Decreased serum uric acid level
By inhibiting uric acid synthesis, allopurinol decreases its excretion. The drug’s effectiveness is assessed by evaluating for a decreased serum uric acid concentration. Allopurinol undergoes metabolism in the liver, where it transforms into its pharmacologically active metabolite, oxypurinol. The half-life of allopurinol is 1 to 2 hours, and oxypurinol is about 15 hours.
Option A: Alkaline phosphatase levels are not altered by allopurinol. Both allopurinol and oxypurinol are renally excreted. Allopurinol and oxypurinol both inhibit xanthine oxidase, an enzyme in the purine catabolism pathway that converts hypoxanthine to xanthine to uric acid.
Option B: It does not affect calcium excretion. In patients with renal insufficiency (chronic kidney disease stage 4 and greater), allopurinol should start at 50 mg daily dose, and the dose shall be escalated by 50 mg every 2 to 5 weeks until reaching the target serum uric acid.
Option C: Allopurinol does not alter the level of alkaline phosphatase, nor does it affect urinary calcium excretion or the serum calcium level. Complete blood count, liver function tests, renal function, and serum uric acid levels shall be measured every 2 to 5 weeks while titrating the dose until achieving target serum uric acid level and every six months after that.
No comments:
Post a Comment