gout pharm probenacid vs allopurinol **nbme 6 ref - whatsfordinner

[ArchivalUser]

as far as i know, probenecid is a uricosuric agetn which inhibits resorbtion of uric acid in pct thus increase excretion, its contraindication is that you dont use it in renal failure

and allopurinol - xanthine oxidase inhib - decrease xanthine to uric acid, minimal increase in excretion of uric acid

my question is - when renal status is NOT compromised - normal renal function - which would you choose and why?
refernce for this qeustion is NBME 6 question 18
A 57 yr old man comes to the physician coz of 1 day h/o swelling and severe pain of his rite knee that worsens w/ movement of the knee. He has no h/o serious illness. Temp-98.9, pulse-80, resp- 16, bp- 138/78. Examination of rt knee shows warmth, erythema, diffuse tenderness and moderate effusion. Aspiration of knee jt reveals cloudy fluid, fluid analysis shows WBC count 9000. Microscopic exam shows negatively birefringent, needle shaped crystals. Which is most appropriate initial pharmacotherapy?

A-Allopurinol
B-Hydroxychloroquine
C-Indomethacin
D-Prednisone
E-probenecid

any thoughts

[ArchivalUser]

so basically when given both options, when would you choose probenecid and when would you choose allopurinol?

[ArchivalUser]

nvm, sarim answered my question a few months ago!! i guess he knew id ask!
sarim - 06/04/13 14:42

correction: urinary uric acid excretion is 80 mg/day ------- 800 mg/day


Gout Tx:

*Is it "Acute attack" ?

*If not an Acute attack (as in the stem, "One Wk After the Acute attack") Then How we Prevent Future acute attacks ?

A-If problem is "Underexcretion" (Renal Problem)-->Then we give Uricosuric agents
B-If problem is "Overproduction"---------------->Then we give agents that block the Synthesis



NOTE:
Uricosuric agents(e.g. probenecid) are Contraindicated in a pt who is Hyperuricosuric , as it can promote formation of "Uric Acid Crystals"




"Her 24 hour urinary uric acid excretion is 800 mg/day [normal = 300-600mg/day]."

so Is the problem in our pt is due to Underexcretion or Overproduction ?