Drug Detail:Probenecid (Probenecid [ proe-ben-a-sid ])
Drug Class: Antigout agents
Usual Adult Dose for Gout
Therapy should not be started until an acute gout attack has subsided:
Initial: 250 mg orally twice a day for 1 week
Maintenance: 500 mg orally twice a day
- If symptoms of gouty arthritis are not controlled or 24-hour uric acid excretion is not above 700 mg, may increase dose in 500 mg increments every 4 weeks as tolerated; continue at dose that maintains normal serum urate levels
Comments:
- If an acute attack is precipitated during therapy, this drug should be continued at same dose while appropriate therapy is given to control acute attack.
- To prevent crystallization of uric acid in urine, a liberal fluid intake (2 L/day) and alkalization of the urine should be encouraged; alkalization of urine may be relaxed when serum urate levels return to normal limits and tophaceous deposits disappear.
- Maintenance dose may be decreased in increments of 500 mg every 6 months when acute attacks have been absent for 6 months or more and serum urate levels remain within normal limits; maintenance dosage should not be reduced to the point serum urate levels start to rise.
Use: For the treatment of hyperuricemia associated with gout and gouty arthritis.
Usual Adult Dose for Gouty Arthritis
Therapy should not be started until an acute gout attack has subsided:
Initial: 250 mg orally twice a day for 1 week
Maintenance: 500 mg orally twice a day
- If symptoms of gouty arthritis are not controlled or 24-hour uric acid excretion is not above 700 mg, may increase dose in 500 mg increments every 4 weeks as tolerated; continue at dose that maintains normal serum urate levels
Comments:
- If an acute attack is precipitated during therapy, this drug should be continued at same dose while appropriate therapy is given to control acute attack.
- To prevent crystallization of uric acid in urine, a liberal fluid intake (2 L/day) and alkalization of the urine should be encouraged; alkalization of urine may be relaxed when serum urate levels return to normal limits and tophaceous deposits disappear.
- Maintenance dose may be decreased in increments of 500 mg every 6 months when acute attacks have been absent for 6 months or more and serum urate levels remain within normal limits; maintenance dosage should not be reduced to the point serum urate levels start to rise.
Use: For the treatment of hyperuricemia associated with gout and gouty arthritis.
Usual Adult Dose for Adjunct to Antibiotic Therapy
500 mg orally 4 times a day
Comment: The Centers for Disease Control and Prevention (CDC) no longer recommend this drug with oral cephalosporins or ampicillin as a treatment for gonococcal infections.
Use: As an adjuvant to therapy with penicillin or with ampicillin, methicillin, oxacillin, cloxacillin, or nafcillin, for elevation and prolongation of plasma levels by whatever route the antibiotic is given.
Usual Pediatric Dose for Adjunct to Antibiotic Therapy
Age: 2 to 14 years and weight less than 50 kg:
Initial: 25 mg/kg (or 0.7 g/m2 ) orally once
Maintenance: 40 mg/kg (or 1.2 g/m2/) per day orally administered in 4 equally divided doses 4 times a day
Weight greater than 50 kg:
500 mg orally 4 times a day
Comment: The Centers for Disease Control and Prevention (CDC) no longer recommend this drug with oral cephalosporins or ampicillin as a treatment for gonococcal infections.
Use: As an adjuvant to therapy with penicillin or with ampicillin, methicillin, oxacillin, cloxacillin, or nafcillin, for elevation and prolongation of plasma levels by whatever route the antibiotic is give.
Renal Dose Adjustments
Gout:
- Chronic renal insufficiency (CrCl less than 30 mL/min): Not recommended as it may not be effective
- Renal impairment: Use caution; dosage requirements may be increased in some patients with some renal impairment
Adjunct to penicillin:
- Not recommended in conjunction with penicillin in the presence of known renal impairment.
- If used in elderly patients with renal impairment, use caution, dose reduction may be warranted, specific guidelines are not provided
Liver Dose Adjustments
Data not available
Dose Adjustments
Urine alkalization:
- A liberal fluid intake (2 L/day) and alkalization of the urine is recommended when excretion of uric acid is at a high level; alkalization may be relaxed when serum urate levels return to normal and tophaceous deposits disappear.
- Sodium bicarbonate 3 to 7.5 g/day or potassium citrate 7.5 g/day may be used to maintain an alkaline urine.
- Acid-base balance should be watched carefully when alkali is administered.
Adjunct to antibiotic:
Phenolsulfonphthalein (PSP) excretion test may be used to determine the effectiveness of probenecid in retarding penicillin excretion and maintaining therapeutic levels; the renal clearance of PSP is reduced to about one-fifth the normal rate when dosage of probenecid is adequate.
Precautions
Contraindicated in children less than 2 years of age
Consult WARNINGS section for additional precautions.
Dialysis
Data not available
Other Comments
Administration advice:
Take orally
Gout:
- Maintain adequate hydration (at least 2 L/day) and alkalization of the urine with sodium bicarbonate or potassium citrate as needed.
Storage requirements:
- Protect from light
General:
- Gastric intolerance may be indicative of toxicity and can be corrected by decreasing dosage.
- This drug should not be started until an acute gouty attack has subsided; if an acute attack is precipitated during therapy, this drug should be continued at same dose while appropriate therapy is given to control acute attack.
- This drug inhibits the tubular secretion of penicillin and usually increases penicillin plasma levels 2 to 4 fold.
Monitoring:
Gout:
- Monitor serum urate levels as needed to determine adequacy of treatment
- Monitor acid-base balance in patients administered alkali.
Patient advice:
- Instruct patients on the need for adequate hydration, alkalization of the urine, and/or dietary restrictions appropriate to their care.
- Inform patients that salicylates may diminish the uricosuric effect of this drug; if a mild analgesic agent is needed, acetaminophen should be used.