Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
SULFINPYRAZONE vs PROBENECID
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
Competitive inhibitor of tubular organic anion transport, increasing uric acid excretion; also inhibits platelet aggregation.
Inhibits renal tubular reabsorption of uric acid, increasing its excretion and lowering serum urate levels. Also inhibits renal tubular secretion of weak acids (e.g., penicillins, cephalosporins).
Chronic gouty arthritis,Hyperuricemia,Off-label: Prevention of gout flares during initiation of allopurinol
FDA: Treatment of hyperuricemia associated with gout (prophylaxis and chronic management), adjunct to penicillin or cephalosporin therapy to elevate and prolong antibiotic levels.,Off-label: Prevention of nephropathy in patients with hyperuricemia, adjunct to antiviral agents (e.g., cidofovir) to reduce nephrotoxicity.
100-200 mg orally twice daily, initially, then increase to 200-400 mg twice daily.
Oral: 250 mg twice daily for 1 week, then 500 mg twice daily; for gout prophylaxis, initial 250 mg twice daily for 3-4 weeks then increase to 500 mg twice daily; for hyperuricemia secondary to thiazide diuretics, 250 mg twice daily.
2-5 hours (terminal elimination half-life; prolonged in renal impairment to up to 10 hours)
Terminal elimination half-life is approximately 6-12 hours in adults with normal renal function; may be prolonged in renal impairment or older adults.
Primarily hepatic via oxidation and conjugation; major metabolite is sulfinpyrazone sulfide.
Primarily hepatic via oxidation and glucuronidation; minor renal metabolism.
Renal: ~90% (50% unchanged, 50% as glucuronide and other metabolites); Biliary/fecal: ~10%
Renal excretion of unchanged drug and metabolites; ~77% of dose recovered in urine within 48 hours (50% as glucuronide conjugates, 27% as unchanged probenecid); ~11% excreted in feces via biliary elimination.
98-99% (primarily to albumin)
Approximately 75-95% bound to plasma albumin.
0.15-0.25 L/kg (low Vd, consistent with high protein binding and limited tissue distribution)
Apparent volume of distribution is about 9 L (approximately 0.13 L/kg in adults); indicates limited extravascular distribution, primarily confined to plasma and extracellular fluid.
Oral: 80-90% (well absorbed; decreased with food)
Oral bioavailability is nearly complete (>90%) with peak plasma concentrations achieved within 2-4 hours.
GFR >50 m L/min: no adjustment. GFR 10-50 m L/min: reduce dose by 50%. GFR <10 m L/min: avoid use.
GFR 10-50 m L/min: 250 mg once daily or 500 mg every 12-24 hours; GFR <10 m L/min: avoid use; anuria: contraindicated.
Child-Pugh A: no adjustment. Child-Pugh B: reduce dose by 50%. Child-Pugh C: avoid use.
No specific adjustment recommended; use caution in severe hepatic impairment.
Safety and efficacy not established; use not recommended.
For gout or hyperuricemia (children >2 years): 25 mg/kg/day (max 2 g/day) divided every 6-8 hours; as adjunct to penicillin/cephalosporin: 25 mg/kg/day (max 2 g/day) divided every 8 hours for infants >3 months and children; neonates: dose not established.
Start at lower end of dosing range (100-200 mg daily) and titrate cautiously due to increased risk of renal impairment and drug interactions.
Start at lowest dose (250 mg once daily) due to age-related renal impairment; monitor renal function regularly; avoid if GFR <30 m L/min.
None.
None.
Risk of acute gouty attacks during initial therapy,Uricosuric effect may lead to urolithiasis; maintain adequate hydration and urine alkalinization,Possible cross-allergenicity with sulfonamides,Monitor renal function and complete blood counts
Use with caution in patients with peptic ulcer disease.,May worsen acute gouty arthritis; prophylactic colchicine or NSAIDs recommended during initiation.,Risk of uric acid stone formation; ensure adequate hydration and alkalinize urine if needed.,Avoid use in patients with blood dyscrasias or bone marrow depression.,May interfere with urine glucose and ketone tests.
Active peptic ulcer disease,Known hypersensitivity to sulfinpyrazone or sulfonamides,Severe hepatic or renal impairment
Hypersensitivity to probenecid or any component.,Severe renal impairment (Cr Cl <50 m L/min) or anuria.,History of uric acid kidney stones.,Concomitant use with methotrexate (increases methotrexate toxicity).,Use during acute gouty attack (unless already on therapy).
Avoid high-purine foods (e.g., organ meats, anchovies, sardines, beer) as they may reduce efficacy. Maintain adequate hydration; alcohol consumption should be minimized as it can increase uric acid levels.
Avoid high-purine foods (organ meats, sardines, anchovies, shellfish, red meat) as they increase uric acid levels. Limit alcohol, especially beer and spirits, which increase uric acid. Maintain high fluid intake (water, citrus juices) to promote urine flow and prevent stones. Avoid cranberry juice as it may acidify urine.
Sulfinpyrazone is contraindicated in pregnancy. Animal studies have shown teratogenic effects, and there are no adequate human studies. First trimester exposure may carry a risk of congenital malformations. Second and third trimester use may cause adverse fetal effects including premature closure of the ductus arteriosus, oligohydramnios, and renal dysfunction.
Probenecid is FDA Pregnancy Category B. Animal studies have not demonstrated fetal risk, but no adequate human studies exist. Use only if clearly needed. First trimester: No known teratogenic effects. Second and third trimesters: No specific fetal risks documented; avoid near term due to potential for neonatal hyperbilirubinemia (displaces bilirubin from albumin).
Sulfinpyrazone is excreted into breast milk in small amounts. The M/P ratio is unknown. Due to the risk of serious adverse reactions in nursing infants, including the potential for kernicterus in jaundiced infants, use during breastfeeding is not recommended.
Probenecid is excreted into breast milk in low concentrations; M/P ratio not available. Consider benefits of breastfeeding versus potential risk of adverse effects in infant (e.g., rash, gastrointestinal effects). Use with caution.
No specific dose adjustments have been established. Due to increased renal blood flow and glomerular filtration rate during pregnancy, pharmacokinetics may be altered, but no dose recommendations are available. Sulfinpyrazone is not recommended for use in pregnancy.
No formal pharmacokinetic studies during pregnancy. Dose adjustment not routinely recommended, but consider decreased efficacy due to increased renal clearance in pregnancy. Monitor clinical response and adjust dose if needed.
Sulfinpyrazone is a uricosuric agent used for chronic gout; avoid in acute gout attack. Monitor renal function and uric acid levels. Contraindicated in peptic ulcer disease due to GI irritation. May potentiate warfarin and sulfonylureas; adjust doses accordingly.
Probenecid inhibits renal tubular secretion of uric acid, increasing its excretion; used for chronic gout, not acute attacks. It also reduces renal excretion of penicillins and cephalosporins, so it is used to increase serum levels of these antibiotics. Ensure adequate hydration (at least 2-3 L daily) to prevent urate nephropathy. Avoid in patients with creatinine clearance <50 m L/min, history of uric acid stones, or acute gout attack. Alkalinization of urine (urine p H 6.5-7) reduces stone risk. Monitor serum uric acid, renal function, and CBC. Drug interactions: potentiates toxicity of methotrexate, NSAIDs, thiazides, salicylates (salicylates antagonize uricosuric effect).
Take with food or milk to reduce GI upset.,Drink plenty of fluids (at least 2-3 liters daily) to prevent kidney stones.,Avoid aspirin and other salicylates as they reduce effectiveness.,Report any signs of bleeding, bruising, or abdominal pain immediately.,Do not stop abruptly; discuss with your doctor.
Take probenecid with food or antacids to reduce GI upset.,Drink at least 8-10 glasses of water daily while on this medication.,Do not take aspirin or other salicylates; they can reduce the effect.,This drug may increase bleeding risk if you take blood thinners like warfarin.,Report any signs of allergic reaction, rash, or fever immediately.,Avoid alcohol as it increases uric acid levels.,Tell your doctor before taking other medications, especially antibiotics.,Do not use during an acute gout attack; wait until attack resolves.,May cause dizziness or drowsiness; avoid driving until you know how it affects you.,Store at room temperature, away from moisture and heat.
"Tolvaptan, a vasopressin V2 receptor antagonist, may increase the serum concentration of sulfinpyrazone, a uricosuric agent, primarily through inhibition of OATP1B1/1B3 and possibly other hepatic uptake transporters. This interaction can lead to elevated sulfinpyrazone levels, raising the risk of adverse effects such as renal impairment or hypersensitivity reactions. Careful monitoring and dose adjustment of sulfinpyrazone are recommended when coadministered with tolvaptan."
"Rifaximin, a non-systemic antibiotic primarily acting in the gastrointestinal tract, is a substrate of P-glycoprotein (P-gp) and may induce P-gp expression. Sulfinpyrazone, a uricosuric agent and P-gp inhibitor, can increase the bioavailability and systemic exposure of rifaximin by inhibiting its efflux transport. This interaction may lead to elevated rifaximin serum concentrations, potentially increasing the risk of systemic adverse effects such as Clostridioides difficile infection or hepatic impairment, though clinical data on this specific combination are limited."
"Colchicine may increase the serum concentration of sulfinpyrazone, a uricosuric agent, potentially enhancing its therapeutic effect and risk of toxicity. This interaction is likely mediated by colchicine's inhibition of hepatic cytochrome P450 enzymes and/or interference with biliary excretion of sulfinpyrazone. Clinically, this could lead to elevated sulfinpyrazone levels, increasing the risk of adverse effects such as gastrointestinal disturbances, hypersensitivity reactions, or renal impairment."
"Edoxaban, a direct factor Xa inhibitor, may inhibit organic anion transporters (OATs) involved in the renal excretion of probenecid, leading to increased probenecid plasma concentrations. Elevated probenecid levels can enhance its uricosuric effect and potentially increase the risk of adverse effects such as gastrointestinal disturbances and hypersensitivity reactions. Clinicians should be aware of this interaction when coadministering these agents, particularly in patients with renal impairment."
"Acemetacin, a nonsteroidal anti-inflammatory drug (NSAID) and prodrug of indomethacin, reduces renal clearance of probenecid by inhibiting tubular secretion and possibly competing for organic anion transporters. This leads to increased plasma concentrations of probenecid, prolonging its half-life and enhancing its uricosuric effect. Clinically, this interaction may result in elevated risk of probenecid toxicity, including gastrointestinal discomfort, rash, or rare blood dyscrasias, while also potentially increasing the anti-inflammatory effects of acemetacin."
"Cilostazol, a phosphodiesterase III inhibitor, can inhibit the renal tubular secretion of probenecid, a uricosuric agent, thereby decreasing its clearance and increasing its serum concentration. This elevation may potentiate the effects and toxicity of probenecid, including an increased risk of uric acid nephropathy and gastrointestinal disturbances. The interaction is of particular concern in patients with renal impairment or those receiving concurrent nephrotoxic drugs."
Explore head-to-head clinical comparisons of other medications in the same therapeutic classes.
Common clinical questions about SULFINPYRAZONE vs PROBENECID, answered by our medical review team.
SULFINPYRAZONE is a Uricosuric that works by Competitive inhibitor of tubular organic anion transport, increasing uric acid excretion; also inhibits platelet aggregation.. PROBENECID is a Uricosuric that works by Inhibits renal tubular reabsorption of uric acid, increasing its excretion and lowering serum urate levels. Also inhibits renal tubular secretion of weak acids (e.g., penicillins, cephalosporins).. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between SULFINPYRAZONE and PROBENECID depend on the specific clinical indication. These are both Uricosuric agents and are not directly interchangeable by dose. A physician or clinical pharmacist should guide any therapeutic switching decisions.
The standard adult dose of SULFINPYRAZONE is: 100-200 mg orally twice daily, initially, then increase to 200-400 mg twice daily.. The standard adult dose of PROBENECID is: Oral: 250 mg twice daily for 1 week, then 500 mg twice daily; for gout prophylaxis, initial 250 mg twice daily for 3-4 weeks then increase to 500 mg twice daily; for hyperuricemia secondary to thiazide diuretics, 250 mg twice daily.. Dosing should always be individualized based on indication, renal and hepatic function, age, and other patient factors.
No direct drug-drug interaction has been formally documented between SULFINPYRAZONE and PROBENECID in current clinical databases. However, individual patient risk factors including other medications, organ function, and comorbidities should always be evaluated by a qualified healthcare provider.
The maternal-fetal safety profiles differ. SULFINPYRAZONE is classified as Category A/B. Sulfinpyrazone is contraindicated in pregnancy. Animal studies have shown teratogenic effects, and there are no adequate human studies. First trimester exposure may carry a risk of. PROBENECID is classified as Category A/B. Probenecid is FDA Pregnancy Category B. Animal studies have not demonstrated fetal risk, but no adequate human studies exist. Use only if clearly needed. First trimester: No known . Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.