Category:Antigout agents

An antigout agent is a medicine used to treat acute attacks of gout (the inflammatory monoarthritis triggered by monosodium urate crystal deposition in joints) or to lower serum urate concentrations chronically (urate-lowering therapy, ULT) to prevent recurrence and to resolve tophaceous deposits. The category divides cleanly into the acute-attack medicines (the non-steroidal anti-inflammatory medicines, colchicine, systemic corticosteroids, the IL-1 antagonists for refractory cases) and the chronic urate-lowering medicines (the xanthine oxidase inhibitors allopurinol and febuxostat, the uricosuric medicines probenecid and benzbromarone and lesinurad, and the recombinant uricase pegloticase for refractory tophaceous gout).

The pharmacological history of gout is unusually long. Hippocrates wrote of the "unwalkable disease" in the fifth century BCE; the Celsus description of inflammatory arthritis in the first century is recognisable; the English physician Thomas Sydenham published his Tractatus de Podagra et Hydrope in 1683, one of the most precise clinical descriptions of gout ever written, drawn from his own suffering of the disease. The chemical recognition of uric acid in renal calculi by William Hyde Wollaston in 1797 and its identification by Wollaston in 1813 as the substance of gouty tophi established the biochemical foundation of the disease;^[1] the demonstration by Alfred Garrod in 1848 that gout patients had elevated serum uric acid (by his "thread test" using a thread suspended in serum to crystallize uric acid) closed the diagnostic argument and gave the framework that has persisted to the present.

The acute-gout medicines have all been used for centuries in some form. Colchicine, extracted from the autumn crocus Colchicum autumnale by Pelletier and Caventou in 1820, has been used for acute gout in some form since the Byzantine era (Alexander of Tralles in the sixth century described the use of Colchicum). Colchicine's antigout mechanism (microtubule disruption that inhibits neutrophil chemotaxis and crystal-driven inflammasome activation) was elucidated in the twentieth century, but the medicine had been used effectively for fifteen hundred years before that. The narrow therapeutic window (gastrointestinal toxicity at doses near the therapeutic) and the substantial interaction profile (CYP3A4 substrate; severe toxicity with concurrent clarithromycin or grapefruit) shape its contemporary use. The 2010 FDA approval of branded colchicine (Colcrys, URL Pharma) at much higher cost than the unbranded preparation was a controversial regulatory episode; the medicine returned to generic competition in 2014.

The non-steroidal anti-inflammatory medicines (described under NSAIDs and non-opioid analgesics) became standard first-line treatment for acute gout in the post-1971 (Vane prostaglandin-mechanism) era; indomethacin, naproxen, ibuprofen, and the COX-2-selective celecoxib are all effective at full anti-inflammatory doses for 5 to 7 days. Systemic corticosteroids (oral prednisone 30-40 mg daily for 5-7 days; intraarticular triamcinolone or methylprednisolone) provide equivalent efficacy with a different adverse-effect profile and are first-line for patients in whom NSAIDs or colchicine are contraindicated. The IL-1 antagonists (anakinra, canakinumab, rilonacept) are reserved for refractory cases or patients in whom all of the above are contraindicated, on the basis of the central role of the NLRP3 inflammasome and IL-1β in crystal-driven gout inflammation.

The urate-lowering medicines are the more transformative class. Allopurinol, synthesised by Gertrude Elion and George Hitchings at Burroughs Wellcome in 1956 as a candidate antineoplastic, was found in 1963 to inhibit xanthine oxidase (the enzyme that produces uric acid from xanthine and hypoxanthine) and to reduce serum urate.^[2] Allopurinol has been the standard urate-lowering medicine for sixty years; its limitations are the rare but devastating allopurinol-hypersensitivity-syndrome (Stevens-Johnson syndrome and toxic epidermal necrolysis, with the HLA-B*58:01 association in Han Chinese, Thai, and Korean populations making pharmacogenomic screening before initiation now standard in those populations), and the dose-titration requirement to a serum-urate target below 6 mg/dL.

The non-purine selective xanthine oxidase inhibitor febuxostat (Adenuric in Europe, Uloric in U.S., Teijin/Takeda 2008) provides an alternative for patients intolerant of allopurinol; its CARES-trial cardiovascular safety signal (a small but real excess of cardiovascular death versus allopurinol in patients with established cardiovascular disease) has restricted its use to allopurinol-intolerant patients. The uricosuric medicines probenecid (developed in 1949 as a penicillin-sparing agent, then repurposed for gout) and benzbromarone (Europe) increase urinary urate excretion through inhibition of the renal proximal-tubule URAT1 transporter. The newer uricosuric lesinurad (Zurampic/Duzallo, AstraZeneca 2016) was withdrawn in 2019 over commercial considerations; verinurad and dotinurad are in development. The recombinant porcine uricase pegloticase (Krystexxa, Horizon/Amgen 2010) provides intravenous urate-lowering for severe refractory tophaceous gout; its substantial infusion-reaction rate has restricted its use to specialty centres, and the addition of methotrexate as concurrent immunosuppression substantially improved tolerability (the MIRROR trial 2022).

The contemporary management of gout follows a structured pathway: acute-attack control with one of the three first-line medicines, choice guided by comorbidities; chronic urate-lowering therapy initiated 2-4 weeks after the attack has settled (or during the attack with concurrent prophylaxis), with a treat-to-target approach to serum urate below 6 mg/dL (below 5 mg/dL in patients with tophi); and prophylaxis against urate-lowering-flare with low-dose colchicine or NSAID for the first 3-6 months of urate-lowering therapy. The 2022 ACR guidelines emphasised that urate-lowering therapy is indicated in all patients with two or more gout flares per year, with tophi, with documented urate crystal-related joint damage, or with a history of urolithiasis.

By indication and mechanism:

• Acute attack:
  • NSAIDs (cross-indexed): indomethacin, naproxen, ibuprofen, celecoxib
  • Microtubule poison: colchicine (Colcrys, Mitigare)
  • Systemic and intra-articular corticosteroids (cross-indexed): prednisone, methylprednisolone, triamcinolone
  • IL-1 antagonists (refractory cases; cross-indexed under biologics / immunomodulators): anakinra (off-label), canakinumab (approved for refractory gout in Europe), rilonacept
• Chronic urate-lowering:
  • Xanthine oxidase inhibitors: allopurinol (first-line; HLA-B*58:01 testing in Asian populations), febuxostat (second-line, allopurinol-intolerant), topiroxostat (Japan)
  • Uricosurics: probenecid (also as antibiotic-sparing agent), benzbromarone (Europe), lesinurad (withdrawn 2019)
  • Recombinant uricase: pegloticase (intravenous, refractory tophaceous gout, with methotrexate concurrent immunosuppression)
  • Investigational: verinurad, dotinurad, ulodesine

The boundary of this category is "medicine prescribed primarily to treat gout (acute attack or chronic prevention)." The medicines used in pseudogout (calcium pyrophosphate deposition disease) are largely the same anti-inflammatory medicines but with no specific urate-lowering analogue and are cross-listed where appropriate. The medicines used in tumor lysis syndrome (rasburicase, the recombinant uricase for acute prevention; allopurinol for prevention; aggressive intravenous hydration) overlap with this category for the urate-lowering portion but are listed under their oncologic-supportive-care primary indication. The medicines that secondarily cause hyperuricemia (thiazide diuretics, low-dose aspirin, niacin, cyclosporine, tacrolimus) are noted as risk factors but are not antigout medicines.

This category page is an encyclopedia article about its subject. The actual index of medicines belonging to the category is generated automatically by the wiki engine, from category-membership declarations on the individual medicine pages, and appears at the foot of the page below the references.