Gout medications: a review of drug groups

The primary goal of drug therapy for gout is twofold. First, the acute inflammatory attack must be quickly and safely suppressed. Then, uric acid levels must be maintained below target levels over the long term to dissolve crystals and stop attacks. This approach is called the "treat to target" strategy. For most patients, the target level is below 6 mg/dL. In patients with tophaceous lesions and frequent relapses, it is reasonable to aim for levels below 5 mg/dL. This is not a wish list, but a strategic goal that reduces the risk of further attacks and joint destruction. [1]

Long-term urate-lowering therapy is not prescribed to everyone, but rather for clear indications. Priority indications include tophi, frequent attacks, radiographically confirmed joint damage, and concomitant moderate to severe chronic kidney disease. The first choice for most patients is allopurinol, titrated to the target level, including those with chronic kidney disease. [2]

It's important to understand the limitations of diet. Diet alone is rarely able to sustainably maintain uric acid levels at target levels. Therefore, long-term urate-lowering medication will almost always be required. This is now explicitly stated in modern guidelines. [3]

Finally, when starting urate-lowering therapy, triggered attacks are almost inevitable. This is a normal reaction to the crystals "swinging." To help manage this period calmly, prophylactic low-dose anti-inflammatory medications are prescribed for 3-6 months, or longer if necessary. [4]

Relief of an acute attack of gout

In the first few hours, rapid anti-inflammatory action is key. Three effective options are available: nonsteroidal anti-inflammatory drugs, low-dose colchicine, and glucocorticosteroids. The choice depends on contraindications, the stage of chronic kidney disease, concomitant medications, and the number of affected joints. In monoarthritis, intra-articular glucocorticosteroids often provide the most rapid effect. [5]

Colchicine is effective in low doses when started within the first 24-36 hours. The classic modern regimen is a loading dose followed by another small dose an hour later, followed by a short maintenance course of 1-2 doses per day for several days. High "old" doses are not used due to toxicity. [6]

Nonsteroidal anti-inflammatory drugs (NSAIDs) relieve pain and swelling, but require stomach protection and consideration of the risk to the kidneys and heart. In practice, standard anti-inflammatory doses are used for 5-7 days, followed by a rapid reduction. [7]

Systemic glucocorticosteroids are appropriate when other options are contraindicated and in polyarthritis. A short course with gradual tapering or a single intra-articular injection for isolated lesions is often used. [8]

Table 1. Relief of a gout attack: dosage guidelines

Class	Drug and typical regimens	Key points
Colchicine	1.2 mg once, after 1 hour 0.6 mg, then 0.6 mg 1-2 times a day for 2-3 days	Start as early as possible. Adjust for chronic kidney disease. Monitor for interactions with CYP3A4 and P-gp inhibitors. [9]
Nonsteroidal anti-inflammatory drugs	For example, naproxen 500 mg 2 times a day, indomethacin 50 mg 3 times a day, etoricoxib 120 mg 1 time per day, course 3-7 days	Consider the risk to the stomach, kidneys, and heart. Add a proton pump inhibitor if there is a risk of gastropathy. [10]
Glucocorticosteroids	Oral prednisolone in a short course or intra-articular triamcinolone for monoarthritis	Preferably in cases of contraindications to colchicine and non-steroidal drugs, as well as in cases of polyarthritis. [11]
Interleukin 1 inhibitors	Canakinumab for frequent attacks when standard treatments are not appropriate	Specialized appointment for strict indications. [12]

Prevention of attacks when starting urate-lowering therapy

To avoid a relapse into a series of painful attacks after starting urate-lowering medications, prophylaxis with low doses of anti-inflammatory drugs is prescribed. The most studied option is colchicine at a low daily dose for 3-6 months, sometimes longer, until uric acid levels are consistently below target. An alternative is low doses of nonsteroidal anti-inflammatory drugs or low doses of oral glucocorticosteroids if colchicine is contraindicated. [13]

Doses are selected individually, taking into account glomerular filtration rate and drug interactions. Colchicine should not be combined with strong CYP3A4 and P-gp inhibitors in patients with renal or hepatic impairment due to the risk of life-threatening toxic reactions. [14]

The patient must understand that prophylaxis is a temporary bridge through the "turbulent" period of the first few months. Urate-lowering therapy should not be discontinued because of an attack. The attack must be treated separately and titration to the target should be continued. [15]

Uric acid levels are monitored monthly during the titration phase and at least annually after reaching the target. This improves adherence and allows for timely adjustments to the regimen. [16]

Table 2. Prevention of attacks when starting urate-lowering therapy

Option	Typical doses	When to choose
Colchicine	0.5-0.6 mg 1-2 times a day for 3-6 months	Basic option with preserved renal function and no dangerous interactions. [17]
Nonsteroidal anti-inflammatory drugs	Low-dose naproxen with gastric protection	In case of colchicine intolerance and low cardiorenal risk. [18]
Low dose oral glucocorticosteroid	Individual and short-term	If both previous options are contraindicated. [19]

Long-term urate-lowering therapy

Xanthine oxidase inhibitors are the mainstay of treatment. Allopurinol is the first choice for most patients, including those with chronic kidney disease. They start with a low dose and increase it every 2-4 weeks until the target uric acid level is reached. Maximum doses are higher than often thought and are safe to use with regular monitoring. [20]

Febuxostat is an alternative for patients intolerant to allopurinol or ineffective at maximum doses. The issue of cardiac safety was discussed following the CARES trial, which demonstrated increased mortality with febuxostat in patients with established cardiovascular disease, leading to warnings in the package insert. The later FAST trial demonstrated non-inferiority to allopurinol in a selected cohort of patients with cardiovascular safety, but these data are interpreted with caution. The decision is made on an individual basis, taking into account the risk profile. [21]

Uricosurics increase renal excretion of uric acid. Probenecid is used when xanthine oxidase inhibitors are ineffective or intolerable, provided there is no nephrolithiasis and renal function is intact. Benzbromarone is restricted in some countries due to the risk of severe hepatotoxicity. Lesinurad was completely withdrawn from the market for commercial reasons and is now unavailable. [22]

Enzyme therapy with pegloticase is indicated for a limited number of patients with severe tophaceous disease who have failed standard therapy. Coadministration with methotrexate significantly increases the proportion of sustained responses and reduces infusion reactions. Glucose-6-phosphate dehydrogenase deficiency must be ruled out before initiation. [23]

Table 3. Xanthine oxidase inhibitors: initiation, titration, key risks

Preparation	Start and titration	Maximum and goals	Special security measures
Allopurinol	Usually 100 mg per day, in chronic kidney disease you can start with 50 mg; increase every 2-4 weeks until the goal is reached	Up to 600-800 mg per day if necessary	Consider HLA-B*58:01 genotyping in high-risk patients. If the result is positive, allopurinol is contraindicated. Monitor skin reactions. [24]
Febuxostat	40 mg per day, if there is no goal, increase to 80 mg	Correction of uric acid levels	In patients with established cardiovascular disease, weigh the risks and benefits. Contraindicated in combination with azathioprine and mercaptopurine. [25]

Special clinical situations and choice of regimen

Chronic kidney disease does not preclude the use of allopurinol. On the contrary, it remains the first-line drug with a low initial dose and slow titration. Probenecid is ineffective and may be unsafe in the presence of a significant decrease in glomerular filtration rate. [26]

For cardiovascular disease, allopurinol is generally preferred. If it is contraindicated or ineffective, febuxostat is considered on an individual basis after a risk discussion, taking into account CARES and FAST data. [27]

If you have a history of urate stones, uricosurics are not recommended. To prevent stone recurrence, a proper fluid intake and, if necessary, alkalinization of urine with citrates under control of urine acidity are important. However, routine alkalinization is not required when prescribing uricosurics and has no proven benefit for most patients with gout. [28]

During an acute attack, urate-lowering therapy should not be discontinued. In fact, current guidelines allow for the initiation of allopurinol immediately during an exacerbation, provided that anti-inflammatory protection is provided. This reduces delays and accelerates the achievement of target values. [29]

Table 4. Quick selection of urate-lowering regimen based on clinical conditions

Situation	Which is preferable?	What to avoid
Chronic kidney disease, moderate to severe	Allopurinol with a low start and titration to the target	Probenecid due to low efficacy and risk
Cardiovascular diseases	Allopurinol as a basic choice	Febuxostat without individual risk assessment
Urate stones	Xanthine oxidase inhibitors, fluid regimen, alkalization as indicated	Uricosurics for nephrolithiasis
Severe tophaceous form, failure of standard therapy	Pegloticase plus methotrexate under observation	Unauthorized discontinuation of therapy during provoked attacks

Drug interactions and safety monitoring

The combination of febuxostat with azathioprine or mercaptopurine is strictly contraindicated. Inhibition of xanthine oxidase sharply increases their concentrations and can lead to severe myelosuppression. This is reflected in the current instructions and confirmed by clinical observations. [30]

Allopurinol and azathioprine used together are only acceptable in specialized situations and with a sharp reduction in the azathioprine dose to approximately a quarter of the original, under frequent blood monitoring. Such regimens should not be used independently. [31]

Colchicine has dangerous interactions with strong CYP3A4 and P-gp inhibitors, especially in patients with renal or hepatic impairment. In such cases, combinations are contraindicated due to the risk of fatal toxicity. Always check concomitant medications, including macrolide antibiotics and some antiviral agents. [32]

Probenecid has numerous pharmacokinetic interactions. It increases the concentrations of many beta-lactam antibiotics and methotrexate, and in patients with impaired renal function, it may lose its uricosuric effect. Probenecid is contraindicated in patients with urate stones. [33]

Table 5. Critical drug interactions in the treatment of gout

Combination	What is the risk?	What to do
Febuxostat plus azathioprine or mercaptopurine	Severe myelosuppression, contraindicated	Do not combine. Find an alternative. [34]
Allopurinol plus azathioprine	A sharp increase in toxicity	Possible only by reducing the dose of azathioprine to approximately 25 percent and frequent blood monitoring in specialized regimens. [35]
Colchicine plus strong CYP3A4 and P-gp inhibitors in renal or hepatic impairment	Risk of fatal toxicity	Avoid combination, look for an alternative. [36]
Probenecid plus beta-lactam antibiotics	Significant increase in antibiotic concentrations	Take this into account when adjusting dosage. Use with caution in cases of reduced renal function. [37]

Uricosurics: place in therapy and limitations

Probenecid is effective in patients with adequate renal function and the absence of urate stones. It is prescribed as an adjunct to allopurinol or as an alternative in cases of intolerance. Adequate fluid intake and monitoring for uricosuria are essential. [38]

Benzbromarone is available in some countries, but its use is restricted due to the risk of severe drug-induced hepatotoxicity. Therefore, with the availability of safe and effective alternatives, its use is becoming less common. [39]

Lesinurad has been withdrawn from production and the market, including in the European Union and the United States, so it is no longer considered an option. If you see references to it, this information is outdated. [40]

For recurrent urate stones, uricosurics are not used. Instead, emphasis is placed on xanthine oxidase inhibitors, fluid intake, and, if necessary, alkalinization of urine with acidity control. [41]

Table 6. Uricosurics: comparison

Preparation	Who is it suitable for?	Key limitations
Probenecid	Preserved renal function, no stones, not reached target on allopurinol	Low efficacy with reduced glomerular filtration rate, multiple interactions
Benzbromarone	If other options are unavailable and under control	Risk of hepatotoxicity, regulatory restrictions in some countries
Lesinurad	Not applicable	The drug has been withdrawn from the market

Biological and enzyme therapy for severe gout

Pegloticase, a uric acid-splitting enzyme, is used in patients with refractory tophaceous gout for whom standard regimens have failed. The drug is administered by infusion according to a strict protocol with premedication and monitoring. Concomitant methotrexate increases treatment compliance and reduces the risk of infusion reactions. [42]

Interleukin-1 inhibitors are used for frequent attacks when standard anti-inflammatory drugs are contraindicated or ineffective. Canacunumab has a corresponding indication in Europe for selected patients. Prescription requires experience and an assessment of the benefit-risk ratio. [43]

These methods do not replace the basic "treat to target" strategy, but rather address the need for complex clinical cases. Proper patient selection and safety monitoring are key to success. [44]

When planning therapy, glucose-6-phosphate dehydrogenase deficiency must be excluded to prevent hemolysis and uric acid levels must be monitored to assess the sustained response. [45]

Table 7. Pegloticase and interleukin 1 inhibitors: when to consider

Situation	What to use	What to control
Refractory tophaceous gout	Pegloticase, preferably with methotrexate	Uric acid levels, infusion reactions, glucose-6-phosphate dehydrogenase deficiency
Frequent attacks with contraindications to standard therapy	Canacunumab in selected patients	Infections, risk profile, efficacy

Practical algorithm for titration and control

Start a xanthine oxidase inhibitor as soon as possible, without delaying it due to an attack. Immediately prescribe anti-inflammatory prophylaxis. Increase the dose every 2-4 weeks until the target is reached, monitoring uric acid monthly. Once the target is reached, monitor at least once a year. This is a simple and reliable path to remission. [46]

If the target level is not achieved with the maximum tolerated dose of allopurinol, add uricosuric if there are no stones and renal function is intact, or switch to febuxostat after assessing cardiovascular risk. In severe cases with tophi and failure of standard therapy, consider pegloticase. [47]

Be mindful of pharmacogenetics. In patients of East Asian and African American descent, HLA-B*58:01 testing before initiating allopurinol is appropriate. A positive result is a strong argument against prescribing. A low start and slow titration reduce the risk of hypersensitivity. [48]

Any unusual skin reactions while taking allopurinol or febuxostat require immediate discontinuation and medical evaluation. Safety is more important than speed of achieving the desired effect. [49]

Table 8. Goals and monitoring of urate-lowering therapy

Parameter	Recommendation
The goal for the majority	Uric acid below 6 mg per deciliter
Target for tophi or frequent attacks	Below 5 mg per deciliter
Titration monitoring frequency	Monthly
Long-term prevention of attacks	Usually 3-6 months, longer if attacks persist