You have a 54-year-old black patient with gout, diabetes mellitus, hypertension, and chronic kidney disease (CKD). He has an acute gout flare involving his right knee. In the past year he has had four attacks of gout in the ankles and knees, which you treated with intra-articular glucocorticoid injections. He has been on allopurinol (Zyloprim) 200 mg daily, but his last serum urate level was 9.4 mg/dL (reference range 3.0–8.0). His creatinine clearance is 45 mL/minute (reference range 85–125).
In view of his kidney disease, you are concerned about increasing his dose of allopurinol, but also about the need to treat his frequent attacks. How should you manage this patient?
GOUT IS CHALLENGING TO TREAT IN PATIENTS WITH KIDNEY DISEASE
A major challenge in treating patients with gout is to avoid therapeutic interactions with common comorbidities, including hypertension, insulin resistance, coronary artery disease, heart failure, and especially CKD.1
In this paper, we discuss approaches to and controversies in the management of gout and hyperuricemia in patients with CKD. Unfortunately, the evidence from clinical trials to guide treatment decisions is limited; therefore, decisions must often be based on experience and pathophysiologic principles.
GENERAL GOALS OF GOUT THERAPY
Depending on the patient and the stage of the disease, the goals in treating patients with gout are to:
- Terminate acute attacks as promptly and safely as possible
- Prevent recurrences of acute gout attacks
- Prevent or reverse complications resulting from deposition of monosodium urate in the joints, in the kidneys, or at other sites.
These goals are more difficult to achieve in patients with CKD because of the potential complications from many of the available drugs.
TERMINATING ACUTE GOUT FLARES
In patients with acute gout, treatment is aimed at quickly resolving pain and inflammation.
Several types of drugs can terminate acute gout flares. The choice in most situations is colchicine (Colcrys); a nonsteroidal anti-inflammatory drug (NSAID); a corticosteroid; or corticotropin (ACTH).
However, in patients with CKD, there are concerns about using colchicine or NSAIDs, and corticotropin is very expensive; thus, corticosteroids are often used.
Colchicine’s clearance is reduced in CKD
Colchicine is somewhat effective in treating acute gout attacks and probably more effective in preventing attacks.
Due to concerns about inappropriate dosing and reported deaths,2 the intravenous formulation is not available in many countries, including the United States.
After oral administration, colchicine is rapidly absorbed, with a bioavailability of up to 50%. It undergoes metabolism by the liver, and its metabolites are excreted by renal and biliary-intestinal routes. Up to 20% of the active drug is excreted by the kidneys.3
Colchicine’s clearance is significantly reduced in patients with renal or hepatic insufficiency, and the drug may accumulate in cells, with resultant toxicity.4 Colchicine-induced toxicity has been observed when the drug was used for acute treatment, as well as for chronic prophylaxis of gout in patients with CKD; thus, alternative agents for treating acute attacks should be considered.5,6 With prolonged use, reversible colchicine-induced axonal neuropathy, neutropenia, and vacuolar myopathy can develop in patients with CKD.7
In a trial in patients with normal renal function, nearly 100% who received an initial dose of 1 mg followed by 0.5 mg every 2 hours developed diarrhea at a median time of 24 hours.8 Emesis may also occur.
A lower dose of 1.8 mg (two 0.6-mg pills followed by one pill an hour later) was well tolerated but only moderately effective in treating acute gout, causing at least a 50% reduction in pain at 24 hours in only 38% of patients.9 This study does not clarify the dosage to use to completely resolve attacks. Using additional colchicine likely will increase the response rate, but will also increase side effects. Patients with CKD were not included.
Some patients, as shown in the above trial, can abort attacks by taking only one or two colchicine tablets when they feel the first “twinge” of an attack. This approach is likely to be safe in CKD, but it may be of value to only a few patients.
Nonsteroidal anti-inflammatory drugs can worsen chronic kidney disease
NSAIDs in high doses can effectively treat the pain and inflammation of acute gout. Indomethacin (Indocin) 50 mg three times daily has been standard NSAID therapy.
Other nonselective NSAIDs and NSAIDs that selectively inhibit cyclooxygenase 2 (COX-2) are effective, but all can cause acute renal toxicity or worsen CKD.10 Renal side effects include salt and water retention, acute tubular necrosis, acute interstitial nephritis, proteinuria, hypertension, hyperkalemia, and chronic renal injury.11
Even short-term use of high-dose NSAIDs should generally be avoided in patients with preexisting CKD, for whom there is no established safe threshold dose. When NSAIDs (including selective COX-2 inhibitors) are used, renal function should be monitored closely and the duration limited as much as possible.