Uricosuric agents are medications that reduce uric acid levels in the blood. They are prescribed to prevent complications from elevated uric acid.
How Uricosuric Agents Work
Uricosuric agents target the kidneys, specifically the renal tubules, to increase uric acid excretion. Normally, the kidneys filter uric acid from the blood, but some of it is reabsorbed back into the bloodstream. These medications inhibit this reabsorption process.
The primary mechanism involves interfering with a protein called urate transporter 1 (URAT1) in the proximal tubules, which is responsible for transporting uric acid back into the blood.
Conditions Treated
Uricosuric agents are prescribed for conditions with excessive uric acid in the blood, known as hyperuricemia. The main condition treated is gout, a painful form of arthritis. Gout occurs when high uric acid levels form monosodium urate crystals that deposit in joints, leading to inflammation and severe pain.
They also treat chronic gouty arthritis. Beyond gout, uricosuric agents are an adjunct treatment for certain bacterial infections. They prolong serum levels of antibiotics like penicillin and cephalosporins by inhibiting kidney secretion, increasing antibiotic availability.
Important Considerations and Side Effects
Patients taking uricosuric agents should be aware of various considerations and potential side effects. Common side effects can include headache, dizziness, nausea, vomiting, and loss of appetite. Other reported reactions include sore gums, skin rash, hair loss, and flushing.
A significant concern with these medications is the increased risk of kidney stone formation, as they boost uric acid excretion in the urine. Staying well-hydrated by drinking plenty of water, potentially enough to produce two liters of urine daily, can help minimize this risk. Serious side effects, such as new or worsening joint pain, severe stomach pain, blood in urine, or signs of liver problems like dark urine or yellowing skin, warrant immediate medical attention.
Uricosuric agents may also interact with other medications, potentially altering the effectiveness or toxicity of either drug. For instance, some uricosurics, such as probenecid (available as Probalan or in combination with colchicine as Col-Probenecid), can increase the blood plasma concentration of other drugs. These medications are generally not suitable for individuals with kidney impairment or a history of high urine concentration of uric acid (hyperuricosuria) due to the increased risk of kidney stones. Regular monitoring of renal function, liver enzymes, and uric acid levels is often recommended.