Allopurinol is a medication prescribed to manage conditions caused by high levels of uric acid in the blood, such as gout. Gout is a painful form of inflammatory arthritis that occurs when excess uric acid forms needle-like crystals in the joints. The drug is also used to prevent certain types of kidney stones and to reduce uric acid levels in patients undergoing specific cancer treatments. Patients often ask if Allopurinol increases the urge or need to urinate.
How Allopurinol Reduces Uric Acid
Allopurinol works by interfering with the body’s production of uric acid. It is classified as a xanthine oxidase inhibitor, meaning it blocks the action of the enzyme xanthine oxidase. This enzyme converts hypoxanthine into xanthine, and then into uric acid, the final waste product of purine metabolism.
By inhibiting xanthine oxidase, Allopurinol reduces the amount of uric acid produced. This lowers the concentration of uric acid in the blood, preventing the formation of urate crystals in the joints and tissues. The drug is metabolized into oxypurinol, an active compound that also inhibits this enzyme and has a longer half-life. This mechanism helps dissolve existing urate crystals and prevent future gout attacks.
Allopurinol and Urination Frequency
Allopurinol is not classified as a diuretic, which are drugs that increase urine output by promoting salt and water excretion by the kidneys. Increased urination, known as polyuria, is not listed among the common side effects of the medication. However, patients may experience increased urination frequency, often an indirect result of the gout treatment plan.
Healthcare providers advise patients with hyperuricemia and gout to increase their daily water intake. Proper hydration helps the kidneys flush uric acid and other byproducts from the body, aiding in preventing kidney stone formation and reducing gout flares. This increased fluid consumption is the most common reason a patient on Allopurinol notices a change in urination frequency.
In rare cases, changes in urinary habits could signal an adverse reaction affecting the kidneys. Symptoms related to kidney function impairment include urinating less often, producing less urine, or having blood in the urine. While the drug increases the excretion of soluble compounds like hypoxanthine and xanthine through the kidneys, this does not typically cause a noticeable increase in overall urine volume.
When to Consult a Healthcare Provider
While increased urination due to higher fluid intake is common, certain urinary changes combined with other symptoms require medical attention.
Kidney-Related Symptoms
Seek consultation if you experience a decrease in the amount of urine produced, or if you notice blood in your urine (which may appear brown or pink). Persistent or painful urination, swelling in the feet or ankles, or foamy urine can indicate a possible kidney issue related to the medication.
Allergic Reaction Symptoms
It is important to watch for signs of allopurinol hypersensitivity syndrome, a rare complication. Symptoms to report include a rash accompanied by fever, flu-like symptoms, or yellowing of the skin or eyes (jaundice). These systemic reactions can affect multiple organs and require evaluation by a healthcare professional.