This page about uricosuric drugs (urosuric drugs) was last reviewed, or updated, on 11 May 2013.
Probenecid, sulfinpyrazone and benzbromarone are classed as uricosuric (aka urosuric). They encourage the body to excrete uric acid in the urine by preventing the kidneys from re-absorbing it into the blood, so there's less in the blood. They are a long term gout treatment because insufficient uric acid excretion is for many people the cause of hyperuricemia. When there's less in the blood, gout's MSU crystals are less likely to form, and existing crystals are more likely to dissolve.
Uricosuric drugs are worth knowing about because, I suspect, it is now medically fashionable to treat excess uric acid with the other class - those that reduce uric acid production. There's then less to excrete. But most people have gout because they don't expel uric acid well, for one reason or another, and these drugs tackle that directly.
BRAND NAMES: BENCID, BENECID, BENEMID, PARBENEM, PROBALAN, BENURYL, PROBECID, PRO-CID, BENEMIDE, PROBEN.
Probenecid is the second oldest still-current gout drug, (after colchicine), having been used in gout treatment since at least 1951.
It works also to head off another danger of excess uric acid, which is the formation of uric acid kidney stones. These stones may also form in the ureters and the bladder.
Once started, probenecid is a long term gout treatment which doctors will want to continue. Albeit at a lower dose than in initial treatment, as long as this dose maintains uric acid below 6.0 mg/dL men, bit less in women.
In the early stages of treatment, a risk is that uricosuric drugs may increase the frequency and severity of gout attacks. So colchicine may be prescribed with probenecid (or the others, below) to help prevent the next gout attack. But eventually (probably 6 months to 2 years) attacks cease for most sufferers.
You need to drink lots of water on a course of probenecid, perhaps supplemented with an alkalizing (alkalising) agent such as potassium citrate, (see below), if your doctor agrees. Drinking water is always essential in both drug medication and natural remedy gout treatment, and is worth repeating again because use of probenecid can lead to the formation of MSU gout crystals and kidney stones.
If a gout attack occurs and you are already taking it, you continue to do so. But don't start taking it during a gout attack.
It cannot be taken by gout patients with kidney stones, or a kidney disease, or a with a risk of developing kidney disease from other causes. Your doctor should do a blood creatinine test to find out how well your kidneys are working before starting you on it. If they aren't working well enough it won't work, but allopurinol and febuxostat (which both lower uric acid production and don't act on the kidneys) probably will be prescribed.
If you take probenecid your doctor may also consider whether you need to make your urine less acidic and more alkaline (higher urine pH). Acidic urine can be a part cause of uric acid kidney stones. Keeping the urine diluted and alkaline (a higher pH number) helps to prevent this.
And doing it by diet can be read here. Although this study was not conducted on gout sufferers, it was successful.
Dosage 250-500mg twice daily. Lower initially, half a 500 mg tablet. Dosage may be less if your drink plenty of water. Low dose aspirin should probably not be taken with it. Low dose aspirin may stop it working and it is feared as a cause of gout. Discuss this point with your doctor. If there's no recurrent gout attack in six months the dosage will probably be reduced. Keep checking for lowered uric acid levels.
Possible probenecid side effects It is usually well tolerated, but side effects include – headaches, nausea, vomiting, skin rashes, gout crystal kidney stones, bone marrow depression, and appetite loss. It may reduce the excretion of other drugs from the body.
SOME BRAND NAMES: ANTURANE, ANTURAN.
Sulfinpyrazone, also spelt sulphinpyrazone, is another uricosuric drug for gout. It too works by encouraging uric acid excretion. It may be used instead of probenecid because its side effects are different and it is thought to be stronger and sometimes more effective than probenecid. The other usual caveat of these uricosuric medications applies – if a gout attack occurs and you're already taking them, continue to do so.
But don't start taking sulfinpyrazone during a gout attack. Drink lots of water to help avoid the creation of MSU gout crystals as kidney stones – remember that sudden changes of uric acid levels are a gout trigger. See the What to drink? page for why.
Sulfinpyrazone is said to work better when the body is more alkaline (higher pH levels). As with probenecid, people with kidney disorders, or a risk for them from other causes, should not take it.
Dosage Tablets or capsules. 50 - 200mg initially twice daily, gradually up to up to 200 – 400mg twice daily. May be less if you drink lots of water. Low dose aspirin should probably not be taken with sulfinpyrazone. It may stop it working. Discuss this point with your doctor.
Possible side effects include breathing difficulties; sore throat; swollen glands; bleeding and bruising; fevers; bone marrow disorder; ulcers.
Sulfinpyrazone is not available in the U.S.
BRAND NAMES: DESURIC, ALLOBENZ, BENZMARON, BENRONE, BENZRO, BROMANONE, GOUTIL, NARCARICIN.
Benzbromarone, the third of the uricosuric drugs, has been an under-excretor drug medication for about 25 tears. In some studies it has achieved excellent results - a uric acid fall of around 5.0 mg/dL, which is a very good reduction.
Benzbromarone is available in some countries (e.g. Great Britain, New Zealand, Italy, Japan, China, Taiwan and Germany). But in others it was withdrawn (e.g. the U.S., France, some other European countries), mainly because of concerns that it can harm the liver. Ask your doctor whether it is available in your country. S/he may order liver tests for you first.
Vitamin C is thought to lower uric acid by having a uricosuric (urosuric) effect too. Read a meta-analysis (study of studies) of Vitamin C and uric acid studies.