Some of the selenium oxyhalides, such as selenium oxyfluoride (SeOF2) and selenium oxychloride (SeOCl2) have been used as specialty solvents. Selenides
Analogous to the behavior of other chalcogens, selenium forms hydrogen selenide, H2Se. It is a strongly odiferous, toxic, and colorless gas. It is more acidic than H2S. In solution it ionizes to HSe−. The selenide dianion Se2− forms a variety of compounds, including the minerals from which selenium is obtained commercially. Illustrative selenides include mercury selenide (HgSe), lead selenide (PbSe), zinc selenide (ZnSe), and copper indium gallium diselenide (Cu(Ga,In)Se2). These materials are semiconductors.
They are often used in combination with either an NSAID or colchicine for the first three to six months.While it has been recommended that urate-lowering measures should be increased until serum uric acid levels are below 300–360 µmol/L (5.0–6.0 mg/dl), there is little evidence to support this practice over simple putting people on a standard dose of allopurinol. If these medications are in chronic use at the time of an attack, it is recommended that they be continued. Levels that cannot be brought below 6.0 mg/dl while attacks continue indicates refractory gout.While historically it is not recommended to start allopurinol during an acute attack of gout, this practice appears acceptable. Allopurinol blocks uric acid production, and is the most commonly used agent. Long term therapy is safe and well-tolerated and can be used in people with renal impairment or urate stones, although hypersensitivity occurs in a small number of individuals. The HLA-B*58:01 allele of the human leukocyte antigen B (HLA-B) is strongly associated with severe cutaneous adverse reactions during treatment with allopurinol and is most common among Asian subpopulations, notably those of Korean, Han-Chinese, or Thai descent.Febuxostat is only recommended in those who cannot tolerate allopurinol. There are concerns about more deaths with febuxostat compared to allopurinol. Febuxostat may also increase the rate of gout flares during early treatment. However, there is tentative evidence that febuxostat may bring down urate levels more than allopurinol.Probenecid appears to be less effective than allopurinol and is a second line agent.