Sulfalene (INN, USAN) or sulfametopyrazine (BAN) is a long-acting sulfonamide antibacterial used for the treatment of chronic bronchitis, urinary tract infections and malaria. As of 2014 there were only two countries in which it is currently still marketed: Thailand and Ireland. It was discovered by researchers at Farmitalia and first published in 1960 and was marketed as Kelfizina.