Hussain and Bray (2019) noted that urethral bulking agents (UBAs) to treat SUI was first described in the 1930s, when paraffin was used to increase urethral resistance. Since then, several agents have been introduced to the market, with varying degrees of safety, efficacy, and durability. The agents currently available include calcium hydroxyl apatite (Coaptite), carbon coated zirconium (Durasphere; polydimethylsiloxane elastomer (Macroplastique); and polyacrylamide hydrogel (Bulkamid). The latest product, PDMS-U (Urolastic ) is a silicone gel that polymerizes when injected. The short-term efficacy of UBAs are generally encouraging; however, longer follow-up results show the success rates are reduced and many women will require a repeat treatment.