methenamine

Methenamine is a small molecule urinary tract antiseptic and antibacterial drug primarily used for the prophylaxis and long-term treatment of frequently recurring urinary tract infections (UTIs)[1][2][3][4]. It is administered orally as either the hippurate or mandelate salt. Methenamine itself has no direct antibacterial activity in alkaline environments; its mechanism of action relies on hydrolysis in acidic urine (pH <6), where it decomposes to release formaldehyde—a highly bactericidal agent that denatures bacterial proteins and nucleic acids[1][5][6][8]. The acid salt component (e.g., hippuric acid) helps maintain an acidic urine environment to optimize this effect. Methenamine is effective against a broad range of urinary pathogens but may be less effective against urea-splitting bacteria such as Proteus or Pseudomonas species that can alkalinize urine[6]. Microbial resistance to formaldehyde does not develop. Methenamine is approved for use in both adults and children for prevention and treatment of UTIs requiring long-term therapy[1][4].

Brand names

HiprexMandelamineUrexHyophenPhosphasalUrelleUribelUrimar Reformulated Oct 2013Urin DSUrogesic Blue Reformulated Apr 2012Ustell

Other names

hexamethylenetetramine