Used primarily in the treatment of urinary tract infections caused by susceptible Gram-negative bacteria, particularly Pseudomonas aeruginosa. It is effective in patients with compromised immune systems or those with chronic urinary tract issues. Due to its stability in acidic environments, it is suitable for oral administration and maintains therapeutic levels in urine, making it especially useful for lower urinary tract infections. Often prescribed when other penicillins are ineffective, especially in cases involving resistant strains.