GOOD: Alternative to antibiotics may prevent recurrent UTIs. “Methenamine is a long-established medication that works by making the urine more acidic and stopping bacterial growth. Studies have shown that it can prevent recurrent UTIs, but it’s not widely used. It’s such an ‘old’ drug, many doctors today do not know about it, said Dr. Karyn Eilber, a urologist at Cedars-Sinai Medical Center in Los Angeles.”