Pyelonephritis can be prevented secondarily in some cases by giving long term prophylactic antibiotics. Correction of a structural defect that leads to the initial episode of pyelonephritis may also be helpful in eliminating chances of recurrence of pyelonephritis.

• If no structural or functional abnormality is identified, some studies suggest long-term preventative (prophylactic) treatment with antibiotics, either daily or after sexual intercourse.^[1]
• In children at risk of recurrent UTIs, the evidence is inconclusive as to whether long-term prophylactic antibiotics are of use.^[2]
• Ingestion of cranberry juice has been studied as a prophylactic measure; while studies are heterogeneous, many suggest a benefit.^[3]

• Prophylaxis is required in individuals having two or more episodes of urinary tract infections in 6 months or three or more episodes in 12 months period.^[4][5]
• Prophylactic therapy using antimicrobial agents may be considered as either continuously or postcoital prophylaxis for 6 to 12 months.
• The following regimens may be used as single doses prior to sexual activity.^[6]

• Prophylactic Therapy:

• Preferred regimen (1): Fosfomycin tromethamine 3 g PO in a single dose
• Preferred regimen (2): Nitrofurantoin monohydrate/macrocrystals 100 mg PO in a single dose
• Preferred regimen (3): Trimethoprim-Sulfamethoxazole 160/800 mg PO double-strength tablet bid in a single dose
• Preferred regimen (4): Trimethoprim 100 mg PO bid in a single dose
• Alternative regimen (1): Ciprofloxacin 250 mg PO bid in a single dose
• Alternative regimen (2): Levofloxacin 250 mg PO qd in a single dose
• Alternative regimen (3): Norfloxacin 400 mg PO bid in a single dose
• Alternative regimen (4): Gatifloxacin 200 mg PO qd in a single dose

• Post-Coital Ciprofloxacin has been found to be similar in effect to daily Ciprofloxacin.^[7]
• Nitrofurantoin and Fosfomycin effective for use as long term prophylaxis.^[8][9]