C. diff Risk


Oral Bioavailability


Approximate Cost


Uncomplicated cystitis
Macrobid 100mg PO BID

Caution - not indicated for treatment of pyelonephritis

General Information

Common Usage

Uncomplicated cystitis in females with normal renal function

Adverse Effects

Interstitial pneumonitis and fibrosis especially with prolonged use.

Peripheral neuropathy.

Major Interactions

Antacids decrease absorption

Additional Information

Think of this drug as a urinary antiseptic.

Caution - not indicated for treatment of pyelonephritis

Not recommended in males due to inadequate tissue penetration, especially with possible occult prostatitis.


Antimicrobial class: Nitrofuran

Pregnancy category: B

Average serum half life: 1 hour

Biliary penetration: None

CSF penetration: None

Lung penetration: None

Urine penetration: Therapeutic