C. diff Risk


Oral Bioavailability


Approximate Cost



Cystitis Macrobid 100mg PO BID

Contraindicated with CrCl < 60

General Information

Common Usage

Uncomplicated cystitis in females with normal renal function

Adverse Effects

Prolonged use may result in lung and skin toxicity. Caution advised.

Major Interactions

Antacids decrease absorption

Additional Information

Think of this drug as a urinary antiseptic.

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

Avoid in UTI with bloodstream infections or pyelonephritis.


Antimicrobial class: Nitrofuran

Pregnancy category: B [Contraindicated at term]

Average serum half life: 1 hour

Biliary penetration: None

CSF penetration: None

Urine penetration: Therapeutic

Lung penetration: None