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Nitrofurantoin

Chemical Structure / Formula of Nitrofurantoin

  • Formula: C8H6N4O5

  • Structure: A nitrofuran derivative with a hydantoin ring.

Chemical Structure of Nitrofurantoin

Mechanism of Action

  • Prodrug that is reduced by bacterial nitroreductases to reactive metabolites.

  • These metabolites damage bacterial DNA, ribosomes, and proteins, leading to cell death.

Uses

  • Uncomplicated UTIs (first-line therapy for cystitis).

  • Effective against E. coli, Enterococcus, Staphylococcus saprophyticus.

  • Not effective for pyelonephritis or systemic infections (low tissue penetration).

Side Effects

  • GI upset (nausea, vomiting, diarrhea).

  • Pulmonary toxicity (acute and chronic pneumonitis, fibrosis).

  • Hepatotoxicity (rare but serious).

  • Hemolysis in G6PD-deficient patients.

Structure-Activity Relationship (SAR) of Nitrofurantoin

Structural Feature

SAR Insight

Nitrofuran ring

Essential for antimicrobial activity; nitro group is reduced by bacterial enzymes to reactive intermediates.

Side chain with hydantoin (imidazolidinedione)

Important for solubility, absorption, and activity.

Electron-withdrawing nitro group

Critical for redox cycling and formation of reactive species.

Modifications on furan ring

Usually reduce activity or bioavailability.

Increased lipophilicity

May enhance bacterial uptake but can increase toxicity.

Synthesis of Nitrofurantoin

Synthesis of Nitrofurantoin

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