Levofloxacin

Mechanism of Action
L-stereoisomer of parent compound ofloxacin, D-isomer form is inactive
Inhibits DNA gyrase activity, which in turn promotes breakage of DNA strands
Good monotherapy with extended coverage against Pseudomonas spp, as well as excellent activity against pneumococcus 
Pharmacokinetics
Bioavailability: 99%
Peak serum time: 1-2 hr
Excretion: Urine (primarily as unchanged drug)
Contraindications
• Documented hypersensitivity
Adverse Reactions
Nausea, Headache, Diarrhea, Insomnia, Constipation, Dizziness, Dyspepsia, Rash, Vomiting, Chest pain, Dyspnea, Edema, Fatigue, Moniliasis, Pain, Pruritus, Vaginitis
Major Drug Interactions
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Warnings
• Both oral and injectable fluoroquinolones are associated with disabling side effects involving tendons, muscles, joints, nerves and the central nervous system
• Fluoroquinolones have been associated with disabling and potentially irreversible serious adverse reactions that have occurred together including: tendinitis and tendon rupture, peripheral neuropathy, and CNS effects
• Discontinue the drug immediately and avoid use of systemic fluoroquinolones in patients who experience any of these serious adverse reactions
• These side effects can occur hours to weeks after exposure to fluoroquinolones and may potentially be permanent
• May exacerbate muscle weakness in patients with myasthenia gravis, fluoroquinolones should be avoided in patients with known history of myasthenia gravis
• Because the risk of these serious side effects generally outweighs the benefits for patients with acute bacterial sinusitis, acute exacerbation of chronic bronchitis, and uncomplicated UTIs, that fluoroquinolones should be reserved for use in patients with these conditions who have no alternative treatment options
Recommendations for Patient
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Pregnancy Considerations
Levofloxacin has not been shown to increase risk of major birth defects, miscarriage or adverse maternal or fetal outcomes
Breastfeeding Considerations
No information is available on the clinical use of levofloxacin during breastfeeding.

Pregnancy Categories
A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.
B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.
C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.
D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.
X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.
NA: Information not available.