Inclusion Criteria:

• A female must be non-lactating, non-breastfeeding and at no risk for pregnancy.
• A condition of general good health, based upon the results of a medical history, physical examination, and laboratory profile.

• Subject must have a diagnosis of acute bacterial sinusitis. The diagnosis must be based on the following:

  • a sinus radiograph or CT scan performed within 48 hours pre-treatment
  • with evidence of maxillary opacification or air/fluid levels
• Purulent discharge from the nose

• At least one of the following clinical signs and symptoms of acute bacterial sinusitis

  • Lasting for more than 7 days prior to and no longer than 21 days before Evaluation 1: facial pain over the sinus or facial pressure over the sinus or facial tightness over the sinus or facial swelling or toothache.
• Subject must be a suitable candidate for oral antimicrobial therapy and is able to swallow capsules intact.

Exclusion Criteria:

• Subjects who have: chronic sinusitis (signs and symptoms lasting greater than 28 days prior to Evaluation 1)
• Significant anatomical abnormalities of the sinuses
• Any other infection or condition which necessitates use of a concomitant systemic antimicrobial.
• History of any hypersensitivity or allergic reactions to penicillins, cephalosporins (including cefdinir), or quinolones (including levofloxacin).
• Subject who has taken: a systemic antibiotic within 14 days before study drug administration; a long acting injectable antibiotic (e.g., penicillin G benzathine) within 30 days before study drug administration.
• Known significant renal or hepatic impairment.
• Evidence of uncontrolled clinically significant cardiovascular, pulmonary, metabolic, gastrointestinal, neurological or endocrine disease, malignancy, or other abnormality (other than the disease being studied).
• Investigator considers the subject unsuitable for cefdinir or levofloxacin therapy, for any reason.
• Previous enrollment in this study.
• Any underlying condition or disease state that would interfere with the completion of the study procedures and evaluations or absorption of study drug.
• Subject who is currently receiving or who is likely to require any of the following medications during the period between Evaluation 1 (initial presentation to office/clinic) and Evaluation 3 (or within 48 hours after the last dose of study drug): Concomitant theophylline or any theophylline analog, unless plasma levels of these drugs can be adequately monitored during the study; Warfarin and probenecid.
• Immunocompromised subjects.
• Subject who requires parenteral antibiotic therapy for this infection or who has any other infection or condition, that necessitates use of a concomitant systemic antibiotic.
• Subjects receiving antacids containing magnesium, or aluminum, as well as sucralfate, metal cations such as iron, and multivitamin preparations with zinc within 2 hours before or after dosing with study drug.
• Subjects with a known or suspected central nervous system disorder that may predispose the subject to seizures or lower the seizure threshold.