Levofloxacin
Common Brand Names: Levaquin
Therapeutic Class: A fluoroquinolone antibiotic
Common Injectable Dosage Forms:
Injection (concentrate): 25 mg/mL in 20 mL and 30 mL vials
Injection (premix): 5 mg/mL in 50 mL, 100 mL, and 150 mL containers
Dosage Ranges:
For the treatment of the following infections caused by susceptible strains:
Acute bacterial exacerbations of chronic bronchitis: 500 mg every 24 hours for 7 days.
Community-acquired pneumonia: 500 mg every 24 hours for 7-14 days or 750 mg every 24 hours for 5 days.
Acute maxillary sinusitis: 500 mg every 24 hours for 10-14 days.
Uncomplicated skin and skin structure infections: 500 mg every 24 hours for 7-14 days.
Complicated skin and skin structure infections: 750 mg every 24 hours for 10 days.
Complicated urinary tract infections: 250 mg every 24 hours for 10 days.
Acute pyelonephritis: 250 mg every 24 hours for 10 days.
Uncomplicated urinary tract infections: 250 mg every 24 hours for 3 days.
Nosocomial pneumonia: 750 mg every 24 hours for 7-14 days.
Chronic bacterial prostatitis: 500 mg every 24 hours for 28 days.
Administration and Stability: Levaquin injection should only be administered by intravenous infusion. It is not for intramuscular, intrathecal, intraperitoneal, or subcutaneous administration. It should be infused intravenously slowly over a period of not less than 60 or 90 minutes, depending on the dosage. The single-use vials must be diluted to a final concentration of 5 mg/mL in a compatible solution. Diluted to this concentration, Levaquin is stable for 72 hours at or below 25°C (77°F), for 14 days when stored under refrigeration at 5°C (41°F), and for 6 months when stored frozen at –20°C (-4°F). Frozen solutions should be thawed at room temperature or in a refrigerator only and cannot be refrozen. pH 3.8-5.8
Pharmacology/Pharmacokinetics: Levofloxacin is a fluoroquinolone which exerts its antibacterial actions by preventing the synthesis of bacterial DNA through inhibition of the enzyme DNA gyrase. Levofloxacin has a wide range of activity against Gram-negative and Gram-positive bacteria, including H. influenzae, M. catarrhalis, S. pneumoniae, S. aureus, H. parainfluenzae, S. pyogenes, E. coli, E. cloacae, C. pneumoniae, M. pneumoniae, L. pneumophila, K. pneumoniae, P. aeruginosa, E. faecalis, and P. mirabilis. 24-38% is serum protein bound. 87% is excreted unchanged in the urine. The remaining is metabolized to inactive metabolites. Serum half-life is 6-8 hours.
Drug and Lab Interactions: Do not administer with or use the same intravenous line with any solution containing multivalent cations, e.g., magnesium. Nonsteroidal anti-inflammatory agents may lower seizure thresholds and predispose patients to convulsive seizures when taking levofloxacin. Other quinolones have been shown to have mild drug interactions with warfarin and theophylline therefore appropriate monitoring is recommended. Disturbances of blood glucose has occurred in patients taking quinolones and antidiabetic agents. May have additive effects with QUINIDINE, PROCAINAMIDE, AMIODARONE, SOTALOL, and other Class Ia or Class III antiarrhythmics.
Contraindications/Precautions: Contraindicated in patients with a hypersensitivity to quinolones. Use with caution in patients with known or suspected CNS disorders, especially those which predispose to seizures. Convulsions, increased intracranial pressure, and psychosis have been reported in patients receiving quinolones. Quinolones have been associated with prolongation of the QT interval and should be avoided in patients with uncorrected hypokalemia and patients receiving Class Ia (quinidine, procainamide) and Class III (amiodarone, sotalol) antiarrhythmic agents. Quinolones have been reported to cause serious and sometimes fatal hypersensitivity reactions – therapy should be discontinued at the first sign of a skin rash or other allergic reaction. Quinolones have been shown to cause ruptures of the shoulder, hand, and Achilles' tendons. Levaquin should be discontinued if the patient experiences pain, inflammation, or rupture of a tendon. Use with caution in patients with impaired liver function. Periodic liver function tests should be performed during prolonged (I.e., ≥21 days) therapy. Use with caution in nursing mothers. Not indicated for treatment for treatment of infections in patients under the age of 18 years. Pregnancy Category C.
Monitoring Parameters: Renal and hepatic function, ophthalmic function, hematopoietic function, WBC, and signs of infection
Adverse Effects: Nausea (7%), diarrhea (5%), headache (5%), constipation (3%), and taste perversion (1%).
Common Clinical Applications:
A broad-spectrum antibiotic useful against a wide range of Gram-negative and Gram-positive microorganisms.
