levofloxacin

Action

Inhibits the enzyme DNA gyrase in susceptible gram-negative and gram-positive aerobic and anaerobic bacteria, interfering with bacterial DNA synthesis

Availability

Ophthalmic solution: Quixin-0.5% (5 mg/ml), Iquix-1.5%

Premixed solution for injection: 250 mg/50 ml, 500 mg/100 ml, 750 mg/150 ml

Solution for injection (concentrated): 500 mg/20 ml

Tablets: 250 mg, 500 mg, 750 mg

Indications and dosages

➣ Acute bacterial exacerbation of chronic bronchitis

Adults: 500 mg I.V. or P.O. q 24 hours for 7 days

➣ Community-acquired pneumonia

Adults: 500 mg I.V. or P.O. q 24 hours for 7 to 14 days, or 750 mg I.V. or P.O. q 24 hours for 5 days

➣ Nosocomial pneumonia caused by methicillin-susceptible strains of Staphylococcus aureus, Pseudomonas aeruginosa, Serratia marcescens, Escherichia coli, Klebsiella pneumoniae, Haemophilus influenzae, or Streptococcus pneumoniae; complicated skin and skin-structure infections

Adults: 750 mg I.V. or P.O. q 24 hours for 7 to 14 days

➣ Acute bacterial sinusitis caused by S. pneumoniae, H. influenzae, or Moraxella catarrhalis

Adults: 500 mg I.V. or P.O. q 24 hours for 10 to 14 days or 750 mg P.O. or I.V. q 24 hours for 5 days

➣ Uncomplicated skin and skin-structure infections

Adults: 500 mg I.V. or P.O. q 24 hours for 7 to 10 days

➣ Complicated urinary tract infections; acute pyelonephritis caused by E. coli

Adults: 250 mg I.V. or P.O. q 24 hours for 10 days or 750 mg P.O. or I.V. q 24 hours for 5 days

➣ Uncomplicated urinary tract infections

Adults: 250 mg I.V. or P.O. q 24 hours for 3 days

➣ Chronic bacterial prostatitis

Adults: 500 mg I.V. or P.O. q 24 hours for 28 days.

➣ Conjunctivitis

Adults and children ages 1 and older: One or two drops of 0.5% ophthalmic solution into affected eye q 2 hours while awake on days 1 and 2 (up to eight times daily); then one or two drops q 4 hours while awake on days 3 through 7 (up to four times daily)

➣ Corneal ulcers

Adults and children ages 6 and older: On days 1 to 3, one or two drops of 1.5% ophthalmic solution instilled into affected eye(s) q 30 minutes to 1 hour while awake and q 4 to 6 hours after retiring; thereafter, one or two drops q 1 to 4 hours while awake until treatment completion

➣ Inhalational anthrax (postexposure)

Adults and children ages 6 months and older weighing more than 50 kg (110 lb): 500 mg P.O. or I.V. q 24 hours for 60 days

Children ages 6 months and older weighing less than 50 kg (110 lb): 8 mg/kg P.O. or I.V., not to exceed 250 mg/dose q 12 hours for 60 days

Dosage adjustment

• Renal impairment

Contraindications

• Hypersensitivity to drug, its components, or other quinolones

Precautions

Use cautiously in:

• bradycardia, acute myocardial ischemia, prolonged QTc interval, cirrhosis, renal impairment, underlying CNS disease, uncorrected hypocalcemia

• elderly patients

• pregnant or breastfeeding patients

• children younger than age 18 (except in ophthalmic use).

Administration

• Be aware that oral and I.V. dosages are identical.

• Give parenteral form by I.V. route only. Drug isn't for I.M., subcutaneous, intrathecal, or intraperitoneal use.

• To prepare I.V. infusion, use compatible solution, such as 0.9% sodium chloride injection, dextrose 5% and 0.9% sodium chloride injection, dextrose 5% in water, or dextrose 5% in lactated Ringer's solution.

• Infuse over 60 to 90 minutes, depending on dosage. Don't infuse with other drugs.

☞ Avoid rapid or bolus I.V. administration, because this may cause severe hypotension

• Flush I.V. line before and after infusion.

• Give oral doses 2 hours before or after sucralfate, iron, antacids containing magnesium or aluminum, or multivitamins with zinc.

• Give oral form without regard to food, but don't give with milk or yogurt alone.

• Be aware that the two ophthalmic preparations have different indications.

Adverse reactions

CNS: dizziness, headache, insomnia, seizures

CV: chest pain, palpitations, hypotension

EENT: photophobia, sinusitis, pharyngitis

GI: nausea, vomiting, diarrhea, constipation, abdominal pain, dyspepsia, flatulence, pseudomembranous colitis

GU: vaginitis

Hematologic: lymphocytopenia

Metabolic: hyperglycemia, hypoglycemia

Musculoskeletal: back pain, tendon rupture, tendinitis

Skin: photosensitivity

Other: altered taste, reaction and pain at I.V. site, hypersensitivity reactions including Stevens-Johnson syndrome

Interactions

Drug-drug. Antacids containing aluminum or magnesium, didanosine (tablets), iron salts, sucralfate, zinc salts: decreased levofloxacin absorption

Cimetidine: interference with levofloxacin elimination

Nonsteroidal anti-inflammatory drugs: increased risk of CNS stimulation and seizures

Drug-diagnostic tests. Glucose: increased or decreased level

Lymphocytes: decreased count

EEG: abnormal findings

Drug-food. Concurrent tube feedings, milk, yogurt: impaired levofloxacin absorption

Drug-herbs. Dong quai, St. John's wort: phototoxicity

Fennel: decreased levofloxacin absorption

Drug-behaviors. Sun exposure: phototoxicity

Patient monitoring

• Check vital signs, especially blood pressure. Too-rapid infusion can cause hypotension.

• Closely monitor patients with renal insufficiency.

• Monitor blood glucose level closely in diabetic patients.

☞ Assess for severe diarrhea, which may indicate pseudomembranous colitis.

☞ Watch for hypersensitivity reaction. Discontinue drug immediately if rash or other signs or symptoms occur.

☞ Watch for signs and symptoms of tendinitis or tendon rupture.

Patient teaching

☞ Tell patient to stop taking drug and contact prescriber if he experiences signs or symptoms of hypersensitivity reaction (rash, hives, or other skin reactions) or severe diarrhea (which may indicate pseudomembranous colitis).

☞ Instruct patient to stop taking drug and notify prescriber immediately if tendon pain, swelling, or inflammation occurs.

• Instruct patient not to take with milk, yogurt, multivitamins containing zinc or iron, or antacids containing aluminum or magnesium.

• Teach patient proper use of eye drops. Tell him to avoid touching applicator tip to eye, finger, or any other object.

• Caution patient to avoid driving and other activities that require mental alertness until CNS effects of drug are known.

• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs, tests, foods, herbs, and behaviors mentioned above.