moxifloxacin hydrochloride

Action

Selectively inhibits DNA synthesis by disrupting DNA replication and transcription and suppressing protein synthesis, causing bacterial cell death

Availability

Injection (premixed): 400 mg/250-ml bag

Ophthalmic solution: 5% (3 ml in 4-ml bottle)

Tablets: 400 mg

Indications and dosages

➣ Acute bacterial sinusitis

Adults: 400 mg P.O. or I.V. q 24 hours for 10 days

➣ Acute bacterial exacerbation of chronic bronchitis

Adults: 400 mg P.O. or I.V. q 24 hours for 5 days

➣ Community-acquired pneumonia

Adults: 400 mg P.O. or I.V. q 24 hours for 7 to 14 days

➣ Uncomplicated skin and skin-structure infections

Adults: 400 mg P.O. or I.V. q 24 hours for 7 days

➣ Bacterial conjunctivitis

Adults: Instill one drop of Vigamox ophthalmic solution into affected eye t.i.d. for 7 days or one drop of Moxeza ophthalmic solution into affected eye b.i.d. for 7 days.

Contraindications

• Hypersensitivity to drug, its components, or other fluoroquinolones

Precautions

Use cautiously in:

• known or suspected CNS disorders that may predispose to seizures or lower seizure threshold, peripheral neuropathy, diarrhea, renal impairment, cirrhosis, bradycardia, acute myocardial ischemia, dialysis

• prolonged QTc interval, hypokalemia, and drugs that prolong QT interval

• history of myasthenia gravis (avoid use)

• elderly patients

• pregnant or breastfeeding patients (safety not established except in post-exposure inhalation anthrax)

• children younger than age 18 (except in post-exposure inhalation anthrax)

• children younger than age 4 months (Moxeza ophthalmic use) or age 1 (Vigamox ophthalmic use).

Administration

• Give premixed I.V. dose over 60 minutes. Avoid bolus or rapid infusion.

• Don't mix with other drugs in same I.V. line.

• Know that although milk or yogurt may impair absorption of P.O. moxifloxacin, drug may be given with other calcium products.

Adverse reactions

CNS: dizziness, drowsiness, headache, confusion, light-headedness, insomnia, agitation, hallucinations, acute psychoses, tremor, seizures

CV: hypertension, vasodilation, tachycardia, prolonged QT interval, arrhythmias

EENT: conjunctivitis; decreased visual acuity; keratitis; eye dryness, discomfort, pain, pruritus, and hyperemia; subconjunctival hemorrhage; tearing; otitis media; pharyngitis; rhinitis (all with ophthalmic solution)

GI: nausea, diarrhea, abdominal pain, pseudomembranous colitis

GU: vaginitis

Hematologic: eosinophilia, thrombocytopenia, leukopenia

Musculoskeletal: joint pain, tendinitis, tendon rupture

Respiratory: increased cough (with ophthalmic solution)

Skin: rash, photosensitivity, phototoxicity, Stevens-Johnson syndrome

Other: altered taste (with ophthalmic solution), phlebitis at I.V. site, superinfection, fever, exacerbation of myasthenia gravis, hypersensitivity reactions including anaphylaxis

Interactions

Drug-drug. Amiodarone, bepridil, disopyramide, erythromycin, pentamidine, phenothiazines, pimozide, procainamide, quinidine, sotalol, tricyclic antidepressants: increased risk of serious adverse cardiovascular reactions

Antacids, bismuth subsalicylate, iron salts, sucralfate, zinc salts: decreased moxifloxacin absorption

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

Theophylline: increased theophylline blood level and possible toxicity

Warfarin and its derivatives: enhanced anticoagulant effect

Drug-diagnostic tests. Alanine aminotransferase, alkaline phosphatase, aspartate aminotransferase, bilirubin, lactate dehydrogenase, platelets: increased levels

Drug-food. Concurrent tube feedings, milk, yogurt: impaired absorption of P.O. moxifloxacin

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

Fennel: decreased moxifloxacin absorption

Drug-behaviors. Sun exposure: phototoxicity

Patient monitoring

See Watch for hypersensitivity reaction (such as anaphylaxis) and other allergic reactions, which may occur after initial dose. Discontinue drug at first sign of rash, jaundice, or other signs or symptoms of hypersensitivity.

• Monitor cardiovascular and neurologic status closely.

See Stay alert for tendinitis and Achilles tendon rupture. Discontinue drug if tendon pain or inflammation occurs.

• Monitor CBC and liver function tests.

• Assess GI status. Report signs or symptoms of pseudomembranous colitis. Be aware that if pseudomembranous colitis is suspected or confirmed, ongoing antibiotic use not directed against Clostridium difficile may need to be discontinued.

• Watch closely for superinfection.

• Discontinue drug if peripheral neuropathy or phototoxicity occurs.

• Closely monitor prothrombin time, International Normalized Ratio, or other suitable anticoagulation tests if drug is given concomitantly with warfarin or its derivatives.

Patient teaching

• Advise patient to take tablets once a day with or without food, 4 hours before or 8 hours after antacids, multivitamins, sucralfate, or preparations containing aluminum, magnesium, iron, or zinc.

See Tell patient drug may cause serious allergic reactions even several days after therapy begins. Advise him to stop taking drug and report these reactions immediately.

See Urge patient to stop taking drug and promptly report tendon pain, diarrhea with blood or pus, and signs and symptoms of superinfection.

• Teach patient how to use eye drops. Caution him to avoid touching applicator tip to eye, finger, or other object.

• Instruct patient being treated for bacterial conjunctivitis not to wear contact lenses.

• Caution patient to avoid driving and other hazardous activities until he knows how drug affects concentration and alertness.

• 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.