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Pronunciation
(gat i FLOKS a sin)
U.S. Brand Names
Generic Available
No
Canadian Brand Names
Pharmacologic Category
Pharmacologic Category Synonyms
Use: Labeled Indications
Treatment of bacterial conjunctivitis
Pregnancy Risk Factor
C
Pregnancy Considerations
Reports of arthropathy (observed in immature animals and reported rarely in humans) have limited the use of fluoroquinolones during pregnancy. Gatifloxacin has been show to be fetotoxic in animal studies. There are no adequate and well-controlled studies in pregnant women. Based on limited data, quinolones are not expected to be a major human teratogen. Although quinolone antibiotics should not be used as first-line agents during pregnancy, when considering treatment for life-threatening infection and/or prolonged duration of therapy, the potential risk to the fetus must be balanced against the severity of the potential illness.
Lactation
Excretion in breast milk unknown/use caution
Breast-Feeding Considerations
Other quinolones are known to be excreted in breast milk. The manufacturer recommends using caution if gatifloxacin is administered while nursing.
Contraindications
Hypersensitivity to gatifloxacin, other quinolone antibiotics, or any component of the formulation
Warnings/Precautions
Concerns related to adverse effects:
• Hypersensitivity reactions: Severe hypersensitivity reactions, including anaphylaxis, have occurred with systemic quinolone therapy. The spectrum of these reactions can vary widely; reactions may present as typical allergic symptoms (eg, itching, urticaria, rash, edema) after a single dose, or may manifest as severe idiosyncratic dermatologic (eg, Stevens-Johnson, toxic epidermal necrolysis), vascular (eg, vasculitis), pulmonary (eg, pneumonitis), renal (eg, nephritis), hepatic (eg, hepatic failure or necrosis), and/or hematologic (eg, anemia, cytopenias) events, usually after multiple doses. Prompt discontinuation of drug should occur if skin rash or other symptoms arise.
• Superinfection: Prolonged use may result in fungal or bacterial superinfection.
Special populations:
• Contact lens wearers: Contact lenses should not be worn during treatment of ophthalmic infections.
• Pediatrics: Safety and efficacy have not been established in children <1 year of age.
Dosage form specific issues:
• Ophthalmic solution: Do not inject ophthalmic solution subconjunctivally or introduce directly into the anterior chamber of the eye.
Adverse Reactions
5% to 10%: Ocular: Conjunctival irritation, keratitis, lacrimation increased, papillary conjunctivitis
1% to 4%:
Central nervous system: Headache
Gastrointestinal: Taste disturbance
Ocular: Chemosis, conjunctival hemorrhage, discharge, dry eye, edema, irritation, pain, visual acuity decreased
Drug Interactions
Alfuzosin: May enhance the QTc-prolonging effect of QTc-Prolonging Agents. Risk C: Monitor therapy
Antacids: May decrease the absorption of Quinolone Antibiotics. Of concern only with oral administration of quinolones. Exceptions: Sodium Bicarbonate. Risk D: Consider therapy modification
Artemether: May enhance the QTc-prolonging effect of QTc-Prolonging Agents. Risk X: Avoid combination
BCG: Antibiotics may diminish the therapeutic effect of BCG. Risk X: Avoid combination
Calcium Salts: May decrease the absorption of Quinolone Antibiotics. Of concern only with oral administration of both agents. Exceptions: Calcium Chloride. Risk D: Consider therapy modification
Chloroquine: May enhance the QTc-prolonging effect of QTc-Prolonging Agents. Risk C: Monitor therapy
Ciprofloxacin: May enhance the QTc-prolonging effect of QTc-Prolonging Agents. Risk C: Monitor therapy
Ciprofloxacin, Systemic: May enhance the QTc-prolonging effect of QTc-Prolonging Agents. Risk C: Monitor therapy
Corticosteroids (Systemic): Quinolone Antibiotics may enhance the adverse/toxic effect of Corticosteroids (Systemic). Risk of tendon-related side effects, including tendonitis and rupture, may be enhanced. Risk C: Monitor therapy
Didanosine: May decrease the absorption of Quinolone Antibiotics. Of concern only with oral administration of both agents (excludes enteric coated formulation of didanosine). Risk D: Consider therapy modification
Dronedarone: QTc-Prolonging Agents may enhance the QTc-prolonging effect of Dronedarone. Risk X: Avoid combination
Gadobutrol: May enhance the QTc-prolonging effect of QTc-Prolonging Agents. Risk D: Consider therapy modification
Insulin: May enhance the hyperglycemic effect of Quinolone Antibiotics. Insulin may enhance the hypoglycemic effect of Quinolone Antibiotics. Risk C: Monitor therapy
Iron Salts: May decrease the absorption of Quinolone Antibiotics. Of concern only with oral administration of both agents. Exceptions: Ferric Gluconate; Ferumoxytol; Iron Dextran Complex; Iron Sucrose. Risk D: Consider therapy modification
Lumefantrine: May enhance the QTc-prolonging effect of QTc-Prolonging Agents. Risk X: Avoid combination
Magnesium Salts: May decrease the absorption of Quinolone Antibiotics. Of concern only with oral administration of both agents. Risk D: Consider therapy modification
Mycophenolate: Quinolone Antibiotics may decrease the serum concentration of Mycophenolate. Specifically, quinolones may decrease concentrations of the active metabolite of mycophenolate. Risk C: Monitor therapy
Nilotinib: May enhance the QTc-prolonging effect of QTc-Prolonging Agents. Risk X: Avoid combination
Nonsteroidal Anti-Inflammatory Agents: May enhance the neuroexcitatory and/or seizure-potentiating effect of Quinolone Antibiotics. Risk C: Monitor therapy
Pimozide: QTc-Prolonging Agents may enhance the QTc-prolonging effect of Pimozide. Risk X: Avoid combination
Probenecid: May increase the serum concentration of Quinolone Antibiotics. Risk C: Monitor therapy
QTc-Prolonging Agents: May enhance the adverse/toxic effect of other QTc-Prolonging Agents. Their effects can be additive, causing life-threatening ventricular arrhythmias. Risk D: Consider therapy modification
Quinapril: May decrease the absorption of Quinolone Antibiotics. Of concern only with oral administration of quinolones. Risk D: Consider therapy modification
QuiNINE: QTc-Prolonging Agents may enhance the QTc-prolonging effect of QuiNINE. QuiNINE may enhance the QTc-prolonging effect of QTc-Prolonging Agents. Risk X: Avoid combination
Sevelamer: May decrease the absorption of Quinolone Antibiotics. Risk D: Consider therapy modification
Sucralfate: May decrease the absorption of Quinolone Antibiotics. Of concern only with oral administration of quinolones. Risk D: Consider therapy modification
Sulfonylureas: Quinolone Antibiotics may enhance the hypoglycemic effect of Sulfonylureas. This appears to be particularly concerning early in the course of combination therapy. Quinolone Antibiotics may diminish the hypoglycemic effect of Sulfonylureas. With longer-term combination, there is a greater risk of hyperglycemia. Risk C: Monitor therapy
Tetrabenazine: QTc-Prolonging Agents may enhance the QTc-prolonging effect of Tetrabenazine. Risk X: Avoid combination
Thioridazine: QTc-Prolonging Agents may enhance the QTc-prolonging effect of Thioridazine. Risk X: Avoid combination
Typhoid Vaccine: Antibiotics may diminish the therapeutic effect of Typhoid Vaccine. Only the live attenuated Ty21a strain is affected. Risk D: Consider therapy modification
Vitamin K Antagonists (eg, warfarin): Quinolone Antibiotics may enhance the anticoagulant effect of Vitamin K Antagonists. Risk C: Monitor therapy
Zinc Salts: May decrease the absorption of Quinolone Antibiotics. Of concern only with oral administration of both agents. Risk D: Consider therapy modification
Ziprasidone: QTc-Prolonging Agents may enhance the QTc-prolonging effect of Ziprasidone. The risk of a severe arrhythmia may be increased. Risk X: Avoid combination
Storage
Store between 15°C to 25°C (59°F to 77°F); do not freeze.
Mechanism of Action
Gatifloxacin is a DNA gyrase inhibitor, and also inhibits topoisomerase IV. DNA gyrase (topoisomerase II) is an essential bacterial enzyme that maintains the superhelical structure of DNA. DNA gyrase is required for DNA replication and transcription, DNA repair, recombination, and transposition; inhibition is bactericidal.
Pharmacodynamics/Kinetics
Absorption: Ophthalmic: Not measurable
Dosage
Ophthalmic: Children ?1 year and Adults: Bacterial conjunctivitis:
Days 1 and 2: Instill 1 drop into affected eye(s) every 2 hours while awake (maximum: 8 times/day)
Days 3-7: Instill 1 drop into affected eye(s) up to 4 times/day while awake
Monitoring Parameters
Signs of infection
Patient Education
Do not take any new medication during therapy without consulting prescriber. Use as directed: Tilt head back and instill prescribed number of drops in affected eye as often as directed for length of time prescribed. Do not allow dropper to touch any surface, including the eyes or hands. Apply light pressure to the inside corner of the eye (near the nose) after each drop. Avoid wearing contact lenses during treatment. May cause headache or dizziness (use caution when driving or engaging in tasks requiring alertness until response is known). May cause temporary stinging, burning, itching, redness, or tearing; eyelid swelling or itching; or a bad taste in mouth after instillation. Report persistent adverse reactions, visual disturbances, or if condition worsens. If you experience signs of allergic reaction (eg, itching, rash, respiratory difficulty, facial edema, difficulty swallowing), discontinue use immediately and report to prescriber. Pregnancy/breast-feeding precautions: Inform prescriber if you are or intend to be pregnant or breast-feed.
Geriatric Considerations
Evaluate the patient's ability to self-administer the ophthalmic product.
Anesthesia and Critical Care Concerns/Other Considerations
Gatifloxacin causes a dose-dependent QT prolongation. Coadministration of gatifloxacin with other drugs that also prolong the QT interval or induce bradycardia (eg, beta-blockers, amiodarone) should be done cautiously. Careful consideration should be given in the use of gatifloxacin in patients with cardiovascular disease, particularly in those with conduction abnormalities.
Cardiovascular Considerations
Gatifloxacin causes a dose-dependent QT prolongation. Coadministration of gatifloxacin with other drugs that also prolong the QT interval or induce bradycardia (eg, beta-blockers, amiodarone) should be avoided. Careful consideration should be given in the use of gatifloxacin in patients with cardiovascular disease, particularly in those with conduction abnormalities.
Dental Health: Effects on Dental Treatment
Key adverse event(s) related to dental treatment: Taste disturbance.
Dental Health: Vasoconstrictor/Local Anesthetic Precautions
Gatifloxacin is one of the drugs confirmed to prolong the QT interval and is accepted as having a risk of causing torsade de pointes. The risk of drug-induced torsade de pointes is extremely low when a single QT interval prolonging drug is prescribed. In terms of epinephrine, it is not known what effect vasoconstrictors in the local anesthetic regimen will have in patients with a known history of congenital prolonged QT interval or in patients taking any medication that prolongs the QT interval. Until more information is obtained, it is suggested that the clinician consult with the physician prior to the use of a vasoconstrictor in suspected patients, and that the vasoconstrictor (epinephrine, mepivacaine and levonordefrin [Carbocaine® 2% with Neo-Cobefrin®]) be used with caution.
Dental Comment
Gatifloxacin is known to prolong the QT interval. The QT interval is measured as the time and distance between the Q point of the QRS complex and the end of the T wave in the ECG tracing. After adjustment for heart rate, the QT interval is defined as prolonged if it is more than 450 msec in men and 460 msec in women. A long QT syndrome was first described in the 1950s and 60s as a congenital syndrome involving QT interval prolongation and syncope and sudden death. Some of the congenital long QT syndromes were characterized by a peculiar electrocardiographic appearance of the QRS complex involving a premature atria beat followed by a pause, then a subsequent sinus beat showing marked QT prolongation and deformity. This type of cardiac arrhythmia was originally termed “torsade de pointes” (translated from the French as “twisting of the points”). Gatifloxacin is considered as having a risk of causing torsade de pointes. Since it is not known what effect vasoconstrictors in the local anesthetic regimen will have in patients with a known history of congenital prolonged QT interval or in patients taking any medication that prolongs the QT interval, a medical consult is suggested.
Mental Health: Effects on Mental Status
Gatifloxacin may cause dizziness, insomnia; may rarely produce abnormal thinking, agitation, anorexia, anxiety, asthenia, ataxia, confusion, depersonalization, depression, euphoria, hallucination, hostility, nervousness, panic attacks, paranoia, psychosis, somnolence, or stress
Mental Health: Effects on Psychiatric Treatment
May have potential to prolong QT interval; should avoid in patients with uncorrected hypokalemia, or concurrent administration of other medications known to prolong the QT interval (antipsychotics, tricyclic antidepressants, ziprasidone)
Nursing: Physical Assessment/Monitoring
Assess allergy history and previous exposure to quinolone antibiotics before initiating therapy. Evaluate therapeutic effectiveness (resolution of infection) and adverse effects (eg, hypersensitivity) regularly during therapy. Teach patient appropriate use, possible side effects/appropriate interventions, and adverse symptoms to report.
Dosage Forms
Excipient information presented when available (limited, particularly for generics); consult specific product labeling.
Solution, ophthalmic:
Zymar®: 0.3% (5 mL) [contains benzalkonium chloride]
Pricing: U.S. (www.drugstore.com)
Solution (Zymar)
0.3% (5): $83.36
International Brand Names
Lexi-Comp.com
Last full review/revision January 2010
Content last modified January 2010
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