ZYMAXID

Clinical safety rating: caution

Comprehensive clinical and safety monograph for ZYMAXID (ZYMAXID).

How it works

Gatifloxacin is a fluoroquinolone antibiotic that inhibits bacterial DNA gyrase (topoisomerase II) and topoisomerase IV, leading to inhibition of DNA replication and transcription.

What the body does with it

Metabolism	Gatifloxacin is not extensively metabolized; less than 1% of the dose is metabolized. It is eliminated primarily as unchanged drug in urine via glomerular filtration and tubular secretion.
Excretion	Primarily renal excretion as unchanged drug (approximately 80-90% of administered dose). Minimal biliary/fecal elimination (<5%).
Half-life	Terminal elimination half-life is approximately 2-4 hours in patients with normal renal function. In renal impairment, half-life may be prolonged up to 8-12 hours, requiring dose adjustment.
Protein binding	Plasma protein binding is approximately 15-25%, primarily to albumin. Low binding minimizes drug interactions.
Volume of Distribution	Volume of distribution is approximately 0.2-0.4 L/kg, indicating distribution primarily into extracellular fluid and minimal tissue penetration.
Bioavailability	Oral bioavailability is approximately 70-80% due to good absorption. Ophthalmic solution has negligible systemic bioavailability (<0.5%).
Onset of Action	Oral administration: Onset of action occurs within 1-2 hours post-dose, with peak serum concentrations achieved by 1-2 hours. Ophthalmic solution: Onset of tear film concentration within minutes; systemic absorption negligible.
Duration of Action	Duration of action is approximately 6-8 hours for systemic effects. For ophthalmic use, local effects last up to 12 hours with twice-daily dosing.

Classification & Brands

Dosing & administration

1 drop of 0.5% ophthalmic solution in the affected eye(s) every 4 to 6 hours while awake for 7 days.

Dosage form	SOLUTION/DROPS
Renal impairment	No dose adjustment required for systemic exposure; however, use with caution in patients with severe renal impairment (CrCl <30 mL/min) due to limited data.
Liver impairment	No dose adjustment required for mild to moderate hepatic impairment; not studied in severe hepatic impairment.
Pediatric use	For children ≥1 year: 1 drop of 0.5% ophthalmic solution in the affected eye(s) every 4 to 6 hours while awake for 7 days. Safety and efficacy in infants <1 year not established.
Geriatric use	No specific dose adjustment; use standard adult dosing. Monitor for adverse effects due to potential age-related ocular surface changes and polypharmacy.

Use during pregnancy

1st trimester	Consult provider
2nd trimester	Consult provider
3rd trimester	Consult provider

Clinical note

Comprehensive clinical and safety monograph for ZYMAXID (ZYMAXID).

Breastfeeding	Unknown if gatifloxacin is excreted in human milk after ophthalmic administration. Due to low systemic absorption, negligible amounts are expected. Caution advised; M/P ratio not determined.
Teratogenic Risk	ZYMAXID (gatifloxacin ophthalmic solution) has minimal systemic absorption. No adequate and well-controlled studies in pregnant women. Animal studies show no evidence of teratogenicity at ocular doses. Risk to fetus is low, but use only if clearly needed.
Fetal Monitoring

Warnings & precautions

■ FDA Black Box Warning

Fluoroquinolones, including gatifloxacin, are associated with an increased risk of tendinitis and tendon rupture in all ages. This risk is further increased in patients older than 60 years, in patients taking corticosteroids, and in patients with kidney, heart, or lung transplants.

Side Effect Profile

Serious Effects

Absolute Contraindications

["Hypersensitivity to gatifloxacin or any other fluoroquinolone","History of tendinitis or tendon rupture with fluoroquinolone use"]

Clinical Precautions

Precautions

["Hypersensitivity reactions: serious and occasionally fatal anaphylactic reactions have been reported.","Discontinue at first sign of skin rash or any other sign of hypersensitivity.","Prolonged use may result in overgrowth of nonsusceptible organisms including fungi.","Avoid contact lens wear during treatment of conjunctivitis."]

Clinical Tips & Counseling

Drug interactions

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ZYMAXID

Clinical safety rating: caution

Comprehensive clinical and safety monograph for ZYMAXID (ZYMAXID).

How it works

Gatifloxacin is a fluoroquinolone antibiotic that inhibits bacterial DNA gyrase (topoisomerase II) and topoisomerase IV, leading to inhibition of DNA replication and transcription.

What the body does with it

Metabolism	Gatifloxacin is not extensively metabolized; less than 1% of the dose is metabolized. It is eliminated primarily as unchanged drug in urine via glomerular filtration and tubular secretion.
Excretion	Primarily renal excretion as unchanged drug (approximately 80-90% of administered dose). Minimal biliary/fecal elimination (<5%).
Half-life	Terminal elimination half-life is approximately 2-4 hours in patients with normal renal function. In renal impairment, half-life may be prolonged up to 8-12 hours, requiring dose adjustment.
Protein binding	Plasma protein binding is approximately 15-25%, primarily to albumin. Low binding minimizes drug interactions.
Volume of Distribution	Volume of distribution is approximately 0.2-0.4 L/kg, indicating distribution primarily into extracellular fluid and minimal tissue penetration.
Bioavailability	Oral bioavailability is approximately 70-80% due to good absorption. Ophthalmic solution has negligible systemic bioavailability (<0.5%).
Onset of Action	Oral administration: Onset of action occurs within 1-2 hours post-dose, with peak serum concentrations achieved by 1-2 hours. Ophthalmic solution: Onset of tear film concentration within minutes; systemic absorption negligible.
Duration of Action	Duration of action is approximately 6-8 hours for systemic effects. For ophthalmic use, local effects last up to 12 hours with twice-daily dosing.

Classification & Brands

Dosing & administration

1 drop of 0.5% ophthalmic solution in the affected eye(s) every 4 to 6 hours while awake for 7 days.

Dosage form	SOLUTION/DROPS
Renal impairment	No dose adjustment required for systemic exposure; however, use with caution in patients with severe renal impairment (CrCl <30 mL/min) due to limited data.
Liver impairment	No dose adjustment required for mild to moderate hepatic impairment; not studied in severe hepatic impairment.
Pediatric use	For children ≥1 year: 1 drop of 0.5% ophthalmic solution in the affected eye(s) every 4 to 6 hours while awake for 7 days. Safety and efficacy in infants <1 year not established.
Geriatric use	No specific dose adjustment; use standard adult dosing. Monitor for adverse effects due to potential age-related ocular surface changes and polypharmacy.

Use during pregnancy

1st trimester	Consult provider
2nd trimester	Consult provider
3rd trimester	Consult provider

Clinical note

Comprehensive clinical and safety monograph for ZYMAXID (ZYMAXID).

Breastfeeding	Unknown if gatifloxacin is excreted in human milk after ophthalmic administration. Due to low systemic absorption, negligible amounts are expected. Caution advised; M/P ratio not determined.
Teratogenic Risk	ZYMAXID (gatifloxacin ophthalmic solution) has minimal systemic absorption. No adequate and well-controlled studies in pregnant women. Animal studies show no evidence of teratogenicity at ocular doses. Risk to fetus is low, but use only if clearly needed.
Fetal Monitoring

Warnings & precautions

■ FDA Black Box Warning

Side Effect Profile

Serious Effects

Absolute Contraindications

["Hypersensitivity to gatifloxacin or any other fluoroquinolone","History of tendinitis or tendon rupture with fluoroquinolone use"]