Gatifloxacin

Indications

Oral
Respiratory tract infections
Adult: 400 mg once daily.
Renal impairment: Patients on haemodialysis or continuous peritoneal dialysis: Initially, 400 mg/day. Maintenance dose: 200 mg daily.

CrCl (ml/min)	Dosage Recommendation
<40	Initially, 400 mg/day. Maintenance dose: 200 mg daily.

Oral
Susceptible infections
Adult: 400 mg once daily.
Renal impairment: Patients on haemodialysis or continuous peritoneal dialysis: Initially, 400 mg/day. Maintenance dose: 200 mg daily.

CrCl (ml/min)	Dosage Recommendation
<40	Initially, 400 mg/day. Maintenance dose: 200 mg daily.

Oral
Urinary tract infections
Adult: 400 mg once daily.
Renal impairment: Patients on haemodialysis or continuous peritoneal dialysis: Initially, 400 mg/day. Maintenance dose: 200 mg daily.

CrCl (ml/min)	Dosage Recommendation
<40	Initially, 400 mg/day. Maintenance dose: 200 mg daily.

Oral
Uncomplicated gonorrhoea
Adult: 400 mg as a single dose.
Oral
Uncomplicated urinary tract infections
Adult: 400 mg as a single dose or 200 mg daily for 3 days.
Renal impairment: Patients on haemodialysis or continuous peritoneal dialysis: Initially, 400 mg/day. Maintenance dose: 200 mg daily.

CrCl (ml/min)	Dosage Recommendation
<40	Initially, 400 mg/day. Maintenance dose: 200 mg daily.

Intravenous
Respiratory tract infections
Adult: 400 mg once daily, infused as a 2 mg/ml solution over 60 minutes.
Renal impairment: Patients on haemodialysis or continuous peritoneal dialysis: Initially, 400 mg/day. Maintenance dose: 200 mg daily.

CrCl (ml/min)	Dosage Recommendation
<40	Initially, 400 mg/day. Maintenance dose: 200 mg daily.

Intravenous
Susceptible infections
Adult: 400 mg once daily, infused as a 2 mg/ml solution over 60 minutes.
Renal impairment: Patients on haemodialysis or continuous peritoneal dialysis: Initially, 400 mg/day. Maintenance dose: 200 mg daily.

CrCl (ml/min)	Dosage Recommendation
<40	Initially, 400 mg/day. Maintenance dose: 200 mg daily.

Intravenous
Urinary tract infections
Adult: 400 mg once daily, infused as a 2 mg/ml solution over 60 minutes.
Renal impairment: Patients on haemodialysis or continuous peritoneal dialysis: Initially, 400 mg/day. Maintenance dose: 200 mg daily.

CrCl (ml/min)	Dosage Recommendation
<40	Initially, 400 mg/day. Maintenance dose: 200 mg daily.

Ophthalmic
Conjunctivitis
Adult: As a 0.3% solution: Instill 1 drop 2 hrly into affected eye(s) up to 8 times daily for the 1st 2 days, then reduce to 1 drop 4 times daily on days 3-7.

Special Populations: Renal impairment: Oral, IV ClCr ≤40 mL/min: Initially, 400 mg then 200 mg every 24 hrs.

Contraindications

Hypersensitivity; children <18 yr; concurrent use of class IA or III antiarrhythmics, QT-prolongation drugs; diabetics; pregnancy, lactation.

Warnings / Precautions

May prolong QT interval; uncorrected hypokalaemia; known or suspected CNS disorders, renal and hepatic impairment. Elderly.

Adverse Reactions

Rapid heartbeat, mental confusion, hallucinations, agitation, nightmares, depression; photophobia; tendon rupture; headache, dizziness, insomnia, chills, fever; back pain, abdominal pain; constipation, nausea, vomiting, diarrhoea, inflammation of the tongue, mouth sores; abnormal vision, ringing in the ears, vaginitis.
Potentially Fatal: Hyperosmolar nonketotic hyperglycaemic coma, diabetic ketoacidosis, hypoglycaemic coma, convulsions and mental status changes.

Drug Interactions

Antacids, ferrous salts, bismuth subsalicylate, sucralfate and zinc salts reduce bioavailability of gatifloxacin. May increase digoxin plasma levels. Probenecid, cimetidine and loop diuretics increase gatifloxacin levels. NSAIDs may increase the risk of CNS stimulation and convulsions. Concurrent use of bepridil, cisapride, erythromycin, pentamidine, phenothiazines, or TCAs may prolong QT interval. Concurrent corticosteroid therapy may increase the risk of tendon rupture. Increased risk of hypoglycaemia when used with oral antidiabetic agents. May enhance hypoprothrombinaemic effects of oral anticoagulants.
Potentially Fatal: Increased risk of adverse CV reactions when used with class IA or III antiarrhythmics e.g. disopyramide and amiodarone.
See Below for More gatifloxacin Drug Interactions

Mechanism of Actions

Gatifloxacin promotes breakage of double-stranded DNA in susceptible organisms and inhibits DNA gyrase, which is essential in reproduction of bacterial DNA.
Absorption: Absorbed readily form the GI tract (oral); peak plasma concentrations after 1-2 hr. Bioavailability: 96%.
Distribution: Widely distributed into body tissues. Protein-binding: 20%.
Metabolism: Limited metabolism.
Excretion: Via the urine (as unchanged and 1% metabolite); via the faeces (5% as unchanged). Limited metabolism; 7-14 hr (elimination half-life).

Pregnancy Category

Pregnancy Category C Since there are no adequate and well-controlled studies in pregnant women

gatifloxacin solution should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.

Storage Conditions

Intravenous: Store at 25°C. Ophthalmic: Store at 15-25°C. Oral: Store at 25°C.

ATC Classification

J01MA16 - gatifloxacin ; Belongs to the class of fluoroquinolones. Used in the systemic treatment of infections.
S01AX21 - gatifloxacin ; Belongs to the class of other antiinfectives. Used in the treatment of eye infections.