Gatifloxacin dosing

The long-term (more than several weeks) use of gatifloxacin in children and adolescents has not been approved because of concerns about effects on bone and cartilage growth. The optimal dose is not known. 

A 79-year-old man with type 2 diabetes taking glibenclamide 10 mg/day and metformin 2.5 g/day became hypoglycemic after taking one dose of gatifloxacin 400 mg. The hypoglycemia continued for 24-48 hours. 

Gajjar DA, LaCreta FP, Kollia GD Stolz RR, Berger S, Smith WB, Swingle M, Grasela DM. Effect of multiple-dose gatifloxacin or ciprofloxacin on glucose homeostasis and insulin production in patients with non-insulin-depen-dent diabetes mellitus maintained with diet and exercise. Pharmacotherapy 2000 20(6 pt 2) 76S-86S. 

Delirium occurred in a 69-year-old white man with a history of depression, non-insulin-dependent diabetes mellitus, hypertension, and atherosclerotic disease who was treated with intravenous gatifloxacin 400 mg/day (276). After the first dose of gatifloxacin he had numerous hallucinations and the symptoms got worse after each dose. After withdrawal no further hallucinations occurred. 

Because of their broad potent bactericidal activity the fluoroquinolone antibiotics are also an appropriate topical therapy for nongonococcal hyperacute conjimc-tivitis. Topical moxifloxacin or gatifloxacin should be administered initially in a dose of two drops every hour. 

Since gatifloxacin has a high oral systemic availability (96%), oral and intravenous formulations are bioequivalent and interchangeable (8). It has a large volume of distribution (about 1.8 1/kg), low protein binding (about 20%), broad tissue distribution, and is primarily excreted unchanged in the urine (over 80%) (7). After daily repeated administration, there was predictable modest accumulation steady state concentrations were reached after the third dose (9). 

Intravenous gatifloxacin can cause dose-related local reactions (8). 

Gatifloxacin can be administered without dose modification in the elderly (24). 

Honeybourne D, Banerjee D, Andrews J, Wise R. Concentrations of gatifloxacin in plasma and pulmonary compartments following a single 400 mg oral dose in patients undergoing fibre-optic bronchoscopy. J Antimicrob Chemother 2001 48(l) 63-6. 

Gajjar DA, LaCreta FP, Uderman HD, Kollia GD, Duncan G, Birkhofer MJ, Grasela DM. A dose-escalation study of the safety, tolerability, and pharmacokinetics of intravenous gatifloxacin in healthy adult men. Pharmacotherapy 2000 20(6 Pt 2) S49-58. 

Three-day courses of trimethoprim-sulfamethoxazole or a flu-oroquinolone (e.g., ciprofloxacin, levofloxacin, norfloxacin, or gatifloxacin) are superior to single-dose therapies." " The flnoro-qninolone moxifloxacin is not recommended for nse in UTIs owing to the inadequate urinary concentrations. The use of amoxiciUm and sulfonamides is not recommended because of the high incidence of resistant coli. For most adult females, short-course therapy is the treatment of choice for uncomplicated lower UTIs. Short-conrse therapy is inappropriate for patients who have had previons infections caused by resistant bacteria, for male patients, and for patients with complicated UTIs. If symptoms do not respond or recur, a urine cniture should be obtained and conventional therapy with a snitable agent instituted. ... 

Mcllleron H, Norman J, Kanyok TP, Fourie PB, Horton J, Smith PJ. Elevated gatifloxacin and reduced rifampicin concentrations in a single-dose interaction study amongst healthy volunteers. J Antimicrob Chemother 2007 60(6) 1398-401. 

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