General: Because a rapid or bolus i.v. injection may result in hypotension, levofloxacin injection should only be administered by slow i.v, infusion over a period of 60 or 90 min depending on the dosage (see Dosage & Administration).
Although levofloxacin is more soluble than other quinolones, adequate hydration of patients receiving levofloxacin should be maintained to prevent the formation of a highly concentrated urine.
Administer levofloxacin with caution in the presence of renal insufficiency. Careful clinical observation and appropriate laboratory studies should be performed prior to and during therapy since elimination of levofloxacin may be reduced. In patients with impaired renal function (creatinine clearance <50 mL/min), adjustment of the dosage regimen is necessary to avoid the accumulation of levofloxacin due to decreased clearance. (See Pharmacology: Pharmacokinetics under Actions and Dosage & Administration.)
Moderate to severe phototoxicity reactions have been observed in patients exposed to direct sunlight while receiving drugs in this class. Excessive exposure to sunlight should be avoided. However, in clinical trials with levofloxacin, phototoxicity has been observed in <0.1% of patients. Therapy should be discontinued if phototoxicity (e.g., a skin eruption) occurs.
As with other quinolones, levofloxacin should be used with caution in any patient with a known or suspected CNS disorder that may predispose to seizures or lower the seizure threshold (e.g., severe cerebral arteriosclerosis, epilepsy) or in the presence of other risk factors that may predispose to seizures or lower the seizure threshold (e.g., certain drug therapy, renal dysfunction). (See Warnings and Interactions.)
As with other quinolones, disturbances of blood glucose, including symptomatic hyper- and hypoglycemia, have been reported, usually in diabetic patients receiving concomitant treatment with an oral hypoglycemic agent (e.g., glyburide/glibenclamide) or with insulin. In these patients, careful monitoring of blood glucose is recommended. If a hypoglycemic reaction occurs in a patient being treated with levofloxacin, levofloxacin should be discontinued immediately and appropriate therapy should be initiated immediately. (See Interactions and Adverse Reactions.)
Some quinolones, including levofloxacin, have been associated with prolongation of the QT interval on the electrocardiogram (see Pharmacology: Electrocardiogram under Actions) and infrequent cases of arrhythmia. During post-marketing surveillance, very rare cases of torsades de pointes have been reported in patients taking levofloxacin. These reports generally involved patients with concurrent medical conditions or concomitant medications that may have been contributory. The risk of arrhythmias may be reduced by avoiding concurrent use with other drugs that prolong the QT interval including class Ia or class III antiarrhythmic agents; In addition, use of levofloxacin in the presence of risk factors for torsades de pointes such as hypokalemia, significant bradycardia, and cardiomyopathy should be avoided.
As with any potent antimicrobial drug, periodic assessment of organ system functions, including renal, hepatic, and hematopoietic, is advisable during therapy. (See Warnings and Adverse Reactions.)
Information for Patients: Patients should be advised: to drink fluids liberally; that antacids containing magnesium or aluminum, as well as sucralfate, metal cations, e.g. iron, and multivitamin preparations with zinc or didanosine (Videx) chewable/buffered tablets or the pediatric powder for oral solution should be taken at least 2 hrs before or 2 hrs after oral levofloxacin administration (see Interactions); that oral levofloxacin can be taken without regard to meals; to discontinue treatment and inform the physician if the patient experiences pain, inflammation or rupture of a tendon, and to rest and refrain from exercise until the diagnosis of tendinitis or tendon rupture has been confidently excluded; that levofloxacin may be associated with hypersensitivity reactions, even following the 1st dose, and to discontinue the drug at the first sign of a skin rash, hives or other skin reactions, a rapid heartbeat, difficulty in swallowing or breathing, any swelling suggesting angioedema (e.g., swelling of the lips, tongue, face, tightness of the throat, hoarseness), or other symptoms of an allergic reaction (see Warnings and Adverse Reactions); to avoid excessive sunlight or artificial ultraviolet light while receiving levofloxacin and to discontinue therapy if phototoxicity (i.e., skin eruption) occurs; that if diabetic and being treated with insulin or an oral hypoglycemic agent and a hypoglycemic reaction occurs, levofloxacin should be discontinued and consult a physician (see Interactions); that concurrent administration of warfarin and levofloxacin has been associated with increases of the International Normalized Ratio (INR) or prothrombin time and clinical episodes of bleeding. Patients should notify their physician if they are taking warfarin; that convulsions have been reported in patients taking quinolones, including levofloxacin and to notify their physician before taking Cravit if there is a history of this condition.
Effects on the Ability to Drive or Operate Machinery: Patients should be advised that levofloxacin may cause neurologic adverse effects (e.g., dizziness, lightheadedness) and they should know how to react to levofloxacin before they operate an automobile or machinery or engage in other activities requiring mental alertness and coordination (see Warnings and Adverse Reactions).
Carcinogenicity, Mutagenicity & Impairment of Fertility: In a lifetime bioassay in rats, levofloxacin exhibited no carcinogenic potential following daily dietary administration for 2 years; the highest dose (100 mg/kg/day) was 1.4 times the highest recommended human dose (750 mg) based upon relative body surface area.
Levofloxacin was not mutagenic in the following assays: Ames bacterial mutation assay (S. typhimurium and E. coli), CHO/HGPRT forward mutation assay, mouse micronucleus test, mouse dominant lethal test, rat unscheduled DNA synthesis assay, and the mouse sister chromatid exchange assay. It was positive in the in vitro chromosomal aberration (CHL cell line) and sister chromatid exchange (CHL/IU cell line) assays.
Levofloxacin caused no impairment of fertility or reproductive performance in rats at oral doses as high as 360 mg/kg/day, corresponding to 4.2 times the highest recommended human dose based upon relative body surface area and i.v. doses as high as 100 mg/kg/day, corresponding to 1.2 times the highest recommended human dose based upon relative body surface area.
Teratogenicity: Pregnancy Category C: Levofloxacin was not teratogenic in rats at oral doses as high as 810 mg/kg/day, which corresponds to 9.4 times the highest recommended human dose based upon relative body surface area or at i.v. doses as high as 160 mg/kg/day, corresponding to 1.9 times the highest recommended human dose based upon relative body surface area. The oral dose of 810 mg/kg/day to rats caused decreased fetal body weight and increased fetal mortality. No teratogenicity was observed when rabbits were dosed orally as high as 50 mg/kg/day, which corresponds to 1.1 times the highest recommended human dose based upon relative body surface area or when dosed intravenously as high as 25 mg/kg/day, corresponding to 0.5 times the highest recommended human dose based upon relative body surface area.
Use in pregnancy: There are, however, no adequate and well-controlled studies in pregnant women. Levofloxacin should be used during pregnancy only if the potential benefit justifies potential risk to the fetus (see Warnings).
Use in lactation: Levofloxacin has not been measured in human milk. Based upon data from ofloxacin, it can be presumed that levofloxacin will be excreted in human milk. Because of the potential for serious adverse reactions from levofloxacin in nursing infants, a decision should be made whether to discontinue nursing or to discontinue the drug taking into account the importance of the drug to the mother.
Use in children: Safety and effectiveness in pediatric patients and adolescents <18 years have not been established. Quinolones, including levofloxacin, cause arthropathy and osteochondrosis in juvenile animals of several species (see Warnings.)
Use in the elderly: In phase 3 clinical trials, 1190 levofloxacin-treated patients (25%) were more than or equal to 65 years. Of these, 675 patients (14%) were between 65 and 74 years and 515 patients (11%) were 75 years or older. No overall differences in safety or effectiveness were observed between these subjects and younger subjects and other reported clinical experience has not identified differences in responses between the elderly and younger patients, but greater sensitivity of some older individuals cannot be ruled out.
The pharmacokinetic properties of levofloxacin in younger adults and elderly adults do not differ significantly when creatinine clearance is taken into consideration. However, since the drug is known to be substantially excreted by the kidney, the risk of toxic reactions to levofloxacin may be greater in patients with impaired renal function. Because elderly patients are more likely to have decreased renal function, care should be taken in dose selection and it may be useful to monitor renal function.