Levofloxacin

Adult systemic labels cover susceptible nosocomial/community-acquired pneumonia, complicated/uncomplicated skin infections, chronic bacterial prostatitis, complicated/uncomplicated UTI, acute pyelonephritis, acute bacterial sinusitis, and acute bacterial exacerbation of chronic bronchitis. Because of serious risks, reserve treatment of uncomplicated UTI, bacterial sinusitis, or bacterial bronchitis exacerbation for patients without other treatment options. Culture/site/pathogen susceptibility determines appropriateness; the two pneumonia and UTI regimens have different organism-specific labeling, not automatic interchangeability.

Systemic use includes inhalational anthrax post-exposure and treatment/prophylaxis of plague, including pediatric patients ≥6 months; tablet strength/weight limitations still apply. Anthrax approval relies on a surrogate exposure endpoint and plague efficacy on animal evidence, not claimed human randomized trials. Ophthalmic 0.5% is for susceptible bacterial conjunctivitis; ophthalmic 1.5% is for susceptible corneal ulcer. Neither ophthalmic product is an oral liquid or a treatment for systemic infection.

The following oral/IV label regimens are once every 24 hours in adults with CrCl ≥50 mL/min; duration and organism/site restrictions remain indication-specific. They are label options, not a declaration that every listed infection should receive a fluoroquinolone. Reserve sinusitis, bronchitis exacerbation, and uncomplicated UTI for patients with no alternative treatment options.

Systemic pediatric indications are limited to anthrax post-exposure or plague from age 6 months, not routine pediatric infections. Tablet label: ≥50 kg 500 mg every 24 hours;30–<50 kg 250 mg every 12 hours; tablets cannot be given below 30 kg because of available strengths. Liquid/IV labels: >50 kg 500 mg every 24 hours; <50 kg 8 mg/kg every 12 hours, maximum 250 mg per dose. Those two labels leave EXACTLY 50 kg unassigned; obtain formulation-specific clarification rather than infer a liquid/IV regimen. Courses are 60 days for anthrax or 10–14 days for plague. Pediatric safety beyond 14 days and adult safety beyond 28 days are unstudied in these labels; prolonged anthrax treatment requires the benefit-risk judgment described there.

Use the row matching the normal-function prescribed regimen. Renal table applies to adults; it is not a validated pediatric renal algorithm. No adjustment at CrCl ≥50 mL/min. Hemodialysis/CAPD do not effectively remove levofloxacin, so a post-dialysis supplement is not required.

Tablets may be taken without regard to food; liquid 25 mg/mL is taken 1 hour before or 2 hours after food. Separate oral doses by at least 2 hours before/after magnesium/aluminum antacids, sucralfate, iron/zinc supplements, or buffered didanosine. Measure liquid with an accurate metric device; maintain adequate hydration. IV premix is 5 mg/mL: 250/500 mg infusions take at least 60 minutes and 750 mg at least 90 minutes. Never give rapid IV bolus, IM, SC, intrathecal, or intraperitoneal. Do not add medicines or run incompatible drugs through the same line; flush between sequential compatible infusions. Selected premix needs no additional dilution; concentrate vials require their own label.

For 0.5% conjunctivitis: days 1–2, 1–2 drops in the affected eye(s) every 2 hours while awake, up to 8 times/day; days 3–7 every 4 hours while awake, up to 4 times/day. For 1.5% corneal ulcer: days 1–3, 1–2 drops every 30 minutes to 2 hours while awake, plus approximately 4 and 6 hours after retiring; from day 4 to treatment completion, 1–2 drops every 1–4 hours while awake. Follow the eye specialist’s course and examination plan; the concentrated product is not a simple substitution for 0.5% conjunctivitis dosing. Avoid contaminating bottle tips and contact-lens wear with active infection.

Selected systemic labels contraindicate hypersensitivity to levofloxacin or other quinolones; ophthalmic labels also include hypersensitivity to any component. Myasthenia-gravis avoidance, prior serious fluoroquinolone reactions, QT-risk avoidance, and use restrictions are warnings/clinical selection requirements, not additional formal contraindications invented here.

Systemic labels box disabling and potentially irreversible tendon rupture/tendinitis, peripheral neuropathy, and CNS effects, plus exacerbation of myasthenia gravis. They direct immediate discontinuation for serious reactions and reserve certain otherwise uncomplicated infections for patients with no alternative treatment options. The selected ophthalmic labels contain no boxed warning; this does not mean allergy or ocular complications are impossible.

Common systemic reactions include nausea, headache, diarrhea, insomnia, constipation, and dizziness; IV-site reactions may occur. Ophthalmic products can cause discomfort/irritation, blurred vision, headache, or altered taste;1.5% trials frequently reported headache and taste disturbance. Suspected excess systemic exposure needs medical assessment, hydration and supportive management; dialysis is ineffective at removing drug. Significant eye reactions, accidental ingestion, or loss of vision require route-specific evaluation. Do not attempt gastric-emptying procedures at home.

Oral antacids/mineral cations, sucralfate, and buffered didanosine can reduce absorption; separate by at least 2 hours on either side. Warfarin effect/INR may increase in practice despite healthy-volunteer interaction studies; closely monitor INR and bleeding. These oral absorption instructions do not authorize IV admixture with cation-containing medicines.

Antidiabetic drugs/insulin require glucose monitoring. NSAIDs can increase CNS stimulation/seizure risk; monitor theophylline levels and clinical toxicity when combined, even though a controlled levofloxacin study did not show a significant PK effect. Avoid class IA/III antiarrhythmics and assess other QT-risk drugs. Corticosteroids increase tendon risk. Selected systemic labels do not require routine dose adjustment solely for digoxin, cyclosporine, probenecid, or cimetidine; renal-dose requirements still apply. Opiate urine immunoassays may be falsely positive and require confirmation. Ophthalmic labels do not establish the same complete systemic interaction model.

Current tablet labeling reports observational human pregnancy data without an identified drug-associated major-birth-defect signal; this does not prove safety. Liquid/IV and ophthalmic labels retain older benefit-risk language based on limited controlled human data. Levofloxacin enters milk after oral/IV dosing. Tablet labeling recommends avoiding breastfeeding or pumping/discarding during treatment and for 2 additional days for most indications, with a separate benefit-risk exception during anthrax exposure. Older liquid/IV labels frame a nursing-versus-drug decision; eye labels advise caution and lack direct milk measurements after ophthalmic dosing. These formulation-label differences are explicit, not an assertion that topical exposure equals systemic exposure.

Systemic pediatric use is labeled from 6 months only for anthrax/plague, with greater musculoskeletal adverse-event incidence and limited long-course safety data. Tablet weight restrictions and the liquid/IV exactly 50 kg gap remain relevant. BOTH selected ophthalmic labels say safety/effectiveness below 6 years is unestablished; do not import an unverified one-year cutoff from another product. Older adults have increased tendon, QT, renal-accumulation, and aneurysm risks; base systemic dose selection on renal function.

Systemic clearance falls below CrCl 50 mL/min, requiring the adult adjustment table; dialysis does not provide effective drug removal. Hepatic-impairment PK studies are lacking, but limited metabolism means major hepatic PK effects are not expected; this does not negate potentially severe hepatotoxicity. Eye labels supply no quantitative renal/hepatic adjustment algorithm; low measured exposure is not a reason to invent one.

Levofloxacin inhibits bacterial DNA gyrase and topoisomerase IV, interfering with DNA replication/transcription. Resistance can develop through target changes and other mechanisms, and cross-resistance occurs. Match the infection and organisms to culture/susceptibility evidence; eye concentrations and systemic regimens are not interchangeable coverage claims.

Tablet absolute bioavailability is approximately 99%; peak levels generally occur 1–2 hours after dosing. Systemic drug undergoes limited metabolism and is excreted largely unchanged in urine; usual plasma half-life is about 6–8 hours and is prolonged by renal impairment. Oral and IV exposure can support clinician-selected sequential therapy at the appropriate dose, but food rules differ for liquid versus tablets. Eye studies measure much lower plasma concentrations than standard oral dosing; they do not establish zero systemic exposure or a systemic infection dose.

Confirm bacterial indication, alternatives, allergy/class-reaction history, pathogen/site, renal function and prescribed regimen. Review QT/electrolyte, tendon, neurologic, myasthenia, aneurysm, glucose, and interaction risks. Follow clinical response, hydration, kidney function when indicated, glucose/INR with affected medicines, and ECG/electrolytes when clinically appropriate. Eye therapy needs examination/response follow-up, especially ulcers or superinfection. No one label laboratory schedule applies to every short course.

Stop systemic treatment and contact the clinician for tendon pain/swelling, burning/tingling/numbness/weakness, serious mood/confusion symptoms, rash, or jaundice; rest an affected tendon. Seek urgent help for severe allergy, severe hypoglycemia, or sudden severe chest/back/abdominal pain. Report persistent watery/bloody diarrhea even after the course. Limit excessive sun/UV exposure, follow food/mineral spacing, maintain fluids, and do not share antibiotics. Eye bottles are for eyes only; wash hands, avoid tip contact and contact lenses, and obtain assessment for worsening pain or vision. Do not confuse 25 mg/mL oral solution with 0.5% or 1.5% eye solution.

Chartwell tablets are white/off-white oval, marked CE opposite 150 (250 mg), 151 (500 mg), or 152 (750 mg); representative NDCs 62135-655-14, 62135-656-50, 62135-657-14. Lannett 25 mg/mL liquid is packaged in 100, 200, or 480 mL bottles (NDC 0527-1948-66,-68,-70). WG IV premix 250 mg/50 mL, 500 mg/100 mL, and 750 mg/150 mL bags have carton NDCs 44567-435-24,-436-24,-437-24. Advagen 0.5% eye bottle 5 mL NDC 72888-142-22; BPI 1.5% eye bottle 5 mL NDC 54288-140-01. Label identity is not a guarantee of local stock.

Covered oral tablets 250/500/750 mg and oral liquid 25 mg/mL are systemic products. Selected IV premix contains 5 mg/mL in 50, 100, or 150 mL 5% dextrose bags; IV concentrate vials excluded. Ophthalmic solutions are 0.5% (5 mg/mL) for conjunctivitis and 1.5% (15 mg/mL) for corneal ulcer. Legacy Levaquin/Quixin/Iquix names do not establish current branded availability or interchangeable bottle directions.

Tablets: 20–25°C in a well-closed child-resistant container as required. Oral liquid: 25°C with 15–30°C excursions. WG premix:at or below 25°C; brief 40°C exposure permitted by its label, avoid excessive heat, protect from freezing/light, inspect and discard compromised single-dose bags/unused contents. Advagen 0.5% eye solution: 20–25°C; BPI 1.5%: 15–25°C. Keep eye tips sterile and caps closed; no unsupported opened-bottle discard duration is invented.