LEVOFLOXACIN IN DEXTROSE 5% IN PLASTIC CONTAINER
Clinical safety rating: caution
Animal studies have proved adverse effects but may be safe for humans
Levofloxacin is a fluoroquinolone antibiotic that inhibits bacterial DNA gyrase (topoisomerase II) and topoisomerase IV, thereby inhibiting DNA replication and transcription.
| Metabolism | Levofloxacin is minimally metabolized in the liver; approximately 87% of the drug is excreted unchanged in the urine. It is not extensively metabolized by CYP450 enzymes. |
| Excretion | Renal: ~87% of dose excreted unchanged in urine via glomerular filtration and tubular secretion; biliary/fecal: <5% eliminated as unchanged drug and metabolites; <4% recovered in feces. |
| Half-life | 6-8 hours in patients with normal renal function (creatinine clearance >50 mL/min); increases to 20-48 hours in severe renal impairment (CrCl <20 mL/min); clinically relevant for dosing interval adjustment. |
| Protein binding | ~24-38%, primarily bound to albumin. |
| Volume of Distribution | 1.1-1.5 L/kg, indicating extensive extravascular tissue distribution; penetrates into lung, skin, bone, and cerebrospinal fluid. |
| Bioavailability | Intravenous: 100% (administered IV). Oral: ~99% (for oral levofloxacin, not applicable to IV form). |
| Onset of Action | Intravenous: peak plasma concentrations achieved by end of 60-90 min infusion; therapeutic effect typically within 24-48 hours for susceptible infections. |
| Duration of Action | Duration of antimicrobial effect approximately 12-24 hours based on AUC/MIC ratio; clinical dosing every 24 hours for most indications; post-antibiotic effect (PAE) of 1-2 hours for Gram-positive and 4-8 hours for Gram-negative organisms. |
500 mg or 750 mg intravenously once daily. Infusion over 60-90 minutes.
| Dosage form | INJECTABLE |
| Renal impairment | CrCl 20-49 mL/min: 500 mg initial dose, then 250 mg every 24 hours; CrCl 10-19 mL/min: 500 mg initial dose, then 250 mg every 48 hours; CrCl < 10 mL/min: 500 mg initial dose, then 250 mg every 48 hours. For 750 mg dose: CrCl 20-49 mL/min: 750 mg initial, then 500 mg every 24 hours; CrCl 10-19 mL/min: 750 mg initial, then 500 mg every 48 hours; CrCl < 10 mL/min: 750 mg initial, then 500 mg every 48 hours. |
| Liver impairment | No dose adjustment required for mild to moderate hepatic impairment (Child-Pugh A and B). Not studied in severe hepatic impairment (Child-Pugh C); use with caution. |
| Pediatric use | Not recommended for children < 18 years except for specific indications (e.g., inhalational anthrax, plague). Anthrax (post-exposure): 8 mg/kg IV every 12 hours (max 250 mg per dose) for 60 days. Other indications: 6-8 mg/kg IV every 12 hours (max 250 mg per dose) for 14-28 days. |
| Geriatric use | No specific dose adjustment based solely on age. Use caution due to increased risk of tendinitis/tendon rupture and renal function decline; adjust dose based on CrCl. Monitor renal function and nervous system adverse effects. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Chelates with divalent cations (antacids Ca2+ Fe2+) reducing absorption May enhance effects of warfarin Associated with tendonitis and tendon rupture.
| Breastfeeding | Levofloxacin is excreted into human milk. M/P ratio approximately 0.56-0.81. Peak milk concentrations 2-4 hours after dose. Theoretical risk of arthropathy in nursing infants; consider discontinuing breastfeeding or drug, especially in neonates or infants. American Academy of Pediatrics considers maternal use compatible with breastfeeding if exposure is minimal. |
| Teratogenic Risk | Fluoroquinolones, including levofloxacin, are associated with arthropathy and cartilage damage in immature animals. Human data suggest an increased risk of musculoskeletal disorders and tendon rupture in children. First trimester: limited human data; animal studies show no evidence of teratogenicity at clinically relevant doses, but potential for fetal cartilage damage. Second and third trimesters: potential fetal cartilage damage and arthropathy; use only if benefit outweighs risk, especially during periods of rapid skeletal growth. FDA Pregnancy Category C. |
■ FDA Black Box Warning
Fluoroquinolones, including levofloxacin, are associated with an increased risk of tendinitis and tendon rupture in all ages. This risk is further increased in patients over 60 years of age, those taking corticosteroids, and those with kidney, heart, or lung transplants. Levofloxacin may exacerbate muscle weakness in persons with myasthenia gravis. Serious adverse reactions, including tendinitis, tendon rupture, peripheral neuropathy, and central nervous system effects, may occur within hours to weeks after starting therapy.
| Common Effects | Headache Dizziness Nausea Constipation Diarrhea |
| Serious Effects |
["Hypersensitivity to levofloxacin or any fluoroquinolone","History of tendinitis or tendon rupture associated with fluoroquinolone use","Myasthenia gravis","Children (except for specific indications like inhalational anthrax)"]
| Precautions | ["Tendinopathy and tendon rupture","Peripheral neuropathy","Central nervous system effects (e.g., dizziness, seizures, increased intracranial pressure)","Exacerbation of myasthenia gravis","Hypersensitivity reactions","Clostridioides difficile-associated diarrhea","Blood glucose disturbances (especially in diabetic patients on insulin or oral hypoglycemics)","Photosensitivity/phototoxicity","QT prolongation","Renal impairment (dose adjustment required)","Avoid in patients with known QT prolongation or uncorrected electrolyte disturbances"] |
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| Fetal Monitoring | Monitor maternal: renal function, liver function, blood glucose (risk of dysglycemia), complete blood count, signs of tendonitis or tendon rupture, CNS effects (seizures, dizziness). Fetal/neonatal: no specific monitoring required; assess for musculoskeletal development if prolonged exposure in utero. |
| Fertility Effects | No significant effects on fertility in animal studies. In humans, no well-documented effects on fertility. Fluoroquinolones are not known to impair reproductive function. |