MAXAQUIN
Clinical safety rating: caution
Comprehensive clinical and safety monograph for MAXAQUIN (MAXAQUIN).
Fluoroquinolone antibiotic that inhibits bacterial DNA gyrase (topoisomerase II) and topoisomerase IV, thereby interfering with DNA replication, transcription, repair, and recombination.
| Metabolism | Hepatic metabolism via glucuronidation and sulfation; minor CYP450 involvement. Excreted primarily unchanged in urine (40-60%) and feces (20-40%). |
| Excretion | Renal excretion of unchanged drug accounts for 70-80%; biliary/fecal elimination accounts for 20-30%. |
| Half-life | Terminal elimination half-life is approximately 12 hours (range 10-14 hours), supporting twice-daily dosing for systemic infections. |
| Protein binding | 30-40% bound to serum albumin. |
| Volume of Distribution | 1.5-2.0 L/kg, indicating extensive extravascular distribution. |
| Bioavailability | Oral: 90-100%. |
| Onset of Action | Oral: 1-2 hours; intravenous: immediate (within minutes for clinical effect). |
| Duration of Action | Approximately 12 hours, consistent with dosing interval of every 12 hours for most indications. |
| Molecular Weight | 352.4 |
400 mg orally once daily for 5-10 days; for complicated urinary tract infections, 400 mg orally once daily for 10-14 days.
| Dosage form | TABLET |
| Renal impairment | CrCl ≥30 mL/min: no adjustment; CrCl <30 mL/min or hemodialysis: 400 mg orally every 48 hours; peritoneal dialysis: 400 mg orally every 48 hours. |
| Liver impairment | No adjustment required for mild to moderate hepatic impairment; not studied in severe impairment, use with caution. |
| Pediatric use | Not recommended for patients <18 years of age due to risk of arthropathy. |
| Geriatric use | No specific dose adjustment; consider renal function and potential increased risk of tendon rupture; start at lower end of dosing range if renal impairment present. |
| 1st trimester | Contraindicated due to potential arthropathy and cartilage damage in developing fetus. |
| 2nd trimester | Contraindicated; fluoroquinolones may cause fetal cartilage erosion. |
| 3rd trimester | Contraindicated; risk of fetal joint harm and CNS effects. |
Clinical note
Comprehensive clinical and safety monograph for MAXAQUIN (MAXAQUIN).
| Placental transfer | Crosses placenta; found in fetal tissues. |
| Breastfeeding | Excreted into breast milk; potential for joint damage in nursing infant. Avoid use during breastfeeding unless no alternative. |
| Lactation Rating | L5 (Contraindicated) |
■ FDA Black Box Warning
Fluoroquinolones, including MAXAQUIN, have been 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, in patients taking corticosteroids, and in patients with kidney, heart, or lung transplants.
| Serious Effects |
Hypersensitivity to MAXAQUIN or other fluoroquinolonesPregnancyLactationHistory of tendon disorders with fluoroquinolonesChildren under 18 years (except for specific infections)Prolonged QT interval or concurrent QT-prolonging drugs
| Precautions | Tendon damage: discontinue at first sign of tendon pain, swelling, or inflammation., Exacerbation of myasthenia gravis: avoid use in patients with known history., Neuropathy: peripheral neuropathy may occur rapidly; discontinue if symptoms develop., CNS effects: may cause dizziness, confusion, and increased intracranial pressure; use with caution in patients with CNS disorders., QT prolongation: avoid in patients with known QT prolongation, electrolyte abnormalities, or concurrent use of Class IA/III antiarrhythmics., Hypersensitivity reactions: serious and occasionally fatal anaphylactic reactions have been reported., Photosensitivity: avoid excessive sunlight or UV light., Renal impairment: dose adjustment required for creatinine clearance <30 mL/min., C. difficile-associated diarrhea: consider discontinuation if diarrhea occurs. |
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| Teratogenic Risk | Fluoroquinolones cross the placenta. In animal studies, no consistent teratogenicity observed but arthropathy reported in juvenile animals. Human data insufficient; use only if benefit outweighs risk. Avoid in first trimester if possible. |
| Fetal Monitoring | Monitor for maternal adverse effects (tendonitis, QT prolongation). Fetal monitoring not required specifically, but consider fetal ultrasound if prolonged use. |
| Fertility Effects | No specific data on fertility effects. Fluoroquinolones may affect sperm motility in animal studies; clinical significance unknown. |
| Food/Dietary | Avoid calcium-fortified foods and dairy products (milk, yogurt) within 2 hours of taking MAXAQUIN, as calcium can chelate and reduce absorption. No other significant food interactions reported. |
| Clinical Pearls | MAXAQUIN (lomefloxacin) is a fluoroquinolone with enhanced activity against gram-negative pathogens but limited coverage against anaerobes and gram-positive cocci, especially Streptococcus pneumoniae. It is associated with a high risk of phototoxicity and should not be used for community-acquired pneumonia due to lack of efficacy. Renal dose adjustment is required for creatinine clearance <40 mL/min. Avoid in patients with prolonged QT interval or those on antiarrhythmics due to risk of torsades de pointes. Monitor for tendonitis or tendon rupture, especially in patients over 60, those on corticosteroids, or with renal transplant. |
| Patient Advice | Take this medication exactly as prescribed, usually once daily with or without food. Do not skip doses or double up. · Avoid excessive sunlight or tanning beds during treatment and for at least 2 weeks after stopping; use sunscreen and protective clothing to prevent severe sunburn or skin reactions. · Drink plenty of fluids to prevent crystal formation in urine, unless instructed otherwise by your doctor. · If you experience sudden pain, swelling, or snapping sound in a tendon (especially Achilles), stop the drug and contact your doctor immediately. · Report any symptoms like irregular heartbeat, fainting, or dizziness, as this drug can cause QT prolongation. · This medication may cause dizziness or lightheadedness; avoid driving or operating heavy machinery until you know how it affects you. · Do not take this medication within 2 hours of antacids, sucralfate, iron, or multivitamins containing zinc or magnesium, as they reduce absorption. · Complete the full course even if you feel better; do not share this medication with others. |