Fluoroquinolone antibiotic Pregnancy: Contraindicated in pregnancy and breast-feeding (UK SPC 4.3/4.6). US labelling: Pregnancy Category C.

Levofloxacin

Brand names: Tavanic

Levofloxacin is a fluoroquinolone antibacterial used for a range of infections including respiratory, urinary and some skin and soft-tissue infections, and as part of certain regimens for resistant tuberculosis.

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: 250 mg to 500 mg

Route: oral

Frequency: once or twice daily (depending on indication and severity)

UK SPC dose is indication-dependent (normal renal function, CrCl >50 ml/min): acute bacterial sinusitis 500 mg once daily 10-14 days; acute exacerbation of chronic bronchitis 500 mg once daily 7-10 days; community-acquired pneumonia 500 mg once or twice daily 7-14 days; acute pyelonephritis 500 mg once daily 7-10 days; uncomplicated cystitis 250 mg once daily 3 days; complicated UTI 500 mg once daily 7-14 days; chronic bacterial prostatitis 500 mg once daily 28 days; complicated skin and soft-tissue infection 500 mg once or twice daily 7-14 days; inhalation anthrax 500 mg once daily 8 weeks. Reserve for infections that are adequately diagnosed and where other antibacterials are inappropriate. Swallow whole; take at least 2 hours before or after iron/zinc salts, magnesium- or aluminium-containing antacids, didanosine or sucralfate. Oral and IV forms are bioequivalent (same dose). Contraindicated in children and growing adolescents (<18 years).

Dose adjustments

Renal

Required when CrCl <=50 ml/min. Example for a 500 mg/24 h regimen: first dose 500 mg, then CrCl 50-20 ml/min 250 mg/24 h; CrCl 19-10 ml/min 125 mg/24 h; CrCl <10 ml/min (incl. haemodialysis/CAPD) 125 mg/24 h. For the 250 mg/24 h and 500 mg/12 h regimens see the SPC table. No additional dose is needed after haemodialysis or CAPD.

Dose auto-extracted from UK Summary of Product Characteristics (SPC) via the eMC; US FDA prescribing information (openFDA / DailyMed) — cross-check; US labelling may differ from UK — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

Contraindications

Hypersensitivity to levofloxacin, other quinolones, or any of the excipients
Epilepsy
History of tendon disorders related to fluoroquinolone administration
Children or growing adolescents (<18 years)
Pregnancy
Breast-feeding

Side effects

Nausea
Headache
Diarrhoea
Insomnia
Dizziness
Constipation

Interactions

Iron/zinc salts, magnesium- or aluminium-containing antacids, didanosine, sucralfate - reduce levofloxacin absorption; separate doses by at least 2 hours (eMC 4.2; US label 7)
Warfarin - anticoagulant effect may be enhanced; monitor INR/prothrombin time and for bleeding (US label 7)
Antidiabetic agents - dysglycaemia reported; monitor blood glucose (US label 7)

Clinical monograph

How it works

It inhibits bacterial DNA gyrase (topoisomerase II) and topoisomerase IV, blocking DNA replication and transcription and leading to bacterial cell death.

Prescribing in practice

MHRA advice restricts fluoroquinolones to situations where other antibacterials are unsuitable because of rare but serious and potentially irreversible musculoskeletal and nervous-system effects, including tendon rupture and peripheral neuropathy.
It prolongs the QT interval and should be used with caution alongside other QT-prolonging drugs and in those with predisposing electrolyte disturbance or cardiac risk.
Absorption is markedly reduced by polyvalent cations, so it should be separated in time from antacids, iron, calcium and other multivalent-cation preparations.

Monitoring

Monitor for tendon pain, new neuropathic symptoms and signs of central nervous system effects, with attention to QT risk in susceptible patients.

Counselling the patient

Stop the medicine and seek advice if you get tendon pain or swelling, or new numbness, tingling or weakness.
Avoid taking it at the same time as indigestion remedies, or iron or calcium supplements.
Report any mood changes, confusion or unusual heartbeat sensations.

Evidence & guidelines

MHRA Drug Safety Updates have reinforced restrictions on fluoroquinolone use owing to the risk of disabling and potentially long-lasting adverse effects.

Reference: MHRA Drug Safety Update; UK AMR guidance; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Curated clinical cross-links plus same-class fallbacks.

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