Antibiotic — Severe CAP / Legionella Pregnancy: Contraindicated in pregnancy and breast-feeding (UK SPC 4.3/4.6). US labelling: Pregnancy Category C.

Levofloxacin

Brand names: Tavanic

A fluoroquinolone antibiotic with broad respiratory activity used for community-acquired pneumonia and other respiratory infections, often when first-line agents are unsuitable. Its use is restricted owing to recognised serious adverse effects.

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: 500 mg

Route: oral

Frequency: once or twice daily

Respiratory context - UK SPC (normal renal function): community-acquired pneumonia 500 mg once or twice daily for 7-14 days; acute bacterial exacerbation of chronic bronchitis 500 mg once daily for 7-10 days; acute bacterial sinusitis 500 mg once daily for 10-14 days. (US labelling alternatives: nosocomial pneumonia 750 mg once daily for 7-14 days; community-acquired pneumonia 750 mg once daily for 5 days - verify vs UK SPC.) Use for acute sinusitis and acute exacerbation of chronic bronchitis only when adequately diagnosed. 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. 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

Levofloxacin inhibits bacterial DNA gyrase and topoisomerase IV, blocking DNA replication and producing a bactericidal effect against many respiratory pathogens.

Prescribing in practice

Reserve for situations where other antibiotics are inappropriate — the MHRA warns of rare but disabling and potentially irreversible tendon, musculoskeletal and neuropsychiatric effects, and patients should stop at the first sign of tendon pain.
It prolongs the QT interval, so use cautiously with other QT-prolonging drugs and in those with electrolyte disturbance or relevant cardiac risk.
It can lower the seizure threshold and interacts with cations and other agents, and tendon risk is higher in older patients and with corticosteroids.

Monitoring

Monitor clinical response and watch for tendon, joint or neurological symptoms, QT-related effects and signs of Clostridioides difficile-associated diarrhoea.

Counselling the patient

Stop the antibiotic and seek advice if you develop tendon pain or swelling, new numbness or significant mood changes.
Separate it from antacids, iron and dairy, and avoid excess sun exposure.

Evidence & guidelines

Levofloxacin is supported for respiratory infection in NICE and BTS guidance as a reserve agent given MHRA fluoroquinolone safety restrictions.

Reference: NICE NG138; MHRA Drug Safety Update (2019, 2023); BTS CAP Guidelines; PHE Legionella 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.

Calculators

Pathways