Fluoroquinolone antibiotic Pregnancy: eMC §4.6: delafloxacin is CONTRAINDICATED during pregnancy and in women of childbearing potential not using contraception. There are no or limited data in pregnant women and animal studies have shown reproductive toxicity. Women of childbearing potential must use effective contraception during treatment. Breast-feeding is also contraindicated during treatment - it is unknown whether delafloxacin/metabolites are excreted in human milk, animal data show excretion in milk, and a risk to newborns/infants cannot be excluded.

Delafloxacin

Brand names: Quofenix

Delafloxacin is a fluoroquinolone antibacterial used for acute bacterial skin and skin-structure infections and certain community-acquired pneumonias.

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: 300 mg by intravenous infusion every 12 hours; switch to delafloxacin 450 mg tablet orally every 12 hours is possible at the discretion of the physician

Route: Intravenous infusion administered over 60 minutes (oral tablet as a switch option)

Frequency: Every 12 hours

eMC SPC §4.2 (Quofenix 300 mg powder for concentrate for solution for infusion). DURATION: total duration of treatment is 5 to 14 days for acute bacterial skin and skin structure infections (ABSSSI) and 5 to 10 days for community-acquired pneumonia (CAP). Each intravenous dose is given over 60 minutes; see SPC §6.6 for reconstitution and dilution instructions. ELDERLY: no dose adjustment required, but as with the fluoroquinolone class patients aged over 60 years are at increased risk of severe tendon disorders including tendon rupture. HEPATIC IMPAIRMENT: no dosage adjustment necessary. PAEDIATRIC: contraindicated in children and growing adolescents below 18 years of age (eMC §4.2/§4.3). CONTRACEPTION: if women of sexually mature age are treated, effective contraception must be used during treatment (§4.4). CLASS SAFETY (§4.4): avoid in patients who have experienced serious adverse reactions with any quinolone or fluoroquinolone previously - only initiate in the absence of alternative treatment options after careful benefit/risk assessment; discontinue at the first signs of tendinitis or tendon rupture, and counsel patients about aortic aneurysm/dissection and heart valve regurgitation risk (seek immediate medical attention for sudden abdominal, chest or back pain, acute dyspnoea, new palpitations or oedema). US CROSS-CHECK (openFDA, Baxdela, US labelling may differ): same regimen - 300 mg by intravenous infusion over 60 minutes every 12 hours, or a 450 mg tablet orally every 12 hours, for ABSSSI (5-14 days) or community-acquired bacterial pneumonia (5-10 days); tablets may be taken with or without food and must be given at least 2 hours before or 6 hours after antacids containing magnesium or aluminium, sucralfate, metal cations such as iron, or multivitamins containing zinc or iron.

Dose adjustments

Renal

eMC §4.2: no dose adjustment necessary in mild to moderate renal impairment (creatinine clearance >= 30 mL/min). In severe renal impairment (CrCl < 30 mL/min) the intravenous dose should be decreased to 200 mg every 12 hours; alternatively patients should receive 450 mg orally every 12 hours. Not recommended in patients with end stage renal disease. (US labelling, for cross-check, expresses the same adjustment by eGFR: 30-89 mL/min/1.73m2 no adjustment; 15-29 mL/min/1.73m2 intravenous 200 mg every 12 hours with no oral adjustment; ESRD < 15 including haemodialysis not recommended.)

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 the active substance or to any of the excipients (eMC §4.3)
Hypersensitivity to any fluoroquinolone or quinolone antibacterial medicinal product
Previous history of tendon disorders related to fluoroquinolone administration
Pregnancy, women of childbearing potential not using contraception, and breast-feeding (eMC §4.6)
Children or growing adolescents below 18 years of age

Side effects

Diarrhoea (5.86%) - most common adverse reaction, generally mild to moderate (eMC §4.8)
Nausea (5.47%) - common; also vomiting, abdominal pain, dyspepsia, dry mouth, flatulence, constipation
Hypertransaminasaemia (2.85%) - common; blood alkaline phosphatase increased, gamma-glutamyltransferase increased and blood albumin decreased are uncommon
Headache (common); peripheral neuropathy including paraesthesia and hypoaesthesia, dizziness, dysgeusia, insomnia, hallucination, anxiety and confusional state (uncommon)
Infusion site reaction, pruritus, fungal infection and hyperglycaemia (common); Clostridioides difficile infection, hypersensitivity, tendonitis, arthralgia, myalgia, hypoglycaemia, anaemia, leukopenia, thrombocytopenia and renal impairment (uncommon)

Interactions

The eMC §4.5 interaction section was not captured in this bundle - clinician to review it in the SPC. The interactions below are from the US labelling (openFDA, Baxdela §7.1) and are provided as a cross-check only
Oral chelation agents - antacids containing aluminium or magnesium, sucralfate, metal cations such as iron, multivitamins containing iron or zinc, and formulations containing divalent/trivalent cations such as didanosine buffered tablets for oral suspension or paediatric powder for oral solution - substantially interfere with absorption of oral delafloxacin; give the tablet at least 2 hours before or 6 hours after these agents (US §7.1)
Intravenous delafloxacin must not be co-administered with any solution containing multivalent cations (e.g. magnesium, calcium) through the same intravenous line, and must not be co-infused with other medications (US §7.1 / §2.1)
Concurrent systemic corticosteroids may increase the risk of aortic aneurysm, dissection and their rupture with fluoroquinolones (eMC §4.4)

Clinical monograph

How it works

It inhibits the bacterial enzymes DNA gyrase and topoisomerase IV, blocking DNA replication and transcription and leading to bacterial cell death.

Prescribing in practice

Fluoroquinolones carry a risk of disabling and potentially long-lasting or irreversible adverse effects on tendons, muscles, joints, and the nervous system, so MHRA advises restricting use to situations where other antibacterials are unsuitable.
Tendon rupture and aortic aneurysm or dissection have been associated with fluoroquinolones, with greater risk in older patients and those on corticosteroids.
They may prolong the QT interval and can cause central nervous system effects including seizures.

Monitoring

Monitor for tendon, musculoskeletal, neurological, and psychiatric adverse effects, and stop treatment at the first sign of a serious reaction.

Counselling the patient

Stop the medicine and seek advice immediately if you develop tendon pain or swelling, or new neurological or psychiatric symptoms.
Avoid taking indigestion remedies, or iron and other mineral supplements, around the same time as the dose.

Evidence & guidelines

MHRA safety guidance on systemic fluoroquinolones underpins the restricted-use recommendation, with efficacy demonstrated in randomised trials for skin and respiratory infections.

Reference: MHRA Drug Safety Update; BSAC; UKHSA AMR; SmPC; 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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