eg ciprofloxacin.

Broad spectrum antibiotics.

Block DNA synthesis by bacteria (uniquely among antibiotics).

Good against gram negatives, including Salmonella, Shigella, Neisseria, Pseudomonas (one of the few oral antipseudomonals).

Good intracellular penetration so active against organisms such as Chlamydia, Mycoplasma, Legionella and some Mycobacteria.

Good tissue penetration including central nervous system. 80% of orally administered drug is bioavailable so the IV route is only used when absorption impaired.

But no anti-anaerobic activity, and not very good against common gram positives eg Pneumococcus, Enterococcus, Staphylococcus (in fact, use is associated with MRSA). The newer types (Gatifloxacin, Moxifloxacin, Levofloxacin) have better gram positive activity but would still not be your first line choice, and have less anti-pseudomonal activity.

Not licensed under 1yr.

Only contraindication is previous tendon problem caused by it!

Adverse Effects:

• Disabling, long-lasting (even irreversible) musculoskeletal and neurological problems reported, v rarely. So only use for severe infections, unless no other antibiotic appropriate. And stop ASAP if symptoms (muscle pain, joint pain, weakness, neuropathy etc)
• Seizures (+/- predisposing condition)
• Tendonitis – rupture can occur within 48hrs of starting, but can also be months later! Steroids at same time may increase risk, as may renal impairment and solid organ transplants
• Arthropathy in immature animals – so avoided in children (except Nalidixic acid) unless extenuating circumstances (only reversible musculoskeletal symptoms have been reported). Arthropathy occurs in CF anyway.
• Can prolong QT
• Photosensitivity
• Valve regurgitation – so caution if preceding valve disease or other risk factor eg connective tissue disorder (Ehlers-Danlos, Marfans), hypertension (!), Turners (!)