Ciprofloxacin: uses, serious side effects and cautions

Ciprofloxacin is a broad-spectrum antibiotic. The NHS lists urinary tract infections, chest infections and pneumonia, skin and bone infections, sexually transmitted infections, eye and ear infections, preventing meningitis in people exposed to it, and infections resistant to other treatments.

The NHS is direct about its place in modern prescribing: the tablets and liquid are used only when no other antibiotics are suitable, because of the risk of serious and long-term side effects, and it is used less often than alternatives. Eye and ear drops carry less of this risk.

For tablets and liquid the NHS gives a usual amount of 250 mg to 750 mg twice a day, with a single dose for some infections and lower amounts for children and people with kidney problems. Eye drops are used as 1 to 2 drops four times a day and ear drops up to 5 drops twice a day.

You can take tablets with or without food, but avoid dairy products such as milk, cheese and yoghurt around the dose because they affect how the medicine works. Calcium-fortified drinks count too; wait at least 2 hours.

Courses are commonly 1 to 2 weeks and sometimes up to 3 months. Finish the course, swallow tablets whole and use the supplied measure for liquid.

• Missed dose: take it when you remember unless the next is near; do not double up.

• Call NHS 111 if a child exceeds their dose, you take 2 or more extra doses, or you get side effects such as nausea, diarrhoea or palpitations.

The NHS lists many conditions to mention: abdominal aortic aneurysm, congenital heart or heart valve disease, rheumatoid arthritis, Behcet's disease, Marfan syndrome, epilepsy, kidney disease, diabetes, high blood pressure, mental health conditions, tendon problems and connective tissue disorders.

Also tell the prescriber about earlier allergic reactions, previous serious side effects with antibiotics, diarrhoea after antibiotics and blood sugar management concerns.

Common effects include nausea, diarrhoea, a bad taste, and, with drops, stinging or grittiness in the eye or white specks on the eye surface. Eat simple meals and take the dose after food for nausea.

The NHS says some people develop serious side effects during treatment or months afterwards, and they can occasionally persist for a long time, which is why it is not prescribed for more than 3 months continuously.

• Stop and contact a doctor or NHS 111 for muscle weakness, joint pain or tendon swelling, especially in the ankles or calves.

• Stop and seek advice for numbness, tingling or pins and needles, ringing in the ears, vision or taste changes, or palpitations and sudden breathlessness.

• Mood or behaviour changes, severe tiredness, anxiety, low mood or depression are also reasons to stop and call.

• Call 999 for suicidal thoughts, severe stomach, chest or back pain, seizures, or anaphylaxis.

Antacids reduce absorption, so take ciprofloxacin at least 2 hours before them or at least 4 hours after. Iron, calcium and zinc supplements need a gap of at least 2 hours.

The NHS also names methotrexate, phenytoin, steroids such as prednisolone, theophylline and aminophylline, tizanidine and warfarin. Tell the prescriber about every medicine and supplement you take.

Tablets and liquid are not generally recommended in pregnancy, although ear and eye drops are considered acceptable, and your doctor will usually suggest another antibiotic. Breastfeeding may be possible if your baby is healthy, because little enters breast milk, though other medicines may be preferable.

Alcohol is safe with it according to the NHS. It may cause tiredness or reduced alertness, so avoid driving if you feel affected, after eye drops until vision clears, or if an ear infection affects balance. Suspected side effects can be reported to Yellow Card.