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Nalidixic acid

  • Nalidixic acid is used for the treatment of urinary tract infections.
  • It is important to complete the course you have been given unless you are told to stop. This is to prevent the infection from coming back.
  • The most common side-effects are feeling sick, diarrhoea, dizziness and headache.

About nalidixic acid

Type of medicineQuinolone antibiotic
Used forTreatment of urinary tract infections such as cystitis
Available asOral suspension

Nalidixic acid is used to treat bacterial infections of the urinary system. It works by killing the bacteria which cause the infection.

Before taking nalidixic acid

Before taking nalidixic acid make sure your doctor or pharmacist knows:

  • If you are pregnant, trying for a baby or breast-feeding.
  • If you have liver or kidney problems.
  • If you have epilepsy or any other condition that causes convulsions.
  • If you have myasthenia gravis (a muscle weakening disease).
  • If you have glucose 6-phosphate dehydrogenase (G6PD) deficiency.
  • If you have porphyria (a rare blood disorder).
  • If you are taking other medicines, including those available to buy without a prescription, herbal and complementary medicines.
  • If you have ever had an allergic reaction to this or any other medicine.

How to take nalidixic acid

  • Before starting this treatment, read the manufacturer's printed information leaflet from inside the pack.
  • Take nalidixic acid exactly as your doctor has told you.
  • Spread your doses out evenly throughout the day.
  • Keep taking this antibiotic until the course is finished unless you are told to stop. This is important in order to prevent the infection from coming back.
  • If you forget to take a dose, take it as soon as you remember unless it is nearly time for your next dose, in which case leave out the missed dose. Do not take two doses together to make up for a forgotten dose.

Getting the most from your treatment

  • Keep any regular appointments with your doctor so your progress can be monitored. If you are taking nalidixic acid for more than 2 weeks, your doctor will probably want you to have some blood tests.
  • If you buy any medicines, particularly anti-inflammatory painkillers, check with a pharmacist that they are safe to take with this antibiotic.
  • Nalidixic acid may cause your skin to become more sensitive to sunlight than normal. Protect your skin from sunlight even on bright but cloudy days. Do not use sunbeds.
  • If you are using oral combined hormonal contraception (the 'pill'), additional contraceptive precautions such as condoms are not required during a course of this antibiotic unless you are sick or have diarrhoea. If you need further advice, speak with your doctor or pharmacist.
  • If you are having any urine tests, tell the person doing the testing that you are taking nalidixic acid. This is because this medicine affects some types of urine glucose measurements.
  • This antibiotic may stop the oral typhoid vaccine from working. If you are having any vaccinations, make sure the person treating you knows that you are taking this medicine.
  • If you still feel unwell after completing your course of this antibiotic, make another appointment to see your doctor.
  • Some people develop thrush (redness and itching in the mouth or vagina) after taking a course of antibiotics. If you think you have thrush, speak with your doctor or pharmacist for advice.

Can nalidixic acid cause problems?

Along with their useful effects, most medicines can cause unwanted side-effects although not everyone experiences them. These usually improve as your body adjusts to the new medicine, but speak with your doctor or pharmacist if any of the following side-effects continue or become troublesome.

Common side-effectsWhat can I do if I experience this
Feeling or being sick, indigestion, stomach acheEat little and often. Stick to simple or bland foods
DiarrhoeaDrink plenty of water to replace lost fluids. If the diarrhoea is severe or continues to be a problem, speak with your pharmacist or doctor
HeadacheAsk your pharmacist to recommend a suitable painkiller. If the headache continues, speak with your doctor
DizzinessIf you are affected by this, make sure your reactions are normal before you drive or operate machinery

Important: If you develop any of the following rare symptoms, contact your doctor for advice straight away:

  • Swelling of your tongue, mouth, or face, or any problems with your breathing.
  • A severe rash.
  • Pain or inflammation in your joints (particularly in your hips, knees or ankles).

If you experience any other symptoms which you think may be due to this medicine, speak with your doctor or pharmacist for advice.

How to store nalidixic acid

  • Keep all medicines out of the reach and sight of children.
  • Store in a cool, dry place, away from direct heat and light.

Important information about all medicines


  • Never take more than the prescribed dose. If you suspect that you or someone else has taken an overdose of this medicine go to the accident and emergency department of your local hospital at once. Take the container with you, even if it is empty.
  • If you are having an operation or any dental treatment, tell the person carrying out the treatment which medicines you are taking.
  • This medicine is for you. Never give it to other people even if their condition appears to be the same as yours.
  • Never keep out of date or unwanted medicines. Take them to your local pharmacy which will dispose of them for you.
  • If you have any questions about this medicine ask your pharmacist.

References

Comprehensive patient resources are available at www.patient.co.uk
© EMIS 2011DocID: 3295DocRef: dils2225Last Reviewed: 14 Apr 2011Version: 24
For the planned review period see the Data Creation and Quality Control Process.
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