About nalidixic acid

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.

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