Health Guide

Nalidixic acid (By mouth)

Nalidixic Acid (nal-i-DIX-ik AS-id)

Treats urinary tract infections that are caused by bacteria. This medicine is a quinolone antibiotic.

Brand Name(s):

There may be other brand names for this medicine.

When This Medicine Should Not Be Used:

You should not use this medicine if you have had an allergic reaction to nalidixic acid or other quinolone antibiotics such as ciprofloxacin, gatifloxacin, levofloxacin, Ciloxan®, Cipro®, Levaquin®, or Tequin®. You should not use this medicine if you have porphyria or a seizure disorder, or if you are breast feeding. You should not use this medicine if you are using cancer medicine such as melphalan or other similar medicines. Do not give this medicine to a child under 3 months of age.

How to Use This Medicine:


  • Your doctor will tell you how much of this medicine to use and how often. Do not use more medicine or use it more often than your doctor tells you to.
  • Drink extra fluids so you will pass more urine while you are using this medicine. This will keep your kidneys working well and help prevent kidney problems.
  • You may take this medicine with or without food.
  • Keep using this medicine for the full treatment time, even if you feel better after the first few doses. Your infection may not clear up if you stop using the medicine too soon.

If a dose is missed:

  • If you miss a dose or forget to use your medicine, use it as soon as you can. If it is almost time for your next dose, wait until then to use the medicine and skip the missed dose. Do not use extra medicine to make up for a missed dose.

How to Store and Dispose of This Medicine:

  • Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light.
  • Ask your pharmacist, doctor, or health caregiver about the best way to dispose of any leftover medicine after you have finished your treatment. You will also need to throw away old medicine after the expiration date has passed.
  • Keep all medicine away from children and never share your medicine with anyone.

Drugs and Foods to Avoid:

Ask your doctor or pharmacist before using any other medicine, including over-the-counter medicines, vitamins, and herbal products.

  • Make sure your doctor knows if you are also using steroid medicine such as cortisone, dexamethasone, prednisone, prednisolone, or Medrol®.
  • Make sure your doctor knows if you are also using cyclosporine (Sandimmune®, Neoral®), probenecid (Benemid®), theophylline, or a blood thinner such as warfarin (Coumadin®).
  • Make sure your doctor knows if you are using medicines to treat infections such as chloramphenicol, erythromycin (Ery-tab®,) nitrofurantoin, or tetracycline. Tell your doctor if you are using medicine for depression such as amitriptyline, imipramine, Norpramin®, or Vivactil®.
  • Tell your doctor if you are also using didanosine (Videx®), sucralfate (Carafate®), antacids that contain magnesium or aluminum (such as Maalox®), or multivitamins with iron or zinc. You should take these medicines at least 2 hours before or 2 hours after you take nalidixic acid.
  • Make sure your doctor knows if you are using medicines to treat abnormal heart rhythm such as amiodarone (Cordarone®), bretylium, disopyramide (Norpace®), quinidine (Cardioquin®, Quinaglute®, Quinidex®), ibutilide (Corvert®), procainamide (Procan®, Procanbid®, Pronestyl®), or sotalol (Betapace®).
  • Avoid caffeine (coffee, soda, chocolate) while you are using this medicine. Nalidixic acid may cause caffeine to stay in your body longer than usual.

Warnings While Using This Medicine:

  • Make sure your doctor knows if you are pregnant or breast feeding.
  • Make sure your doctor knows if you have a brain disease, heart disease, kidney disease, or liver disease.
  • This medicine may make you dizzy. Avoid driving, using machines, or doing anything else that could be dangerous if you are not alert.
  • Your doctor will need to check your blood or urine at regular visits while you are using this medicine. Be sure to keep all appointments.
  • If you have severe diarrhea, ask your doctor before taking any medicine to stop the diarrhea.
  • This medicine may make your skin more sensitive to sunlight. Use a sunscreen when you are outdoors. Avoid sunlamps and tanning beds.
  • Make sure any doctor or dentist who treats you knows that you are using this medicine. This medicine may affect the results of certain medical tests.
  • Your doctor will need to check your progress at regular visits while you are using this medicine. Be sure to keep all appointments.
  • Use this medicine only to treat the infection your doctor has prescribed it for. Do not use this medicine for any infection that has not been checked by your doctor.
  • Your tendons may be more easily injured while you are using this medicine. This risk of tendon injury may be greater in children. Call your doctor if you have pain or swelling in your knee, ankle, shoulder, elbow, hand, or wrist. You may need to stop using this medicine.
  • If you have a tendon injury while using this medicine, avoid exercising until after you have finished the medicine.

Possible Side Effects While Using This Medicine:

Call your doctor right away if you notice any of these side effects:

  • Allergic reaction: Itching or hives, swelling in your face or hands, swelling or tingling in your mouth or throat, chest tightness, trouble breathing.
  • Blistering, peeling, or red skin rash.
  • Drowsiness, headache, or dizziness.
  • Diarrhea, stomach pain, or bloody stools.
  • Muscle pain, tenderness, or weakness.
  • Numbness, tingling, or burning pain in your hands, arms, legs, or feet.
  • Tremors or seizures.
  • Unusual bleeding, bruising, or weakness.
  • Yellowing of your skin or the whites of your eyes.

If you notice these less serious side effects, talk with your doctor:

  • Blurred vision, eyes more sensitive to light.
  • Feeling nervous, restless, anxious, or agitated.
  • Mild joint pain or stiffness in your joint.
  • Mild nausea or vomiting.

If you notice other side effects that you think are caused by this medicine, tell your doctor

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088

Last Updated: 6/12/2013
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