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Nalidixic Acid (Systemic)

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Nalidixic Acid (Systemic)

US Brand Names

• NegGram

Canadian Brand Names

• NegGram


Nalidixic (nal-i-DIX-ik) acid is used to treat infections of the urinary tract. It may be used for other problems as determined by your doctor.

Nalidixic acid is available only with your doctor's prescription, in the following dosage forms:


    • Suspension (U.S.)

    • Tablets (U.S. and Canada)

Special Considerations

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For nalidixic acid, the following should be considered:


Tell your doctor if you have ever had any unusual or allergic reaction to nalidixic acid, or to any related medicines such as alatrofloxacin or trovafloxacin (e.g., Trovan), cinoxacin (e.g., Cinobac), ciprofloxacin (e.g., Cipro), enoxacin (e.g., Penetrex), grepafloxacin (e.g., Raxar), levofloxacin (e.g., Levaquin), lomefloxacin (e.g., Maxaquin), norfloxacin (e.g., Noroxin), ofloxacin (e.g., Floxin), or sparfloxacin (e.g., Zagam). Also tell your health care professional if you are allergic to any other substances, such as foods, preservatives, or dyes.


Studies have not been done in humans. In animal studies, nalidixic acid causes birth defects and other problems at doses several times the human dose. However, use is not recommended during pregnancy, since nalidixic acid has been shown to cause bone development problems in young animals.


Nalidixic acid passes into breast milk. This medicine may cause blood problems in nursing babies with glucose-6-phosphate dehydrogenase (G6PD) deficiency. However, problems in other nursing babies have not been reported.


This medicine is not recommended for use in infants up to 3 months of age since nalidixic acid has been shown to cause bone development problems in young animals.

Caution is recommended in using nalidixic acid in children up to 18 years of age because nalidixic acid has been shown to cause bone development problems in young animals. However, your doctor my choose to use this medicine if other medicines cannot be used.


Caution is recommended in using nalidixic acid in children up to 18 years of age because nalidixic acid has been shown to cause bone development problems in young animals. However, your doctor my choose to use this medicine if other medicines cannot be used.

Older adults

This medicine has been studied in a limited number of elderly patients and has not been shown to cause different side effects or problems in older people than it does in younger adults.

Other medicines

Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking nalidixic acid, it is especially important that your health care professional know if you are taking any of the following:

    • Antacids, aluminum-, calcium-, or magnesium-containing, or

    • Iron supplements or

    • Multivitamin preparations, zinc-containing, or

    • Sucralfate-These medicines interfere with the absorption of nalidixic acid into the body and may decrease the effect of nalidixic acid

    • Anticoagulants (blood thinners)-Patients taking nalidixic acid with anticoagulants may have an increased chance of bleeding

    • Caffeine or

    • Cyclosporine (e.g., Neoral, Sandimmune) or

    • Theophylline (e.g., Theo-Dur)-Nalidixic acid may increase the amounts of these medicines in the blood and increase the chance of side effects from them

Other medical problems

The presence of other medical problems may affect the use of nalidixic acid. Make sure you tell your doctor if you have any other medical problems, especially:

    • Convulsive disorders, history of (seizures, epilepsy) or

    • Hardening of the arteries in the brain (severe)-Patients with these medical problems may have an increased chance of side effects affecting the nervous system

    • Glucose-6-phosphate dehydrogenase (G6PD) deficiency-Patients with G6PD deficiency may have an increased chance of side effects affecting the blood

    • Kidney disease (severe) or

    • Liver disease-Patients with liver disease or severe kidney disease may have an increase in side effects


Do not give this medicine to infants or children unless otherwise directed by your doctor. It has been shown to cause bone problems in young animals and may cause these problems in children.

Nalidixic acid is best taken with a full glass (8 ounces) of water on an empty stomach (either 1 hour before or 2 hours after meals). However, if this medicine causes nausea or upset stomach, it may be taken with food or milk. Several additional glasses of water should be taken every day, unless you are otherwise directed by your doctor.

For patients taking the oral liquid form of this medicine:

    • Use a specially marked measuring spoon or other device to measure each dose accurately. The average household teaspoon may not hold the right amount of liquid.

To help clear up your infection completely, keep taking this medicine for the full time of treatment , even if you begin to feel better after a few days. Do not miss any doses .


The dose of nalidixic acid will be different for different patients. Follow your doctor's orders or the directions on the label . The following information includes only the average doses of nalidixic acid. If your dose is different, do not change it unless your doctor tells you to do so.

The number of tablets or teaspoonfuls of suspension that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are taking nalidixic acid .

    • For oral dosage forms (oral suspension or tablets):

      o Adults and children 12 years of age and older: 1 gram (g) every six hours (four times a day) for one to two weeks to start; then, 500 milligrams (mg) every six hours.

      o Children 3 months to 12 years of age: The dose is based on body weight and must be determined by the doctor.

      o Infants up to 3 months of age: This medicine is not recommended in infants up to 3 months of age since nalidixic acid has been shown to cause bone problems in young animals.

Missed dose

If you do miss a dose of this medicine, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.


To store this medicine:

    • Keep out of the reach of children.

    • Store away from heat and direct light.

    • Do not store the tablet form of this medicine in the bathroom, near the kitchen sink, or in other damp places. Heat or moisture may cause the medicine to break down.

    • Keep the oral liquid form of this medicine from freezing.

    • Do not keep outdated medicine or medicine no longer needed. Be sure that any discarded medicine is out of the reach of children.


If you will be taking this medicine for more than 2 weeks, your doctor should check your progress at regular visits.

If your symptoms do not improve within 2 days, or if they become worse, check with your doctor.

If you are taking aluminum-, calcium-, or magnesium-containing antacids, iron supplements, zinc-containing multivitamins, or sucralfate, do not take them at the same time that you take this medicine. It is best to take these medicines at least 2 hours before or 2 hours after taking nalidixic acid.

This medicine may cause blurred vision or other vision problems. It may also cause some people to become dizzy, drowsy, or less alert than they are normally. Make sure you know how you react to this medicine before you drive, use machines, or do anything else that could be dangerous if you are dizzy or are not alert or able to see well . If these reactions are especially bothersome, check with your doctor.

This medicine may increase the central nervous system (CNS) stimulant effects of caffeine-containing foods or beverages such as chocolate, cocoa, tea, coffee, and cola drinks. Avoid eating or drinking large amounts of these foods or beverages while using this medicine. If you have questions about this, check with your doctor.

Nalidixic acid may cause your skin to be more sensitive to sunlight than it is normally. Exposure to sunlight, even for brief periods of time, may cause a skin rash, itching, redness or other discoloration of the skin, or a severe sunburn. When you begin taking this medicine:

    • Stay out of direct sunlight, especially between the hours of 10:00 a.m. and 3:00 p.m., if possible.

    • Wear protective clothing, including a hat. Also, wear sunglasses.

    • Apply a sun block product that has a skin protection factor (SPF) of at least 15. Some patients may require a product with a higher SPF number, especially if they have a fair complexion. If you have any questions about this, check with your health care professional.

    • Apply a sun block lipstick that has an SPF of at least 15 to protect your lips.

    • Do not use a sunlamp or tanning bed or booth.

If you have a severe reaction from the sun, check with your doctor .

For patients with diabetes:

    • This medicine may cause false test results with some urine glucose (sugar) tests . Check with your doctor before changing your diet or the dosage of your diabetes medicine.

Side Effects

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur:

More common

Skin rash.

Less common

Blurred or decreased vision; change in color vision; confusion; double vision; halos around lights; lightheadedness; overbright appearance of lights; restlessness; tremor.


Abdominal or stomach cramps or pain (severe); blistering, peeling, or loosening of skin and mucous membranes; bulging of fontanel (soft spot) on top of head of an infant; burning or tingling skin sensation; changes in facial skin color; chills; convulsions (seizures); dark or amber urine; diarrhea, watery and severe, which may also be bloody; fever; general feeling of discomfort or illness; hallucinations (seeing, hearing, or feeling things that are not there); headache (severe); hives; hoarseness; increased frequency of breathing; itching; joint pain, stiffness, or swelling; mood or other mental changes; nausea or vomiting; pale skin; pale stools; red skin lesions, often with a purple center; shortness of breath; sore throat; sudden trouble in swallowing or breathing; swelling of face, mouth, hands, or feet; unusual bleeding or bruising; unusual tiredness or weakness; visual changes; yellow eyes or skin.

Other side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. However, check with your doctor if any of the following side effects continue or are bothersome:

More common

Diarrhea; dizziness; feeling of constant movement of self or surroundings; drowsiness; headache; stomach pain; weakness.

Less common

Increased sensitivity of skin to sunlight.

Other side effects not listed above may also occur in some patients. If you notice any other effects, check with your doctor.

June 14, 1999

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