Description and Brand Names

Drug information provided by: Merative, Micromedex®

US Brand Name

  1. Gantrisin Pediatric
  2. Truxazole


Sulfisoxazole is used to treat or prevent infections in many different parts of the body. It belongs to the group of medicines known as sulfonamide antibiotics. It works by preventing the growth of bacteria. However, this medicine will not work for colds, flu, or other virus infections.

This medicine is available only with your doctor's prescription.

Before Using

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 this medicine, the following should be considered:


Tell your doctor if you have ever had any unusual or allergic reaction to this medicine or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.


Because of sulfisoxazole's toxicity, use in infants younger than 2 months of age is not recommended.


No information is available on the relationship of age to the effects of sulfisoxazole in geriatric patients. However, elderly patients are more likely to have age-related kidney and liver problems, which may require caution in patients receiving sulfadiazine.


Studies in women suggest that this medication poses minimal risk to the infant when used during breastfeeding.

Drug Interactions

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 this medicine, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.

Using this medicine with any of the following medicines is not recommended. Your doctor may decide not to treat you with this medication or change some of the other medicines you take.

  • Methenamine

Using this medicine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

  • Methotrexate
  • Porfimer
  • Warfarin

Using this medicine with any of the following medicines may cause an increased risk of certain side effects, but using both drugs may be the best treatment for you. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

  • Acetohexamide
  • Aminolevulinic Acid

Other Interactions

Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. Discuss with your healthcare professional the use of your medicine with food, alcohol, or tobacco.

Other Medical Problems

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

  • Asthma or
  • Blood problems (e.g., agranulocytosis, aplastic anemia) or
  • Glucose-6-phosphate dehydrogenase (G6PD) deficiency (an enzyme problem) or
  • Kidney disease or
  • Liver disease—Use with caution. May have an increased chance of side effects.

Proper Use

This medicine should not be given to infants younger than 2 months of age unless directed by your child's doctor. Sulfisoxazole may cause serious unwanted effects in this age group.

Take this medicine with a full glass (8 ounces) of water. Several additional glasses of water should be taken during the day, unless otherwise directed by your doctor. Drinking extra water will help to prevent some unwanted effects.

This medicine works best when there is a constant amount in the blood or urine. To help keep the amount constant, do not miss any doses. Also, it is best to take the doses at evenly spaced times during the day. If you need help in planning the best times to take your medicine, check with your doctor.

To help clear up your infection completely, keep using this medicine for the full treatment time, even if you feel better after the first few doses. If you stop taking this medicine too soon, your symptoms may return.

Shake the oral suspension well before each use. Measure the medicine with a marked measuring spoon, oral syringe, or medicine cup. The average household teaspoon may not hold the right amount of liquid.


The dose of this medicine 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 this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine 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 using the medicine.

  • For oral dosage form (suspension, tablets):
    • For treatment of infections:
      • Adults—4000 to 8000 milligrams (mg) per day, divided and given in 4 to 6 doses per day.
      • Children and infants 2 months of age and older—Dose is based on body weight and must be determined by your doctor. The starting dose is usually 75 milligrams (mg) per kilogram (kg) of body weight per day (mg/kg/day), divided and given in 4 to 6 doses per day. Your doctor may increase your dose to 150 mg/kg/day, but the total dose is usually not more than 6000 mg per day.
      • Infants younger than 2 months of age—Use is not recommended.

Missed Dose

If you 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.


Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Keep from freezing.

Keep out of the reach of children.

Do not keep outdated medicine or medicine no longer needed.

Ask your healthcare professional how you should dispose of any medicine you do not use.


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

Serious skin reactions can occur with this medicine. Stop using this medicine and check with your doctor right away if you have any of the following symptoms: a skin rash; blistering, peeling, or loosening of the skin; cough; diarrhea; itching; sores, ulcers, or white spots in the mouth or on the lips; or unusual tiredness or weakness.

Check with your doctor right away if you have fever; chills; joint or muscle pain; pale skin; pinpoint red or purple spots on the skin; shortness of breath; sore throat; pain in the upper stomach; or yellow eyes or skin. These may be symptoms of a serious blood problem.

Sulfisoxazole may cause diarrhea, and in some cases it can be severe. Do not take any medicine to treat diarrhea without checking first with your doctor. Diarrhea medicines may make the diarrhea worse or make it last longer. If mild diarrhea continues or gets worse, check with your doctor.

Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal or vitamin supplements.

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:


  1. Anxiety
  2. blurred vision
  3. changes in menstrual periods
  4. chills
  5. cold sweats
  6. coma
  7. confusion
  8. cool, pale skin
  9. decreased sexual ability in males
  10. depression
  11. dizziness
  12. dry, puffy skin
  13. fast heartbeat
  14. feeling cold
  15. headache
  16. increased hunger
  17. nausea
  18. nervousness
  19. nightmares
  20. seizures
  21. shakiness
  22. slurred speech
  23. swelling of the front part of the neck
  24. unusual tiredness or weakness
  25. weight gain

Incidence not known

  1. Abdominal or stomach pain, cramps, or tenderness
  2. agitation
  3. back, leg, or stomach pains
  4. bleeding gums
  5. bleeding under the skin
  6. blindness or vision changes
  7. blistering, peeling, or loosening of the skin
  8. bloating
  9. bloody or cloudy urine
  10. bloody, black, or tarry stools
  11. bluish color of the fingernails, lips, skin, palms, or nail beds
  12. burning of the face or mouth
  13. burning, crawling, itching, numbness, painful, prickling, "pins and needles", or tingling feelings
  14. change in the ability to see colors, especially blue or yellow
  15. chest pain
  16. chills
  17. clay-colored stools
  18. clumsiness or unsteadiness
  19. constipation
  20. continuing ringing or buzzing or other unexplained noise in the ears
  21. cough or hoarseness
  22. cracks in the skin
  23. dark urine
  24. decrease in frequency of urination
  25. decrease in the amount of urine
  26. diarrhea
  27. diarrhea, watery and severe, which may also be bloody
  28. difficult or painful urination
  29. difficulty in passing urine (dribbling)
  30. difficulty with breathing
  31. difficulty with swallowing
  32. dizziness or lightheadedness
  33. drowsiness
  34. enlarged salivary glands
  35. fainting
  36. fast, pounding, or irregular heartbeat or pulse
  37. feeling of discomfort
  38. feeling unusually cold
  39. fever with or without chills
  40. general body swelling
  41. general feeling of discomfort or illness
  42. general feeling of tiredness or weakness
  43. hair loss
  44. headache
  45. hearing loss
  46. hives or welts
  47. hostility
  48. increased sensitivity of the skin to sunlight
  49. increased thirst
  50. indigestion
  51. inflammation of the joints
  52. irritability
  53. itching
  54. joint or muscle pain
  55. large, hive-like swelling on the face, eyelids, lips, tongue, throat, hands, legs, feet, or sex organs
  56. lethargy
  57. light-colored stools
  58. loss of appetite and weight
  59. loss of heat from the body
  60. loss of strength or energy
  61. lower back or side pain
  62. muscle aches
  63. muscle pain or weakness
  64. muscle twitching
  65. nosebleeds
  66. not able to pass urine
  67. pain
  68. pain or burning while urinating
  69. pains in the stomach, side, or abdomen, possibly radiating to the back
  70. pale skin
  71. pinpoint red or purple spots on the skin
  72. puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue
  73. rapid heart rate
  74. rapid weight gain
  75. rash
  76. red skin lesions, often with a purple center
  77. red, irritated eyes
  78. red, swollen skin
  79. redness of the white part of the eyes
  80. redness, soreness or itching skin
  81. scaly skin
  82. severe sunburn
  83. shakiness and unsteady walk
  84. shivering
  85. shortness of breath
  86. skin rash
  87. sore throat
  88. soreness of the muscles
  89. sores, ulcers, or white spots on the lips or in the mouth
  90. sores, welting, or blisters
  91. stupor
  92. swelling around the eyes
  93. swelling of face, ankles, hands, feet, or lower legs
  94. swelling or inflammation of the mouth
  95. swollen lymph glands
  96. swollen or painful glands
  97. thickening of bronchial secretions
  98. tightness in the chest
  99. troubled breathing
  100. troubled breathing with exertion
  101. unpleasant breath odor
  102. unsteadiness, trembling, or other problems with muscle control or coordination
  103. unusual bleeding or bruising
  104. unusual weak feeling
  105. unusual weight gain
  106. unusual weight loss
  107. upper right abdominal pain
  108. vomiting
  109. vomiting of blood or material that looks like coffee grounds
  110. weakness in the hands or feet
  111. weight loss
  112. wheezing
  113. yellow eyes or skin

Some 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. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

Incidence not known

  1. Confusion about identity, place, and time
  2. difficulty with moving
  3. excess air or gas in the stomach or intestines
  4. fear
  5. feeling of constant movement of self or surroundings
  6. feeling that others are watching you or controlling your behavior
  7. feeling that others can hear your thoughts
  8. feeling, seeing, or hearing things that are not there
  9. full feeling
  10. lack of feeling or emotion
  11. passing gas
  12. redness, swelling, or soreness of the tongue
  13. sensation of spinning
  14. severe mood or mental changes
  15. sleeplessness
  16. trouble with sleeping
  17. unable to sleep
  18. uncaring
  19. unusual behavior

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

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