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Sulfisoxazole Side Effects

For the Consumer

Applies to sulfisoxazole: oral suspension, oral syrup, oral tablet

Along with its needed effects, sulfisoxazole 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 while taking sulfisoxazole:


  • Anxiety
  • blurred vision
  • changes in menstrual periods
  • chills
  • cold sweats
  • coma
  • confusion
  • cool, pale skin
  • decreased sexual ability in males
  • depression
  • dizziness
  • dry, puffy skin
  • fast heartbeat
  • feeling cold
  • headache
  • increased hunger
  • nausea
  • nervousness
  • nightmares
  • seizures
  • shakiness
  • slurred speech
  • swelling of the front part of the neck
  • unusual tiredness or weakness
  • weight gain

Incidence Not Known

  • Abdominal or stomach pain, cramps, or tenderness
  • agitation
  • back, leg, or stomach pains
  • bleeding gums
  • bleeding under the skin
  • blindness or vision changes
  • blistering, peeling, or loosening of the skin
  • bloating
  • bloody or cloudy urine
  • bloody, black, or tarry stools
  • bluish color of the fingernails, lips, skin, palms, or nail beds
  • burning of the face or mouth
  • burning, crawling, itching, numbness, painful, prickling, "pins and needles", or tingling feelings
  • change in the ability to see colors, especially blue or yellow
  • chest pain
  • chills
  • clay-colored stools
  • clumsiness or unsteadiness
  • constipation
  • continuing ringing or buzzing or other unexplained noise in the ears
  • cough or hoarseness
  • cracks in the skin
  • dark urine
  • decrease in frequency of urination
  • decrease in the amount of urine
  • diarrhea
  • diarrhea, watery and severe, which may also be bloody
  • difficult or painful urination
  • difficulty in passing urine (dribbling)
  • difficulty with breathing
  • difficulty with swallowing
  • dizziness or lightheadedness
  • drowsiness
  • enlarged salivary glands
  • fainting
  • fast, pounding, or irregular heartbeat or pulse
  • feeling of discomfort
  • feeling unusually cold
  • fever with or without chills
  • general body swelling
  • general feeling of discomfort or illness
  • general feeling of tiredness or weakness
  • hair loss
  • headache
  • hearing loss
  • hives or welts
  • hostility
  • increased sensitivity of the skin to sunlight
  • increased thirst
  • indigestion
  • inflammation of the joints
  • irritability
  • itching
  • joint or muscle pain
  • large, hive-like swelling on the face, eyelids, lips, tongue, throat, hands, legs, feet, or sex organs
  • lethargy
  • light-colored stools
  • loss of appetite and weight
  • loss of heat from the body
  • loss of strength or energy
  • lower back or side pain
  • muscle aches
  • muscle pain or weakness
  • muscle twitching
  • nosebleeds
  • not able to pass urine
  • pain
  • pain or burning while urinating
  • pains in the stomach, side, or abdomen, possibly radiating to the back
  • pale skin
  • pinpoint red or purple spots on the skin
  • puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue
  • rapid heart rate
  • rapid weight gain
  • rash
  • red skin lesions, often with a purple center
  • red, irritated eyes
  • red, swollen skin
  • redness of the white part of the eyes
  • redness, soreness or itching skin
  • scaly skin
  • severe sunburn
  • shakiness and unsteady walk
  • shivering
  • shortness of breath
  • skin rash
  • sore throat
  • soreness of the muscles
  • sores, ulcers, or white spots on the lips or in the mouth
  • sores, welting, or blisters
  • stupor
  • swelling around the eyes
  • swelling of face, ankles, hands, feet, or lower legs
  • swelling or inflammation of the mouth
  • swollen lymph glands
  • swollen or painful glands
  • thickening of bronchial secretions
  • tightness in the chest
  • troubled breathing
  • troubled breathing with exertion
  • unpleasant breath odor
  • unsteadiness, trembling, or other problems with muscle control or coordination
  • unusual bleeding or bruising
  • unusual weak feeling
  • unusual weight gain
  • unusual weight loss
  • upper right abdominal pain
  • vomiting
  • vomiting of blood or material that looks like coffee grounds
  • weakness in the hands or feet
  • weight loss
  • wheezing
  • yellow eyes or skin

Some side effects of sulfisoxazole 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

  • Confusion about identity, place, and time
  • difficulty with moving
  • excess air or gas in the stomach or intestines
  • fear
  • feeling of constant movement of self or surroundings
  • feeling that others are watching you or controlling your behavior
  • feeling that others can hear your thoughts
  • feeling, seeing, or hearing things that are not there
  • full feeling
  • lack of feeling or emotion
  • passing gas
  • redness, swelling, or soreness of the tongue
  • sensation of spinning
  • severe mood or mental changes
  • sleeplessness
  • trouble with sleeping
  • unable to sleep
  • uncaring
  • unusual behavior

For Healthcare Professionals

Applies to sulfisoxazole: compounding powder, oral suspension, oral tablet


In general, although not every side effect listed in the side effects section may have been reported with the use of sulfisoxazole, they have all been reported with the use of one or more sulfonamide compounds.

Sulfisoxazole was generally well tolerated. Less than 0.1% of patients experienced serious side effects from sulfisoxazole.[Ref]


Hypersensitivity side effects have included anaphylaxis, erythema multiforme (Stevens-Johnson syndrome), toxic epidermal necrolysis, angioedema, arteritis and vasculitis, serum sickness, conjunctival and scleral injection, generalized allergic reactions, and allergic myocarditis.[Ref]

The use of sulfonamide antibiotics is associated with large increases in the risk of Stevens-Johnson syndrome or toxic epidermal necrolysis, although these phenomena are rare as a whole.[Ref]


Dermatologic side effects have included exfoliative dermatitis, rash, pruritus, photosensitivity, periarteritis nodosa, systemic lupus erythematosus, and generalized skin eruptions.[Ref]


Hematologic side effects have included agranulocytosis, leukopenia, thrombocytopenia, aplastic anemia, purpura, hemolytic anemia, eosinophilia, clotting disorders including hypoprothrombinemia, hypofibrinogenemia, sulfhemoglobinemia, and methemoglobinemia.[Ref]


Hepatic side effects have included hepatitis, hepatocellular necrosis, and jaundice. Elevated liver-associated enzymes have been reported in patients with hepatitis. Rare cases of hepatic necrosis have been associated with some sulfonamides.[Ref]


Renal side effects have included elevated BUN and creatinine, acute renal failure, nephritis, and nephrosis with oliguria and anuria. The frequency of renal complications is lower with the more soluble sulfonamides, such as sulfisoxazole.[Ref]


Genitourinary side effects have included crystalluria, hematuria, and urinary retention.


Cardiovascular side effects have included tachycardia, palpitations, syncope, cyanosis, angioedema, arteritis, and vasculitis.


Gastrointestinal side effects have included pseudomembranous colitis, nausea, emesis, anorexia, abdominal pain, diarrhea, gastrointestinal hemorrhage, melena, flatulence, glossitis, stomatitis, enlarged salivary gland, and pancreatitis.

Pseudomembranous colitis has occurred during or after sulfisoxazole therapy.

Nervous system

Nervous system side effects have included headache, dizziness, peripheral neuritis, paresthesia, convulsions, drowsiness, hearing loss, insomnia, tinnitus, vertigo, ataxia, and intracranial hypertension.[Ref]


Psychiatric side effects have included psychosis, hallucination, disorientation, depression, anxiety, and apathy.


Other side effects have included edema (including periorbital), pyrexia, weakness, fatigue, lassitude, rigors, flushing, and chills.


Respiratory side effects have included cough, shortness of breath, pulmonary infiltrates, and pneumonitis.


Musculoskeletal side effects have included arthralgia and myalgia.


Endocrine side effects have been reported rarely in patients receiving sulfonamides and have included goiter development, diuresis, and hypoglycemia.


1. "Multum Information Services, Inc. Expert Review Panel"

2. Kounis GN, Kouni SA, Chiladakis JA, Kounis NG "Comment: Mesalamine-Associated Hypersensitivity Myocarditis in Ulcerative Colitis and the Kounis Syndrome (February)." Ann Pharmacother 43 (2009): 393-4

3. Flach A, Peterson J, Mathias T "Photosensitivity to topically applied sulfisoxazole ointment." Arch Ophthalmol 100 (1982): 1286-7

4. Flach A "Photosensitivity to sulfisoxazole ointment." Arch Ophthalmol 99 (1981): 609-10

5. Roujeau JC, Kelly JP, Naldi L, et al. "Medication use and the risk of Stevens-Johnson syndrome or toxic epidermal necrolysis." N Engl J Med 333 (1995): 1600-7

6. "Product Information. Gantrisin (sulfisoxazole)." Roche Laboratories, Nutley, NJ.

7. Boyer W, Lake C "Interaction of phenelzine and sulfisoxazole." Am J Psychiatry 140 (1983): 264-5

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some side effects may not be reported. You may report them to the FDA.