Generic name: sulfisoxazole [ sul-fi-SOX-a-zole ]
Drug class: Sulfonamides
Medically reviewed by Drugs.com. Last updated on May 5, 2023.
Uses for sulfisoxazole
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 sulfisoxazole
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.
Interactions with 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 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.
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.
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.
- Aminolevulinic Acid
Interactions with Food/Tobacco/Alcohol
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 of sulfisoxazole
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.
- For treatment of infections:
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.
Precautions while using sulfisoxazole
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 of sulfisoxazole
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:
- blurred vision
- changes in menstrual periods
- cold sweats
- cool, pale skin
- decreased sexual ability in males
- dry, puffy skin
- fast heartbeat
- feeling cold
- increased hunger
- 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
- back, leg, or stomach pains
- bleeding gums
- bleeding under the skin
- blindness or vision changes
- blistering, peeling, or loosening of the skin
- 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
- clay-colored stools
- clumsiness or unsteadiness
- 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, 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
- enlarged salivary glands
- 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
- hearing loss
- hives or welts
- increased sensitivity of the skin to sunlight
- increased thirst
- inflammation of the joints
- joint or muscle pain
- large, hive-like swelling on the face, eyelids, lips, tongue, throat, hands, legs, feet, or sex organs
- 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
- not able to pass urine
- 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
- 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
- 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
- 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 of blood or material that looks like coffee grounds
- weakness in the hands or feet
- weight loss
- 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
- Confusion about identity, place, and time
- difficulty with moving
- excess air or gas in the stomach or intestines
- 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
- trouble with sleeping
- unable to sleep
- 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.
More about sulfisoxazole
- Check interactions
- Compare alternatives
- Drug images
- Side effects
- Dosage information
- During pregnancy
- Drug class: sulfonamides
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