Sulfonamides or sulfa medicines are used to treat infections. They will not work for colds, flu, or other virus infections.
Sulfonamides are available only with your doctor's prescription.
Tell your doctor if you have ever had any unusual or allergic reaction to medicines in this group 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.
Sulfonamides should not be given to infants under 2 months of age unless directed by the child's doctor, because they may cause unwanted effects.
Elderly people are especially sensitive to the effects of sulfonamides. Severe skin problems and blood problems may be more likely to occur in the elderly. These problems may also be more likely to occur in patients who are taking diuretics (water pills) along with this medicine.
Studies have not been done in pregnant women. However, studies in mice, rats, and rabbits have shown that some sulfonamides cause birth defects, including cleft palate and bone problems. Sulfonamides are not recommended for use at the time of labor and delivery. These medicines may cause unwanted effects in the baby.
Sulfonamides pass into the breast milk. This medicine is not recommended for use during breast-feeding. It may cause liver problems, anemia, and other unwanted effects in nursing babies, especially those with glucose-6-phosphate dehydrogenase (G6PD) deficiency.
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 any of these medicines, 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 medicines in this class with any of the following medicines is not recommended. Your doctor may decide not to treat you with a medication in this class or change some of the other medicines you take.
Using medicines in this class 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.
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. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.
Using medicines in this class with any of the following is usually not recommended, but may be unavoidable in some cases. If used together, your doctor may change the dose or how often you use your medicine, or give you special instructions about the use of food, alcohol, or tobacco.
Other medical problems
The presence of other medical problems may affect the use of medicines in this class. Make sure you tell your doctor if you have any other medical problems, especially:
Sulfonamides should not be given to infants less than 2 months of age unless directed by the patient's doctor because sulfonamides may cause serious unwanted effects.
Sulfonamides are best taken with a full glass (8 ounces) of water. Several additional glasses of water should be taken every day, unless otherwise directed by your doctor. Drinking extra water will help to prevent some unwanted effects of sulfonamides.
For patients taking the oral liquid form of this medicine:
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. If you stop taking this medicine too soon, your symptoms may return.
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 day and night. If you need help in planning the best times to take your medicine, check with your health care professional.
The dose medicines in this class 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 these medicines. 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.
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.
Keep out of the reach of children.
Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Keep from freezing.
Do not keep outdated medicine or medicine no longer needed.
It is very important that your doctor check your progress at regular visits. This medicine may cause blood problems, especially if it is taken for a long time.
If your symptoms do not improve within a few days, or if they become worse, check with your doctor.
Sulfonamides may cause blood problems. These problems may result in a greater chance of certain infections, slow healing, and bleeding of the gums. Therefore, you should be careful when using regular toothbrushes, dental floss, and toothpicks. Dental work should be delayed until your blood counts have returned to normal. Check with your medical doctor or dentist if you have any questions about proper oral hygiene (mouth care) during treatment.
Sulfonamides 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:
If you have a severe reaction from the sun, check with your doctor.
This medicine may also cause some people to become dizzy. 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. If this reaction is especially bothersome, check with your doctor.
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:
Some of the above side effects (severe abdominal or stomach cramps and pain, and watery and severe diarrhea, which may also be bloody) may also occur up to several weeks after you stop taking any of these medicines.
Check with your doctor as soon as possible if any of the following side effects occur:
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:
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.