Sulfapyridine (Oral)

Although there are several possible uses for sulfapyridine, it is most often prescribed as a treatment for patients suffering from the skin disease known as dermatitis herpetiformis.


The condition for which sulfapyridine is most commonly prescribed is dermatitis herpetiformis, which is a skin disease that primarily afflicts adolescents and younger adults. It is characterized by the systematic appearance of extremely irritating and sometimes painful rashes on the shoulder blades, buttocks, elbows, and the reverse side of thighs. It is sometimes necessary to take the drug for up to six months in order for the symptoms to be completely cleared up, and to prevent the recurrence of symptoms. Since the disease does not generally occur in children, sulfapyridine is generally used only by adult patients, and doctors generally want to monitor results closely to determine its effectiveness.

Condition Treated

Type of Medicine

  • Dermatitis herpetiformis suppressant

Side Effects

There are times when any medication, including sulfapyridine, can produce unwanted effects in the patient in addition to the positive benefits that it brings. It should be understood that any side effects which might appear as a result of using sulfapyridine are likely to be different in all patients, because everyone's body chemistry reacts differently to specific medications. Therefore, the side effects listed below could be very mild in their impact, or they could be more severe, and if any of them appear during your program of treatment with sulfapyridine, you should contact your doctor and discuss what you are experiencing.

  • fevers
  • persistent headaches
  • itchiness or rashes on the skin
  • continuing aches in the muscles and joints
  • unexplained bleeding or bruising
  • a yellowish tinge to the eyes or the skin
  • difficulty in swallowing
  • sore throat that does not go away
  • skin which exhibits peeling, loosening, blistering, or noticeable redness
  • unexplained weakness and/or fatigue
  • swelling in the forward part of the neck
  • persistent discomfort or burning sensation when urinating
  • traces of blood in the urine
  • pain in the lower back which persists beyond any period of exertion
  • extreme sensitivity of your skin to ordinary sunlight.

There are some other side effects which have not been listed above and do not require medical attention at all. These kinds of side effects will generally appear briefly and simply fade away within a day or two, as your body adjusts to the medication being used.

For those side effects which persist and are included in the above listing, you should always mention these to your family doctor in case they are indicators of a serious reaction to sulfapyridine. In some cases, your doctor will be able to suggest ways of reducing the effects of any discomfort you may experience, or of treating the side effect so that it's eliminated entirely.

Side effects which you should immediately consult with your doctor about include persistent diarrhea, an ongoing loss of appetite, and severe nausea or vomiting. If any of these side effects appear during your treatment program, it is possible that your doctor may want to discontinue usage of sulfapyridine, or to alter the dosage which has been prescribed.


As with most medications, dosages of sulfapyridine in adults will differ based on concurrent usage of other medications, levels of tolerance, severity of the existing condition, and other factors. The dosages listed below should be considered standard or average dosages, and these are more guidelines than anything else, certainly not to be used in favor of your doctor's recommended dosages.

It's also true that the medicine that you take on any given day will be closely related to the strength of the medication itself, as well as the number of doses which are prescribed for that day. The duration of any program of treatment with sulfapyridine will be dependent on the precise condition being treated, in addition to the effectiveness which is exhibited during the program.

The condition most commonly treated by sulfapyridine is dermatitis herpetiformis, and for adults and adolescents, the most common dosage falls in a range between 250 mg and 1 g, to be administered four times each day, with dosages being equally spaced out throughout the day.

This dosage strategy should be followed until noticeable improvement occurs, and then the dosage can be reduced by somewhere between 250 and 500 mg every two or three days. Once the dosage has been reduced to this point, there is only a single dosage which should be administered daily, and by this time improvement should have progressed so that there are no observable symptoms.

Still, it is highly recommended that all prescribed medication is used up completely, even if improvement is detectable long before the end of a program of treatment. If you should miss a regularly scheduled dosage of sulfapyridine, just skip that dosage and wait for the next scheduled one. It is never advisable to double up on dosages, even if you feel that your symptoms are becoming worse. In situations like that, make sure to discuss it with your doctor completely, so that he can either increase the dosage you are on, or he can possibly consider switching you over to an alternative medication.


Interactions between sulfapyridine and other drugs are possible, although there are relatively few of them, and these interactions tend to be on the milder side.

  • Bone marrow depressants - when using sulfapyridine in conjunction with any kind of bone marrow depressants, it is possible to exacerbate the thrombocytopenic and/or leukopenia effects of the bone marrow medications. If it is still deemed worthwhile to use sulfapyridine in conjunction with these types of medications, there should be close monitoring to detect any manifestations of myelotoxic effect
  • medications being used for the treatment of seizures or convulsions
  • any kinds of medications used as blood thinners to inhibit the process of coagulation
  • some types of antidiabetic agents - metabolism could possibly be inhibited by the sulfonamides in sulfapyridine, which can enhance the potential for toxicity. If any of these kinds of medications are used in conjunction with sulfapyridine, it may be advisable to alter dosages both during and after the program of treatment
  • hemolytics - usage of any kind of drugs in this class can increase the possibility for the development of various toxic side effects
  • hepatotoxic medications - when used in conjunction with sulfapyridine, any drugs in this class may have the effect of increasing the occurrence of hepatotoxicity. This makes it advisable for any current liver patients, or patients with a past history of liver problems, to either not use sulfapyridine concurrently, or to be closely monitored for any warning signs of increased toxicity.
  • methotrexate/phenylbutazone/sulfinpyrazone - any of these three drugs when used in tandem with sulfapyridine can encourage plasma displacement from protein-binding sites in the body. Phenylbutazone has also been known to have a direct influence on the effectiveness of sulfonamides
  • bentiromide - any patient being treated with sulfapyridine at the same time as undergoing a bentiromide test period will cause the test results to be invalidated, because the sulfonamides will be metabolized, and will skew test results. If a bentiromide test is planned, it is recommended that treatment with sulfapyridine is discontinued at least three days prior to the test.


Patients who are involved with a program of treatment which includes sulfapyridine should be aware of some of the warnings and precautions which are advised by knowledgeable scientists and medical personnel. First among these are allergic reactions. Anyone who is allergic to sulfonamides, or to furosemide, sulfonylureas, thiazide diuretics, or carbonic anhydrase inhibitors could possibly be allergic to sulfapyradine as well.

Since allergic reactions can vary in severity between very mild and fairly extreme, any suspicion of being allergic should be discussed with the family doctor carefully. With regard to allergic reactions and all other precautions and warnings as well, the benefits derived from taking sulfapyridine should always be weighed against any negative reactions it produces in the patient.

Another fairly serious precaution which should be considered is the carcinogenic aspect of sulfonamides. Research has shown that long-term usage of sulfapyridine in laboratory rats has produced a high incidence of thyroid malignancies. Although it is apparent that rats are more susceptible to the potential effects of sulfonamides than other animal species, including humans, this is still something worth considering, because of the gravity of the potential effects which might be produced.

There are several warnings which should be observed in conjunction with reproduction in male and female humans. Sulfapyridine has been associated with causing infertility and oligospermia in males, rendering them incapable of reproducing. Although inadequate research exists to state any effects on females with certainty, it is known that sulfapyridine does cross through the placenta, and that means there is at least the possibility of causing kernicterus in the unborn infant.

For this reason, it is strongly recommended that women who are pregnant or are considering becoming pregnant, should not use sulfapyridine either before or after pregnancy. Women who are breastfeeding or plan to breastfeed, should discuss this with the family doctor, since sulfapyridine is a substance which is known to be present in breast milk, and in fairly significant concentrations. This makes it very likely that the drug would be passed on to an infant, with the possibility of developing kernicterus while nursing.

Sulfapyridine is not recommended for children less than the age of 18, and since this age group seldom develops dermatitis herpetiformis anyway, there is virtually no reason why the drug would be prescribed for youngsters.

There is no information available from research which indicates any kind of danger or precautions which should be specifically observed by geriatric patients, so any risks to older age groups are no better or worse than for all other age groups.

There are some known impacts which have been reported by patients using sulfapyridine on the mouth and dental structure. In some patients, there has been an increased incidence of specific microbial infections which are traceable to the thrombocytopenic effects and the leukopenia effects of using sulfapyridine.

A patient in whom leukopenia or thrombocytopenia begins to develop, should avoid having any dental work done, until blood counts have been restored to a more satisfactory level. All patients using sulfapyridine should be well briefed on how to conduct proper oral hygiene, specifically with regard to all the normal actions of using toothbrushes, toothpicks, and dental floss. Improper usage of any or all of these materials can trigger unwanted dental reactions in patients using sulfapyridine.


Sulfapyridine should always be stored in a sealed container, out of the reach of children and pets, and away from direct sunlight. It should be kept at room temperature, in a location not subject to extremes of heat or cold, and where there is no excess humidity. Any unused or expired sulfapyridine should be disposed of properly, and not used by the patient, nor transferred to any other individual who may be suffering from a skin disorder.


One of the best medications for the treatment of dermatitis herpetiformis is sulfapyridine, which acts to reduce the symptoms of swelling, rashes, and outbreaks of inflammation on the body. It is generally effective for this kind of treatment, and has few interactions with other drugs. It can produce some mild side effects in patients using the drug, and there are a couple which are more serious and need to be monitored closely. Some patients may experience symptom relief in a relatively short span of treatment, while others require a full six months before noticeable improvement occurs.

Last Reviewed:
December 24, 2017
Last Updated:
April 05, 2018
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