Sulfasalazine EC 500mg DR Tablets
It is used to treat rheumatoid arthritis.It is used to treat ulcerative colitis.It may be given to you for other reasons. Talk with the doctor.
Drug Class
Anti-inflammatory agent, Disease-modifying antirheumatic drug (DMARD)
Pharmacologic Class
Aminosalicylate, Sulfonamide
Pregnancy Category
B
FDA Approved
Jun 1950
DEA Schedule
Not Controlled
Overview
What is this medicine?
Sulfasalazine is a medication used to treat inflammatory bowel diseases like ulcerative colitis and certain types of arthritis, such as rheumatoid arthritis. It works by reducing inflammation in the body, especially in the gut. The delayed-release tablets are designed to pass through the stomach and release the medicine in the intestines, where it's needed most.
How to Use This Medicine
Taking Your Medication Correctly
To get the most benefit from your medication, follow your doctor's instructions carefully. Read all the information provided with your prescription and follow the instructions closely. Take your medication after meals to help minimize potential side effects. Swallow the tablets whole - do not chew, break, or crush them.
Continue taking your medication as directed by your doctor or healthcare provider, even if you start to feel better. It's essential to drink plenty of non-caffeinated liquids, unless your doctor advises you to limit your fluid intake.
Storing and Disposing of Your Medication
Store your medication at room temperature in a dry place, away from the bathroom. Keep all medications in a safe and secure location, out of the reach of children and pets. When your medication is no longer needed or has expired, dispose of it properly. Do not flush it down the toilet or pour it down the drain unless instructed to do so by your doctor or pharmacist. If you're unsure about the best way to dispose of your medication, consult with your pharmacist. You may also want to check if there are any drug take-back programs available in your area.
What to Do If You Miss a Dose
If you miss a dose, take it as soon as you remember. However, if it's close to the time for your next scheduled dose, skip the missed dose and resume your regular dosing schedule. Do not take two doses at the same time or take extra doses to make up for the missed one.
To get the most benefit from your medication, follow your doctor's instructions carefully. Read all the information provided with your prescription and follow the instructions closely. Take your medication after meals to help minimize potential side effects. Swallow the tablets whole - do not chew, break, or crush them.
Continue taking your medication as directed by your doctor or healthcare provider, even if you start to feel better. It's essential to drink plenty of non-caffeinated liquids, unless your doctor advises you to limit your fluid intake.
Storing and Disposing of Your Medication
Store your medication at room temperature in a dry place, away from the bathroom. Keep all medications in a safe and secure location, out of the reach of children and pets. When your medication is no longer needed or has expired, dispose of it properly. Do not flush it down the toilet or pour it down the drain unless instructed to do so by your doctor or pharmacist. If you're unsure about the best way to dispose of your medication, consult with your pharmacist. You may also want to check if there are any drug take-back programs available in your area.
What to Do If You Miss a Dose
If you miss a dose, take it as soon as you remember. However, if it's close to the time for your next scheduled dose, skip the missed dose and resume your regular dosing schedule. Do not take two doses at the same time or take extra doses to make up for the missed one.
Lifestyle & Tips
- Take with food or after meals to reduce stomach upset.
- Drink plenty of fluids to prevent kidney stones.
- Take folic acid supplements as directed by your doctor, as sulfasalazine can interfere with folate absorption.
- Avoid sun exposure or use sunscreen, as sulfasalazine can increase sun sensitivity.
- Report any unusual symptoms like fever, sore throat, rash, yellowing of skin/eyes, or unusual bleeding/bruising immediately.
Available Forms & Alternatives
Available Strengths:
Dosing & Administration
Adult Dosing
Standard Dose:
Ulcerative Colitis: Initial 1-2 g/day in 3-4 divided doses, increasing to 4-6 g/day. Maintenance 2 g/day in 2-4 divided doses. Rheumatoid Arthritis: Initial 500 mg/day for 1 week, increasing by 500 mg/week to a maintenance of 2 g/day in 2 divided doses.
Dose Range:
500 - 6000 mg
Condition-Specific Dosing:
Ulcerative Colitis (Acute):
4-6 g/day in 3-4 divided doses
Ulcerative Colitis (Maintenance):
2 g/day in 2-4 divided doses
Rheumatoid Arthritis:
1-3 g/day in 2 divided doses (target 2 g/day)
Pediatric Dosing
Neonatal:
Not established
Infant:
Not established
Child:
Ulcerative Colitis (≥6 years): Initial 40-60 mg/kg/day in 3-6 divided doses, increasing to 75 mg/kg/day (max 4 g/day). Maintenance 30 mg/kg/day in 4 divided doses. Juvenile Rheumatoid Arthritis (≥6 years): Initial 10 mg/kg/day, increasing by 10 mg/kg/week to a maintenance of 30-50 mg/kg/day in 2 divided doses (max 2 g/day).
Adolescent:
Ulcerative Colitis: Same as child dosing. Juvenile Rheumatoid Arthritis: Same as child dosing.
Dose Adjustments
Renal Impairment:
Mild:
Use with caution; monitor renal function.
Moderate:
Use with caution; consider dose reduction or increased dosing interval. Monitor renal function and sulfapyridine levels if available.
Severe:
Contraindicated in severe renal impairment.
Dialysis:
Contraindicated in severe renal impairment. Sulfapyridine is dialyzable, but 5-ASA is not significantly.
Hepatic Impairment:
Mild:
Use with caution; monitor liver function.
Moderate:
Use with caution; consider dose reduction. Monitor liver function closely.
Severe:
Contraindicated in severe hepatic impairment.
Confidence:
Medium
Pharmacology
Mechanism of Action
Sulfasalazine is a prodrug that is poorly absorbed from the gastrointestinal tract. In the colon, it is metabolized by bacterial azoreductases into two active components: sulfapyridine (SP) and 5-aminosalicylic acid (5-ASA, mesalamine). 5-ASA is believed to exert its anti-inflammatory effects locally in the colon by inhibiting prostaglandin and leukotriene synthesis, scavenging free radicals, and modulating immune cell function. Sulfapyridine is largely absorbed systemically and is thought to be responsible for the systemic effects in rheumatoid arthritis, though its precise mechanism is not fully understood. It may also contribute to some of the adverse effects.
Pharmacokinetics
Absorption:
Bioavailability:
Approximately 10-15% of intact sulfasalazine is absorbed. After cleavage, about 60-80% of sulfapyridine is absorbed, while only 10-30% of 5-ASA is absorbed.
Tmax:
Sulfasalazine: 3-10 hours; Sulfapyridine: 6-24 hours; 5-ASA: 10-24 hours (for colonic release)
FoodEffect:
Food delays absorption but does not significantly affect the extent of absorption.
Distribution:
Vd:
Sulfasalazine: 7.5 ± 1.6 L; Sulfapyridine: 0.3 L/kg; 5-ASA: 0.16 L/kg
ProteinBinding:
Sulfasalazine: >99%; Sulfapyridine: ~50%; 5-ASA: ~43%
CnssPenetration:
Limited (Sulfapyridine can cross the blood-brain barrier to some extent)
Elimination:
HalfLife:
Sulfasalazine: 5.7-10 hours; Sulfapyridine: 6-14 hours (longer in slow acetylators); 5-ASA: 0.5-1.5 hours (systemic)
Clearance:
Not readily available for intact sulfasalazine due to extensive colonic metabolism. Sulfapyridine clearance is dependent on acetylation status.
ExcretionRoute:
Sulfasalazine: Feces (major); Sulfapyridine: Urine (primarily as metabolites); 5-ASA: Urine (primarily as N-acetyl-5-ASA) and feces.
Unchanged:
Sulfasalazine: <15% in urine; Sulfapyridine: <10% in urine; 5-ASA: <1% in urine
Pharmacodynamics
OnsetOfAction:
Ulcerative Colitis: Days to weeks; Rheumatoid Arthritis: 4-12 weeks
PeakEffect:
Ulcerative Colitis: Weeks; Rheumatoid Arthritis: 12-24 weeks
DurationOfAction:
Dependent on continued dosing
Safety & Warnings
BLACK BOX WARNING
Sulfasalazine can cause serious adverse reactions, including severe hypersensitivity reactions (e.g., Stevens-Johnson syndrome, toxic epidermal necrolysis, drug rash with eosinophilia and systemic symptoms [DRESS]), blood dyscrasias (e.g., agranulocytosis, aplastic anemia, hemolytic anemia, leukopenia, thrombocytopenia), and hepatic damage. Fatalities have been reported. Patients should be instructed to report immediately any signs or symptoms of these reactions, such as fever, rash, sore throat, joint pain, malaise, pallor, purpura, or jaundice. Complete blood counts, including differential white blood cell count, and liver function tests should be performed before starting sulfasalazine and every two weeks for the first three months of therapy, and monthly for the second three months, and then once every three months thereafter, or as clinically indicated.
Side Effects
Urgent Side Effects: Seek Medical Help Right Away
Although rare, some people may experience severe and potentially life-threatening side effects while taking this medication. If you notice any of the following symptoms, contact your doctor immediately or seek emergency medical attention:
Signs of an allergic reaction: rash, hives, itching, red, swollen, blistered, or peeling skin (with or without fever), wheezing, tightness in the chest or throat, difficulty breathing, swallowing, or talking, unusual hoarseness, or swelling of the mouth, face, lips, tongue, or throat
Signs of liver problems: dark urine, fatigue, decreased appetite, stomach pain or upset, light-colored stools, vomiting, or yellow skin or eyes
Signs of kidney problems: inability to urinate, changes in urine output, blood in the urine, or sudden weight gain
Signs of infection: fever, chills, severe sore throat, ear or sinus pain, cough, increased or discolored sputum, painful urination, mouth sores, or unhealing wounds
Feeling extremely tired or weak
Pale skin
Unexplained bruising or bleeding
Swollen glands
Shortness of breath, sudden weight gain, or swelling in the arms or legs
Severe skin reactions, including Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), and other severe skin reactions, which can be life-threatening. Seek immediate medical help if you experience red, swollen, blistered, or peeling skin; skin irritation (with or without fever); red or irritated eyes; or sores in your mouth, throat, nose, or eyes.
Other Possible Side Effects
Like all medications, this drug can cause side effects. While many people may not experience any side effects or only minor ones, it's essential to discuss any concerns with your doctor. If you experience any of the following side effects or any other symptoms that bother you or persist, contact your doctor:
Headache
Stomach pain or heartburn
Upset stomach or vomiting
Decreased appetite
This list is not exhaustive, and you may experience other side effects. If you have questions or concerns, consult your doctor. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.
Although rare, some people may experience severe and potentially life-threatening side effects while taking this medication. If you notice any of the following symptoms, contact your doctor immediately or seek emergency medical attention:
Signs of an allergic reaction: rash, hives, itching, red, swollen, blistered, or peeling skin (with or without fever), wheezing, tightness in the chest or throat, difficulty breathing, swallowing, or talking, unusual hoarseness, or swelling of the mouth, face, lips, tongue, or throat
Signs of liver problems: dark urine, fatigue, decreased appetite, stomach pain or upset, light-colored stools, vomiting, or yellow skin or eyes
Signs of kidney problems: inability to urinate, changes in urine output, blood in the urine, or sudden weight gain
Signs of infection: fever, chills, severe sore throat, ear or sinus pain, cough, increased or discolored sputum, painful urination, mouth sores, or unhealing wounds
Feeling extremely tired or weak
Pale skin
Unexplained bruising or bleeding
Swollen glands
Shortness of breath, sudden weight gain, or swelling in the arms or legs
Severe skin reactions, including Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), and other severe skin reactions, which can be life-threatening. Seek immediate medical help if you experience red, swollen, blistered, or peeling skin; skin irritation (with or without fever); red or irritated eyes; or sores in your mouth, throat, nose, or eyes.
Other Possible Side Effects
Like all medications, this drug can cause side effects. While many people may not experience any side effects or only minor ones, it's essential to discuss any concerns with your doctor. If you experience any of the following side effects or any other symptoms that bother you or persist, contact your doctor:
Headache
Stomach pain or heartburn
Upset stomach or vomiting
Decreased appetite
This list is not exhaustive, and you may experience other side effects. If you have questions or concerns, consult your doctor. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.
Seek Immediate Medical Attention If You Experience:
- Severe skin rash (e.g., blistering, peeling, widespread redness)
- Fever, chills, body aches, flu-like symptoms
- Sore throat, mouth sores
- Unusual bleeding or bruising
- Yellowing of the skin or eyes (jaundice)
- Dark urine or pale stools
- Severe abdominal pain
- Swelling of the face, lips, tongue, or throat (signs of allergic reaction)
- Shortness of breath or difficulty breathing
- Severe fatigue or weakness
Before Using This Medicine
Before Taking This Medication: Important Information to Share with Your Doctor
It is essential to inform your doctor about the following:
Any allergies you have, including allergies to this medication, its components, or other substances, such as foods or drugs. Be sure to describe the allergic reaction you experienced, including any symptoms that occurred.
A known sulfa allergy, as this may affect your ability to take this medication safely.
Certain health conditions, including:
+ Bowel blockage
+ Porphyria, a disorder that affects the production of heme
+ Urinary retention or difficulty passing urine
This list is not exhaustive, and it is crucial to discuss all your medications, health problems, and concerns with your doctor. This includes:
All prescription and over-the-counter (OTC) medications you are currently taking
Any natural products or vitamins you are using
Existing health problems or conditions
To ensure your safety, do not start, stop, or change the dose of any medication without first consulting your doctor. It is vital to verify that this medication is safe to take with all your other medications and health conditions.
It is essential to inform your doctor about the following:
Any allergies you have, including allergies to this medication, its components, or other substances, such as foods or drugs. Be sure to describe the allergic reaction you experienced, including any symptoms that occurred.
A known sulfa allergy, as this may affect your ability to take this medication safely.
Certain health conditions, including:
+ Bowel blockage
+ Porphyria, a disorder that affects the production of heme
+ Urinary retention or difficulty passing urine
This list is not exhaustive, and it is crucial to discuss all your medications, health problems, and concerns with your doctor. This includes:
All prescription and over-the-counter (OTC) medications you are currently taking
Any natural products or vitamins you are using
Existing health problems or conditions
To ensure your safety, do not start, stop, or change the dose of any medication without first consulting your doctor. It is vital to verify that this medication is safe to take with all your other medications and health conditions.
Precautions & Cautions
It is essential to inform all your healthcare providers, including doctors, nurses, pharmacists, and dentists, that you are taking this medication. If you have asthma, consult with your doctor, as you may be more susceptible to the effects of this drug.
Individuals with low levels of the enzyme glucose-6-phosphate dehydrogenase (G6PD) should exercise caution, as they may be at a higher risk of developing anemia. This enzyme deficiency is more common in people of African, South Asian, Middle Eastern, and Mediterranean descent.
Regular blood tests and urine checks should be performed as directed by your doctor. Additionally, inform all your healthcare providers and laboratory personnel that you are taking this medication, as it may interfere with certain lab tests.
This medication may cause your urine or skin to turn yellow or orange, but this discoloration is harmless. However, it is crucial to be aware of the potential for severe and potentially life-threatening side effects, including allergic reactions, infections, heart problems, kidney problems, liver problems, lung problems, and blood disorders. Some patients have also experienced persistent nerve or muscle problems. Discuss any concerns with your doctor.
Men taking this medication may experience sperm problems, which could affect their ability to father a child. Although these issues may resolve after stopping the medication, it is essential to discuss any questions or concerns with your doctor.
If you notice what appears to be a tablet in your stool, consult with your doctor. It is also vital to inform your doctor if you are pregnant, plan to become pregnant, or are breastfeeding, as you will need to discuss the potential benefits and risks to you and your baby.
Individuals with low levels of the enzyme glucose-6-phosphate dehydrogenase (G6PD) should exercise caution, as they may be at a higher risk of developing anemia. This enzyme deficiency is more common in people of African, South Asian, Middle Eastern, and Mediterranean descent.
Regular blood tests and urine checks should be performed as directed by your doctor. Additionally, inform all your healthcare providers and laboratory personnel that you are taking this medication, as it may interfere with certain lab tests.
This medication may cause your urine or skin to turn yellow or orange, but this discoloration is harmless. However, it is crucial to be aware of the potential for severe and potentially life-threatening side effects, including allergic reactions, infections, heart problems, kidney problems, liver problems, lung problems, and blood disorders. Some patients have also experienced persistent nerve or muscle problems. Discuss any concerns with your doctor.
Men taking this medication may experience sperm problems, which could affect their ability to father a child. Although these issues may resolve after stopping the medication, it is essential to discuss any questions or concerns with your doctor.
If you notice what appears to be a tablet in your stool, consult with your doctor. It is also vital to inform your doctor if you are pregnant, plan to become pregnant, or are breastfeeding, as you will need to discuss the potential benefits and risks to you and your baby.
Overdose Information
Overdose Symptoms:
- Nausea
- Vomiting
- Abdominal pain
- Drowsiness
- Convulsions
- Oliguria (decreased urine output)
- Anuria (no urine output)
- Crystalluria (crystals in urine)
What to Do:
Seek immediate medical attention. Call 911 or Poison Control at 1-800-222-1222. Treatment is supportive and may include gastric lavage, emesis, forced diuresis (if renal function is adequate), and alkalinization of urine to increase sulfapyridine excretion. Monitor renal function and fluid balance.
Drug Interactions
Major Interactions
- Digoxin (decreased absorption)
- Folic acid (decreased absorption, increased deficiency risk)
- Warfarin (increased anticoagulant effect)
- Methotrexate (increased myelosuppression, especially with slow acetylators)
Moderate Interactions
- Azathioprine/Mercaptopurine (increased myelosuppression)
- Oral contraceptives (decreased efficacy)
- Antibiotics (may alter gut flora, affecting sulfasalazine metabolism)
- Phenytoin (increased phenytoin levels)
Monitoring
Baseline Monitoring
Complete Blood Count (CBC) with differential
Rationale: To establish baseline hematologic parameters and detect potential blood dyscrasias (e.g., agranulocytosis, aplastic anemia, hemolytic anemia).
Timing: Prior to initiation of therapy
Liver Function Tests (LFTs) including AST, ALT, alkaline phosphatase, bilirubin
Rationale: To establish baseline hepatic function and detect potential hepatotoxicity.
Timing: Prior to initiation of therapy
Renal Function Tests (serum creatinine, BUN, urinalysis)
Rationale: To establish baseline renal function and detect potential renal impairment or crystalluria.
Timing: Prior to initiation of therapy
Glucose-6-Phosphate Dehydrogenase (G6PD) deficiency screen
Rationale: To identify patients at risk for hemolytic anemia, especially in individuals of African, Mediterranean, or Asian descent.
Timing: Consider prior to initiation, especially in at-risk populations
Routine Monitoring
Complete Blood Count (CBC) with differential
Frequency: Every 2 weeks for the first 3 months, then monthly for the next 3 months, then every 3 months thereafter, and as clinically indicated.
Target: Within normal limits; monitor for significant drops in WBC, neutrophil count, or hemoglobin.
Action Threshold: Discontinue if WBC <3,500/mm³ or neutrophil count <1,500/mm³.
Liver Function Tests (LFTs)
Frequency: Every 2 weeks for the first 3 months, then monthly for the next 3 months, then every 3 months thereafter, and as clinically indicated.
Target: Within normal limits; monitor for significant elevations.
Action Threshold: Discontinue if LFTs are significantly elevated (e.g., >3x ULN).
Renal Function Tests (serum creatinine, BUN, urinalysis)
Frequency: Every 2 weeks for the first 3 months, then monthly for the next 3 months, then every 3 months thereafter, and as clinically indicated.
Target: Within normal limits; monitor for significant changes.
Action Threshold: Discontinue if renal function significantly deteriorates.
Folic Acid levels
Frequency: Periodically, especially if signs of deficiency are present or if patient is at high risk.
Target: Within normal limits.
Action Threshold: Supplement with folic acid if levels are low.
Symptom Monitoring
- Sore throat
- Fever
- Malaise
- Rash (especially severe or widespread)
- Jaundice
- Unusual bleeding or bruising
- Dark urine
- Pale stools
- Abdominal pain
- Nausea/vomiting
- Headache
- Shortness of breath
Special Patient Groups
Pregnancy
Generally considered safe for use during pregnancy (Category B). However, sulfasalazine can interfere with folate absorption, which is critical for fetal development. Folic acid supplementation (e.g., 2 mg/day) is strongly recommended for pregnant women taking sulfasalazine.
Trimester-Specific Risks:
First Trimester:
Low risk of teratogenicity, but folate supplementation is crucial to prevent neural tube defects.
Second Trimester:
Generally considered safe with continued folate supplementation.
Third Trimester:
Generally considered safe with continued folate supplementation. Theoretical risk of kernicterus in neonates if used near term, but clinical evidence is limited and risk is generally low with healthy full-term infants.
Lactation
Sulfasalazine and its metabolites (sulfapyridine and 5-ASA) are excreted into breast milk. While generally considered compatible with breastfeeding, caution is advised. Monitor breastfed infants for signs of diarrhea, bloody stools, or rash. Avoid use in premature infants or those with G6PD deficiency or hyperbilirubinemia.
Infant Risk:
L3 (Moderately Safe) - Monitor infant for adverse effects. Risk of diarrhea or rash in some infants. Theoretical risk of kernicterus in jaundiced or premature infants due to sulfapyridine.
Pediatric Use
Approved for use in children 6 years and older for ulcerative colitis and juvenile rheumatoid arthritis. Close monitoring for adverse effects, especially blood dyscrasias and hypersensitivity reactions, is essential. Dose is weight-based.
Geriatric Use
Use with caution in elderly patients due to increased risk of adverse reactions, particularly blood dyscrasias and renal/hepatic impairment. Start with lower doses and titrate slowly. Monitor renal and hepatic function closely.
Clinical Information
Clinical Pearls
- Sulfasalazine is a prodrug; its efficacy relies on bacterial metabolism in the colon. EC/DR formulation helps deliver the drug to the colon, reducing upper GI side effects.
- Folic acid supplementation is crucial for all patients on sulfasalazine, especially women of childbearing potential and pregnant women, due to its antifolate effect.
- Patients should be advised to drink plenty of water to prevent crystalluria and kidney stone formation.
- The most common side effects are GI upset (nausea, vomiting, anorexia) and headache, which often improve with dose titration or taking with food.
- Serious adverse effects like blood dyscrasias, hepatotoxicity, and severe skin reactions (SJS/TEN, DRESS) can occur and require immediate discontinuation and medical attention. Regular monitoring of CBC and LFTs is mandatory.
- Oligospermia (reversible) is a known side effect in males, which can affect fertility. Patients should be counseled on this if planning conception.
- Slow acetylators may have higher sulfapyridine levels and thus a higher risk of dose-related adverse effects.
Alternative Therapies
- Mesalamine (5-ASA formulations like Lialda, Apriso, Asacol HD, Pentasa)
- Olsalazine
- Balsalazide
- Corticosteroids (e.g., Prednisone, Budesonide)
- Immunomodulators (e.g., Azathioprine, Mercaptopurine, Methotrexate)
- Biologic agents (e.g., Infliximab, Adalimumab, Vedolizumab, Ustekinumab)
- JAK inhibitors (e.g., Tofacitinib)
Cost & Coverage
Average Cost:
Varies widely, typically $30-$150 per 30 tablets
Generic Available:
Yes
Insurance Coverage:
Tier 1 or 2 (Generic)
General Drug Facts
If your symptoms or health issues persist or worsen, it is essential to contact your doctor for further guidance. To ensure your safety, never share your medication with others or take someone else's medication. Some medications may come with an additional patient information leaflet, so it's a good idea to check with your pharmacist. If you have any questions or concerns about this medication, don't hesitate to discuss them with your doctor, nurse, pharmacist, or other healthcare provider. In the event of a suspected overdose, immediately call your local poison control center or seek emergency medical attention. When seeking help, be prepared to provide detailed information about the overdose, including the medication taken, the amount, and the time it occurred.