Sulfasalazine, sold under the brand name Azulfidine among others, is a

medication A medication (also called medicament, medicine, pharmaceutical drug, medicinal drug or simply drug) is a drug used to diagnose, cure, treat, or prevent disease. Drug therapy ( pharmacotherapy) is an important part of the medical field an ...

used to treat

rheumatoid arthritis Rheumatoid arthritis (RA) is a long-term autoimmune disorder that primarily affects synovial joint, joints. It typically results in warm, swollen, and painful joints. Pain and stiffness often worsen following rest. Most commonly, the wrist and ...

ulcerative colitis Ulcerative colitis (UC) is a long-term condition that results in inflammation and ulcers of the colon and rectum. The primary symptoms of active disease are abdominal pain and diarrhea mixed with blood ( hematochezia). Weight loss, fever, an ...

, and

Crohn's disease Crohn's disease is a type of inflammatory bowel disease (IBD) that may affect any segment of the gastrointestinal tract. Symptoms often include abdominal pain, diarrhea (which may be bloody if inflammation is severe), fever, abdominal distension, ...

. It is considered by some to be a first-line treatment in rheumatoid arthritis. It is taken

by mouth Oral administration is a route of administration where a substance is taken through the mouth. Per os abbreviated to P.O. is sometimes used as a direction for medication to be taken orally. Many medications are taken orally because they are i ...

. Significant side effects occur in about 25% of people. Commonly these include loss of appetite, nausea, headache, and rash. Severe side effects include

bone marrow suppression Bone marrow suppression also known as myelotoxicity or myelosuppression, is the decrease in production of cells responsible for providing immunity (leukocytes), carrying oxygen ( erythrocytes), and/or those responsible for normal blood clotting ( ...

liver problems Liver disease, or hepatic disease, is any of many diseases of the liver. If long-lasting it is termed chronic liver disease. Although the diseases differ in detail, liver diseases often have features in common. Signs and symptoms Some of the sig ...

Stevens–Johnson syndrome Stevens–Johnson syndrome (SJS) is a type of severe skin reaction. Together with toxic epidermal necrolysis (TEN) and Stevens–Johnson/toxic epidermal necrolysis (SJS/TEN), it forms a spectrum of disease, with SJS being less severe. Eryth ...

, and

kidney problems Kidney failure, also known as end-stage kidney disease, is a medical condition in which the kidneys can no longer adequately filter waste products from the blood, functioning at less than 15% of normal levels. Kidney failure is classified as eit ...

. It should not be used in people allergic to

aspirin Aspirin, also known as acetylsalicylic acid (ASA), is a nonsteroidal anti-inflammatory drug (NSAID) used to reduce pain, fever, and/or inflammation, and as an antithrombotic. Specific inflammatory conditions which aspirin is used to treat in ...

sulfonamide In organic chemistry, the sulfonamide functional group (also spelled sulphonamide) is an organosulfur group with the structure . It consists of a sulfonyl group () connected to an amine group (). Relatively speaking this group is unreactiv ...

. Use during

pregnancy Pregnancy is the time during which one or more offspring develops ( gestates) inside a woman's uterus (womb). A multiple pregnancy involves more than one offspring, such as with twins. Pregnancy usually occurs by sexual intercourse, but ...

appears to be safe for the baby. Sulfasalazine is in the

disease-modifying antirheumatic drugs Disease-modifying antirheumatic drugs (DMARDs) comprise a category of otherwise unrelated disease-modifying drugs defined by their use in rheumatoid arthritis to slow down disease progression. The term is often used in contrast to nonsteroidal ...

(DMARDs) family of medications. It is unclear exactly how it works. One proposed mechanism is the inhibition of

prostaglandin The prostaglandins (PG) are a group of physiologically active lipid compounds called eicosanoids having diverse hormone-like effects in animals. Prostaglandins have been found in almost every tissue in humans and other animals. They are der ...

s, resulting in local

anti-inflammatory Anti-inflammatory is the property of a substance or treatment that reduces inflammation or swelling. Anti-inflammatory drugs, also called anti-inflammatories, make up about half of analgesics. These drugs remedy pain by reducing inflammation as ...

effects in the colon. The medication is broken down by

intestinal bacteria Gut microbiota, gut microbiome, or gut flora, are the microorganisms, including bacteria, archaea, fungi, and viruses that live in the digestive tracts of animals. The gastrointestinal metagenome is the aggregate of all the genomes of the g ...

into

sulfapyridine Sulfapyridine (INN; also known as sulphapyridine) is a sulfanilamide antibacterial medication. At one time, it was commonly referred to as M&B 693. Sulfapyridine is no longer prescribed for treatment of infections in humans. However, it may be ...

and

5-aminosalicylic acid Mesalazine, also known as mesalamine or 5-aminosalicylic acid (5-ASA), is a medication used to treat inflammatory bowel disease, including ulcerative colitis and Crohn's disease. It is generally used for mildly to moderately severe disease. It ...

. That which is absorbed is excreted by the kidneys and in the bile. Sulfasalazine was approved for medical use in the United States in 1950. It is on the

World Health Organization's List of Essential Medicines The WHO Model List of Essential Medicines (aka Essential Medicines List or EML), published by the World Health Organization (WHO), contains the medications considered to be most effective and safe to meet the most important needs in a health s ...

. Sulfasalazine is available as a

generic medication A generic drug is a pharmaceutical drug that contains the same chemical substance as a drug that was originally protected by chemical patents. Generic drugs are allowed for sale after the patents on the original drugs expire. Because the active c ...

. In 2020, it was the 284th most commonly prescribed medication in the United States, with more than 1million prescriptions.

Medical uses

Sulfasalazine is used in the treatment of

inflammatory bowel disease Inflammatory bowel disease (IBD) is a group of inflammatory conditions of the colon and small intestine, Crohn's disease and ulcerative colitis being the principal types. Crohn's disease affects the small intestine and large intestine, as wel ...

, including

and

. It is also indicated for use in

and used in other types of inflammatory arthritis (e.g.

psoriatic arthritis Psoriatic arthritis is a long-term inflammatory arthritis that occurs in people affected by the autoimmune disease psoriasis. The classic feature of psoriatic arthritis is swelling of entire fingers and toes with a sausage-like appearance. ...

and

reactive arthritis Reactive arthritis, also known as Reiter's syndrome, is a form of inflammatory arthritis that develops in response to an infection in another part of the body (cross-reactivity). Coming into contact with bacteria and developing an infection can ...

). It is usually not given to children under two years of age.

Side effects

Use of sulfasalazine is contraindicated in people with sulfa allergies and in those with

urinary tract obstruction Urinary tract obstruction is a urologic disease consisting of a decrease in the free passage of urine through one or both ureters and/or the urethra. It is a cause of urinary retention. Complete obstruction of the urinary tract requires prompt trea ...

s, intestinal obstructions, and severe

liver The liver is a major organ only found in vertebrates which performs many essential biological functions such as detoxification of the organism, and the synthesis of proteins and biochemicals necessary for digestion and growth. In humans, it ...

. Sulfasalazine metabolizes to sulfapyridine. Serum levels should be monitored every three months, and more frequently at the outset. Serum levels above 50 μg/L are associated with side effects. In rare cases, sulfasalazine can cause severe depression in young males. It can also cause oligospermia and temporary

infertility Infertility is the inability of a person, animal or plant to reproduce by natural means. It is usually not the natural state of a healthy adult, except notably among certain eusocial species (mostly haplodiploid insects). It is the normal st ...

. Immune

thrombocytopenia Thrombocytopenia is a condition characterized by abnormally low levels of platelets, also known as thrombocytes, in the blood. It is the most common coagulation disorder among intensive care patients and is seen in a fifth of medical patients a ...

has been reported. Sulfasalazine inhibits

dihydropteroate synthase Dihydropteroate synthase is an enzyme classified under . It produces dihydropteroate in bacteria, but it is not expressed in most eukaryotes including humans. This makes it a useful target for sulfonamide In organic chemistry, the sulfona ...

, and can cause

folate deficiency Folate deficiency, also known as vitamin B9 deficiency, is a low level of folate and derivatives in the body. Signs of folate deficiency are often subtle. A low number of red blood cells (anemia) is a late finding in folate deficiency and folat ...

and

megaloblastic anemia Megaloblastic anemia is a type of macrocytic anemia. An anemia is a red blood cell defect that can lead to an undersupply of oxygen. Megaloblastic anemia results from inhibition of DNA synthesis during red blood cell production. When DNA synthe ...

. and various other undesirable effects. Sulfasalazine can cause

hemolytic anemia Hemolytic anemia or haemolytic anaemia is a form of anemia due to hemolysis, the abnormal breakdown of red blood cells (RBCs), either in the blood vessels (intravascular hemolysis) or elsewhere in the human body (extravascular). This most commonly ...

in people with

G6PD deficiency Glucose-6-phosphate dehydrogenase deficiency (G6PDD), which is the most common enzyme deficiency worldwide, is an inborn error of metabolism that predisposes to red blood cell breakdown. Most of the time, those who are affected have no symptoms. ...

. Sulfasalazine can cause kidney stones. Sulfasalazine may cause stomach upset,

nausea Nausea is a diffuse sensation of unease and discomfort, sometimes perceived as an urge to vomit. While not painful, it can be a debilitating symptom if prolonged and has been described as placing discomfort on the chest, abdomen, or back of the ...

, vomiting, loss of

appetite Appetite is the desire to eat food items, usually due to hunger. Appealing foods can stimulate appetite even when hunger is absent, although appetite can be greatly reduced by satiety. Appetite exists in all higher life-forms, and serves to reg ...

, headache,

dizziness Dizziness is an imprecise term that can refer to a sense of disorientation in space, vertigo, or lightheadedness. It can also refer to disequilibrium or a non-specific feeling, such as giddiness or foolishness. Dizziness is a common medical ...

, or unusual tiredness. Skin and urine can become orange, with occasional allergic reactions. Sulfasalazine may cause

sulfhemoglobinemia Sulfhemoglobinemia is a rare condition in which there is excess sulfhemoglobin (SulfHb) in the blood. The pigment is a greenish derivative of hemoglobin which cannot be converted back to normal, functional hemoglobin. It causes cyanosis even at ...

Pharmacology

Around 90% of a dose of sulfasalazine reaches the colon, where most of it is metabolized by bacteria into

and

mesalazine Mesalazine, also known as mesalamine or 5-aminosalicylic acid (5-ASA), is a medication used to treat inflammatory bowel disease, including ulcerative colitis and Crohn's disease. It is generally used for mildly to moderately severe disease. It ...

(also known as 5-aminosalicylic acid or 5-ASA). Both metabolites are active; most of the sulfapyridine is absorbed and then further metabolized, but most mesalazine is not, and remains in the colon. A mix of unchanged, hydroxylated, and glucuronidated sulfapyridine is eliminated in urine, as is acetylated mesalazine and unmetabolized sulfasalazine. The mechanism of action is not clear, but it appears that sulfasalazine and its metabolites have

immunosuppressive Immunosuppression is a reduction of the activation or efficacy of the immune system. Some portions of the immune system itself have immunosuppressive effects on other parts of the immune system, and immunosuppression may occur as an adverse react ...

, antibacterial, and anti-inflammatory effects. It also appears to inhibit the

cystine Cystine is the oxidized derivative of the amino acid cysteine and has the formula (SCH2CH(NH2)CO2H)2. It is a white solid that is poorly soluble in water. As a residue in proteins, cystine serves two functions: a site of redox reactions and a m ...

glutamate Glutamic acid (symbol Glu or E; the ionic form is known as glutamate) is an α-amino acid that is used by almost all living beings in the biosynthesis of proteins. It is a non-essential nutrient for humans, meaning that the human body can syn ...

antiporter An antiporter (also called exchanger or counter-transporter) is a cotransporter and integral membrane protein involved in secondary active transport of two or more different molecules or ions across a phospholipid membrane such as the plasma m ...

Chemistry

It is a

codrug A codrug or "mutual prodrug" consists of two synergistic drugs chemically linked together to a ''single molecule'', in order to improve the drug delivery properties of one or both drugs. An effective codrug should be pharmacologically inactive ...

which is a combination of

and

coupled with an azo linkage.

Cost

In people with rheumatoid arthritis, the

cost-effectiveness Cost-effectiveness analysis (CEA) is a form of economic analysis that compares the relative costs and outcomes (effects) of different courses of action. Cost-effectiveness analysis is distinct from cost–benefit analysis, which assigns a monetar ...

of sulfasalazine is improved by combining it with other drugs. It is commonly used in treating

in part due to its cost effectiveness.

Research

Sulfasalazine has been studied in

cirrhosis Cirrhosis, also known as liver cirrhosis or hepatic cirrhosis, and end-stage liver disease, is the impaired liver function caused by the formation of scar tissue known as fibrosis due to damage caused by liver disease. Damage causes tissue repai ...

psoriasis Psoriasis is a long-lasting, noncontagious autoimmune disease characterized by raised areas of abnormal skin. These areas are red, pink, or purple, dry, itchy, and scaly. Psoriasis varies in severity from small, localized patches to complet ...

, idiopathic

urticaria Hives, also known as urticaria, is a kind of skin rash with red, raised, itchy bumps. Hives may burn or sting. The patches of rash may appear on different body parts, with variable duration from minutes to days, and does not leave any long-lasti ...

, and

amyloidosis Amyloidosis is a group of diseases in which abnormal proteins, known as amyloid fibrils, build up in tissue. There are several non-specific and vague signs and symptoms associated with amyloidosis. These include fatigue, peripheral edema, weig ...

References

External links

* {{Portal bar, Medicine Azo compounds Codrugs Drugs acting on the gastrointestinal system and metabolism IARC Group 2B carcinogens 2-Pyridyl compounds Salicylic acids Sulfonamides World Health Organization essential medicines Wikipedia medicine articles ready to translate Disease-modifying antirheumatic drugs