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Mercaptopurine (also called 6-Mercaptopurine, 6-MP or its brand name Purinethol) is an immunosuppressive drug
Immunosuppressive drug

Immunosuppressive drugs or immunosuppressive agents are medication that inhibit or prevent activity of the immune system. They are used in immunosuppression to:...
.

It is a thiopurine
Thiopurine

Sorry, no overview for this topic
.

s used to treat leukemia
Leukemia

Leukemia is a cancer of the blood or bone marrow and is characterized by an abnormal proliferation of blood Cell , usually white blood cells ....
. It is also used for pediatric non-Hodgkin's lymphoma, polycythemia vera
Polycythemia vera

Primary polycythemia, often called polycythemia vera , polycythemia rubra vera , or erythremia, occurs when excess red blood cells are produced as a result of an abnormality of the bone marrow and occasionally in the kidneys....
, psoriatic arthritis
Psoriatic arthritis

Psoriatic arthritis is a type of inflammatory arthritis that, according to the National Psoriasis Foundation, affects around 10-30% of people suffering from the chronic skin condition psoriasis....
, and inflammatory bowel disease
Inflammatory bowel disease

In medicine, inflammatory bowel disease is a group of inflammation conditions of the colon and small intestine. The major types of IBD are Crohn's disease and ulcerative colitis.....
 (such as Crohn's Disease
Crohn's disease

Crohn's disease is an inflammatory disease which may affect any part of the gastrointestinal tract from mouth to anus, causing a wide variety of symptoms....
 and ulcerative colitis
Ulcerative colitis

Ulcerative colitis is a form of inflammatory bowel disease . Ulcerative colitis is a form of colitis, a disease of the intestine, specifically the large intestine or colon , that includes characteristic Peptic ulcer, or open sores, in the colon....
).

It has demonstrated some in vitro effectiveness against Mycobacterium paratuberculosis.

aptopurine is converted to the corresponding ribonucleotide
RNA

Ribonucleic acid is a type of molecule that consists of a long chain of nucleotide units. Each nucleotide consists of a nucleobase, a ribose sugar, and a phosphate....
.






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Encyclopedia


Mercaptopurine (also called 6-Mercaptopurine, 6-MP or its brand name Purinethol) is an immunosuppressive drug
Immunosuppressive drug

Immunosuppressive drugs or immunosuppressive agents are medication that inhibit or prevent activity of the immune system. They are used in immunosuppression to:...
.

It is a thiopurine
Thiopurine

Sorry, no overview for this topic
.

Uses

It is used to treat leukemia
Leukemia

Leukemia is a cancer of the blood or bone marrow and is characterized by an abnormal proliferation of blood Cell , usually white blood cells ....
. It is also used for pediatric non-Hodgkin's lymphoma, polycythemia vera
Polycythemia vera

Primary polycythemia, often called polycythemia vera , polycythemia rubra vera , or erythremia, occurs when excess red blood cells are produced as a result of an abnormality of the bone marrow and occasionally in the kidneys....
, psoriatic arthritis
Psoriatic arthritis

Psoriatic arthritis is a type of inflammatory arthritis that, according to the National Psoriasis Foundation, affects around 10-30% of people suffering from the chronic skin condition psoriasis....
, and inflammatory bowel disease
Inflammatory bowel disease

In medicine, inflammatory bowel disease is a group of inflammation conditions of the colon and small intestine. The major types of IBD are Crohn's disease and ulcerative colitis.....
 (such as Crohn's Disease
Crohn's disease

Crohn's disease is an inflammatory disease which may affect any part of the gastrointestinal tract from mouth to anus, causing a wide variety of symptoms....
 and ulcerative colitis
Ulcerative colitis

Ulcerative colitis is a form of inflammatory bowel disease . Ulcerative colitis is a form of colitis, a disease of the intestine, specifically the large intestine or colon , that includes characteristic Peptic ulcer, or open sores, in the colon....
).

It has demonstrated some in vitro effectiveness against Mycobacterium paratuberculosis.

Mechanisms of Action

Mercaptopurine is converted to the corresponding ribonucleotide
RNA

Ribonucleic acid is a type of molecule that consists of a long chain of nucleotide units. Each nucleotide consists of a nucleobase, a ribose sugar, and a phosphate....
. 6-MP ribonucleotide inhibits purine nucleotide synthesis and metabolism. This alters the synthesis and function of RNA
RNA

Ribonucleic acid is a type of molecule that consists of a long chain of nucleotide units. Each nucleotide consists of a nucleobase, a ribose sugar, and a phosphate....
 and DNA
DNA

Deoxyribonucleic acid is a nucleic acid that contains the genetics instructions used in the development and functioning of all known living organisms and some viruses....
. Mercaptopurine interferes with nucleotide
Nucleotide

Nucleotides are molecules that comprise the structural units of RNA and DNA. Additionally, nucleotides play central roles in metabolism. In that capacity, they serve as sources of chemical energy , participate in cell signaling , and are incorporated into important cofactors of enzymatic reactions ....
 interconversion and glycoprotein synthesis.

Adverse reactions


Some of the adverse reaction
Adverse drug reaction

An adverse drug reaction or adverse drug event is an expression that describes the unwanted, negative consequences associated with the use of given medications....
s of taking mercaptopurine might include diarrhea, nausea, vomiting, loss of appetite, stomach/abdominal pain, weakness, skin rash
Rash

A rash is a change of the skin which affects its color, appearance, or texture. A rash may be localized in one part of the body, or affect all the skin....
, darkening of the skin, or hair loss. Serious adverse reactions include mouth sores, fever
Fever

Fever is a frequent medical sign that describes an increase in internal body temperature to levels above normal. Fever is most accurately characterized as a temporary elevation in the body's thermoregulatory set-point, usually by about 1?2 ?C ....
, sore throat
Sore Throat

Sore Throat were a United Kingdom crust punk / grindcore band, formed in Yorkshire in 1987. They are known for being one of the earliest exponents of the grindcore subgenre known as "noisecore", as well launching the careers of several prominent members of the British heavy metal music community....
, easy bruising or bleeding, pinpoint red spots on the skin, yellowing of eyes or skin, dark urine
Urine

Urine is a liquid waste product of the body secreted by the kidneys by a process of filtration from blood called urination and excreted through the urethra....
, painful or difficult urination. Unlikely but serious side effects include: black or tarry stools (melena
Melena

In medicine, melena or melaena refers to the black, "tarry" feces that are associated with gastrointestinal hemorrhage. The black color is caused by oxidation of the iron in hemoglobin during its passage through the ileum and colon ....
), bloody stools, and bloody urine
Urine

Urine is a liquid waste product of the body secreted by the kidneys by a process of filtration from blood called urination and excreted through the urethra....
.

Symptoms of allergic reaction to mercaptopurine include rash
Rash

A rash is a change of the skin which affects its color, appearance, or texture. A rash may be localized in one part of the body, or affect all the skin....
, itching, swelling
Swelling

Swelling can mean:* In medicine:** Swelling is the enlargement of organs caused by accumulation of excess fluid in tissues, called edema.* In engineering:...
, dizziness
Dizziness

Dizziness describes a number of subjective symptoms, which the patient may describe as feelings of lightheadedness, floating, wooziness, giddiness, confusion, disorientation or loss of balance....
, trouble breathing
Breathing

Breathing takes oxygen in and carbon dioxide out of the body. Aerobic respiration organisms require oxygen to create energy via Cellular respiration, in the form of the metabolism of energy-rich molecules such as glucose....
.

Mercaptopurine causes myelosuppression, suppressing the production of white blood cell
White blood cell

White blood cells , or leukocytes , are cell of the immune system defending the body against both infectious disease and foreign materials....
s and red blood cell
Red blood cell

Red blood cells are the most common type of blood cell and the vertebrate body's principal means of delivering oxygen to the body tissues via the blood....
s. It may be toxic to bone marrow
Bone marrow

Bone marrow is the flexible biological tissue found in the hollow interior of bones. In adults, marrow in large bones produces new blood cells....
. Weekly blood counts are recommended for patients on mercaptopurine. The patient should stop taking the medication at least temporarily if there is an unexplained, abnormally large drop in white blood cell count, or any other blood count.

Patients who exhibit myelosuppression or bone marrow
Bone marrow

Bone marrow is the flexible biological tissue found in the hollow interior of bones. In adults, marrow in large bones produces new blood cells....
 toxicity should be tested for Thiopurine methyltransferase
Thiopurine methyltransferase

Thiopurine methyltransferase or thiopurine S-methyltransferase is an enzyme that methylation thiopurine compounds. The methyl donor is S-adenosyl-L-methionine, which is converted to S-adenosyl-L-homocysteine....
 (TPMT) enzyme deficiency. Patients with TPMT deficiency are much more likely to develop dangerous myelosuppression. In such patients it may be possible to continue using mercaptopurine, but at a lower dose.

Drug Interactions

Allopurinol inhibits xanthine oxidase
Xanthine oxidase

The enzyme xanthine oxidase, or XO, catalyzes the oxidation of hypoxanthine to xanthine and can further catalyze the oxidation of xanthine to uric acid....
, the enzyme that breaks down mercaptopurine. Those who take allopurinol
Allopurinol

Allopurinol is a drug used primarily to treat hyperuricemia and its complications, including chronic gout....
 (often used to prevent gout) are at risk for mercaptopurine toxicity. The dose should be reduced or allopurinol should be discontinued.

Precautions


Mercaptopurine can lower the body's ability to fight off infection. Those taking mercaptopurine should get permission from a doctor in order to receive immunization
Immunization

Immunization, or immunisation, is the process by which an individual's immune system becomes fortified against an agent .When an immune system is exposed to molecules that are foreign to the body , it will orchestrate an immune response, but it can also develop the ability to quickly respond to a subsequent encounter ....
s and vaccination
Vaccination

Vaccination is the administration of antigenic material to produce immunity to a disease. Vaccines can prevent or ameliorate the effects of infection by a pathogen....
s. It is also recommended that while on the drug one should avoid those who have recently received oral polio vaccine.

This drug is traditionally not recommended during pregnancy but this issue has been debated and current evidence indicates that pregnant women on the drug show no increase in fetal abnormalities. However, women receiving mercaptopurine during the first trimester of pregnancy have an increased incidence of abortion. Davis et al 1999 found that mercaptopurine, compared to methotrexate
Methotrexate

Methotrexate , abbreviated MTX and formerly known as amethopterin, is an antimetabolite and antifolate drug used in treatment of cancer and autoimmune diseases....
, was ineffective as a single-agent abortifacient; every woman in the mercaptopurine arm of the study had fetal cardiac activity at follow-up (two weeks later) and was given a suction abortion.

Mercaptopurine causes changes to chromosome
Chromosome

A chromosome is an organized structure of DNA and protein that is found in Cell . A chromosome is a single piece of DNA that contains many genes, regulatory sequence and other genetic sequence....
s in animals and humans. In mice these changes have given rise to lethal mutation
Mutation

In biology, mutations are changes to the nucleotide sequence of the genetic material of an organism. Mutations can be caused by copying errors in the genetic material during cell division, by exposure to ultraviolet or ionizing radiation, chemical mutagens, or virus , or can be induced by the organism, itself, by cellular processes such as s...
s. Therefore the drug has the potential to be cancer causing in humans.

See also

  • azathioprine
    Azathioprine

    Azathioprine is an immunosuppressant used in organ transplantation, autoimmune disease such as rheumatoid arthritis and pemphigus or inflammatory bowel disease such as Crohn's disease and ulcerative colitis as well as multiple sclerosis....


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