Mercaptopurine 50 mg Tablet, 25-count
🆔 Identity & classification
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🏷️ RxNorm drug class
This medicine belongs to the Nucleoside Metabolic Inhibitor class.
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🏭 Manufacturer & labeler
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🩺 Clinical
Mercaptopurine is used alone or with other chemotherapy drugs to treat acute lymphocytic leukemia (ALL; also called acute lymphoblastic leukemia and acute lymphatic leukemia; a type of cancer that begins in the white blood cells). Mercaptopurine is in a class of medications called purine antagonists. It works by stopping the growth of cancer cells.
Read the full MedlinePlus article ↗- Mercaptopurine is a chemotherapy medicine used to help keep acute lymphoblastic leukemia (ALL) — a type of blood cancer — in remission. It's used during the maintenance phase of tr...
- What exactly is mercaptopurine used for?
- Either is fine, but you need to be consistent. Food reduces how much of the medicine your body absorbs, so if you always take it with a meal or always take it without food, your do...
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Patient education
Supplement & herbal interactions
Some supplements/herbs that may interact with Mercaptopurine — tap one for details:
Mercaptopurine may be associated with lower levels of 1 nutrient — worth a chat with your pharmacist, not a cause for alarm.
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Ask a licensed pharmacist directly — free, answered by our team.
💊 What it looks like
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🧪 Inactive Ingredients / Excipients
Inactive ingredients, also called excipients, are components of the drug product other than the active ingredient. They may include fillers, dyes, coatings, preservatives, flavors, or other formulation ingredients.
💡 Tap an ingredient (hover on desktop) to see what it is and why it’s used.
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UNII EWQ57Q8I5X
Lactose monohydrate is a natural sugar derived from milk. It serves as a filler and binder in tablets and capsules, helping create the proper size, texture, and consistency of the medicine.
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UNII 70097M6I30
Magnesium stearate is a salt made from magnesium and stearic acid, a fatty substance. It's used in tablets and capsules as a lubricant and glidant to help ingredients flow smoothly during manufacturing and prevent sticking.
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UNII O8232NY3SJ
A plant-based carbohydrate derived from corn kernels. It acts as a filler to add bulk, a binder to hold ingredients together, and a disintegrant to help the tablet break apart in your stomach for absorption.
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UNII 8I089SAH3T
A carbohydrate powder extracted from potatoes. It serves as a filler to add bulk and volume to the tablet or capsule, and as a disintegrant to help the medicine break apart and release its active ingredient in your body.
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UNII 4ELV7Z65AP
Stearic acid is a fatty acid derived from plant or animal sources. It acts as a binder and lubricant in tablets and capsules, helping them hold together and flow smoothly during manufacturing.
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UNII 059QF0KO0R
Water is a liquid solvent that dissolves and mixes ingredients together in liquid medicines, syrups, and injections. It helps distribute the active drug evenly throughout the product.
6 inactive ingredients listed in the exact product block matched to this NDC.
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ingredient classCode="IACT" elements from the exact product block matched by this NDC. Label-section narrative from DailyMed / the openFDA label index is shown separately when available.Inactive ingredient FAQ
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💲 Pricing
A drug doesn't have one price. Each row is a different public payment system, and none is what you'd pay at the counter — that depends on your insurance. The ⓘ on each row explains what it measures.
| Price system | Per ea | Per package |
|---|---|---|
| Retail pharmacies payNADAC · weekly | $1.011 | $25.27 / 25 tablets |
| Medicaid paysCMS SDUD · 12 mo | No recent Medicaid claims on file for this NDC — rare and low-volume NDCs are suppressed in the public data. | |
| Medicare drug plans payPart D · Q2 2026 | $1.77 | $44.14 / 25 tablets |
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🔁 Therapeutic equivalents
| Product | Labeler | Pack | NADAC/unit | TE | Status | Price vs. this |
|---|---|---|---|---|---|---|
| Mercaptopurine 50 mg 00054-4581-11 | Hikma | 25 tablets | $1.011 | AB | Availability likely | — |
| Mercaptopurine 50 mgthis 71921-0150-02 | Florida | 25 tablets | $1.011 | AB | Availability likely | — |
| Mercaptopurine 50 mg 51407-0983-25 | Golden | 250 tablets | — | AB | FDA listed | — |
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⏳ Availability & generic status
FDA-approved generic versions are listed, and recent pricing/market data suggests they may be available — see Therapeutic equivalents.
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📊 Medicare Part D spend CMS · PART D · 2026 (Q1)
🔬 Reported adverse events (FAERS)
Top reported reactions
Age at onset
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Serious outcomes
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📦 Packaging — all sizes for this product
| Package NDC | Description | Per unit | Per pack | Marketing start | Status |
|---|---|---|---|---|---|
| 71921-0150-02 You're viewing this | 25 TABLET in 1 BOTTLE (71921-150-02) | $1.01 / ea | $25.27 | 2026-01-30 | Active |
| 71921-0150-25 | 250 TABLET in 1 BOTTLE (71921-150-25) | $1.01 / ea | $252.73 | 2026-01-30 | Active |
You're viewing the smallest of 2 pack sizes for this product.
This pack has the lowest per-ea cost of the 2 priced pack sizes ($1.01 NADAC).
Pack size FAQ
What quantity is in NDC 71921-0150-02?
What is the difference between NDC 71921-0150-02 and NDC 71921-0150-25?
What NDC number is used to bill for this package of Mercaptopurine 50 mg Tablet?
Prices are the latest CMS NADAC pharmacy acquisition cost per NDC; per-pack figures are per-unit × pack quantity, shown only when the pack is denominated in the same measure NADAC prices.
📄 Full prescribing information FDA SPL
🎯 Indications and Usage ▾
1 INDICATIONS & USAGE Mercaptopurine tablets is a nucleoside metabolic inhibitor indicated for treatment of adult and pediatric patients with acute lymphoblastic leukemia (ALL) as part of a combination chemotherapy maintenance regimen. (1.1)
1.1Acute Lymphoblastic Leukemia Mercaptopurine tablets are indicated for treatment of adult and pediatric patients with acute lymphoblastic leukemia (ALL) as part of a combination chemotherapy maintenance regimen.
⏱️ Dosage and Administration ▾
2 DOSAGE & ADMINISTRATION The recommended starting dose of mercaptopurine tablets is 1.5 mg/kg to 2.5 mg/kg orally once daily as part of a combination chemotherapy maintenance regimen. Adjust dose to maintain desirable absolute neutrophil count and for excessive myelosuppression. (2.1) Renal Impairment : Use the lowest recommended starting dose or increase the dosing interval.
(2.3, 8.6) Hepatic Impairment : Use the lowest recommended starting dose. (2.3, 8.7)
2.1Recommended Dosage The recommended starting dosage of mercaptopurine tablets is 1.5 mg/kg to 2.5 mg/kg orally once daily as part of combination chemotherapy maintenance regimen. A recommended dosage for patients less than 17 kg is not achievable, because the only available strength is 50 mg. Take mercaptopurine tablets either consistently with or without food.
After initiating mercaptopurine tablets, monitor complete blood count (CBC) and adjust the dose to maintain absolute neutrophil count (ANC) at a desirable level and for excessive myelosuppression. Evaluate the bone marrow in patients with prolonged myelosuppression or repeated episodes of myelosuppression to assess leukemia status and marrow cellularity. Evaluate thiopurine S-methyltransferase (TPMT) and nucleotide diphosphatase (NUDT15) status in patients with severe myelosuppression or repeated episodes or myelosuppression [see Dosage and Administration (2.2)] .
Do not administer to patients who are unable to swallow tablets. If a patient misses a dose, instruct the patient to continue with the next scheduled dose. Mercaptopurine tablets is a cytotoxic drug.
Follow special handling and disposal procedures.
2.2Dosage Modifications in Patients with TPMT and NUDT15 Deficiency Consider testing for TPMT and NUDT15 deficiency in patients who experience severe myelosuppression or repeated episodes of myelosuppression [see Warnings and Precautions (5.1), Clinical Pharmacology (12.5)] . Homozygous Deficiency in either TPMT or NUDT15 Patients with homozygous deficiency of either enzyme typically require 10% or less of the recommended dosage. Reduce the recommended starting dosage of mercaptopurine tablets in patients who are known to have homozygous TPMT or NUDT15 deficiency.
Heterozygous Deficiency in TPMT and/or NUDT15 Reduce the mercaptopurine tablets dose based on tolerability. Most patients with heterozygous TPMT or NUDT15 deficiency tolerate the recommended dosage, but some require a dose reduction based on adverse reactions. Patients who are heterozygous for both TPMT and NUDT15 may require more substantial dose reductions.
2.3Dosage Modifications in Renal and Hepatic Impairment Renal Impairment Use the lowest recommended starting dosage for mercaptopurine tablets in patients with renal impairment (CLcr less than 50 mL/min). Adjust the dosage to maintain absolute neutrophil count (ANC) at a desirable level and for adverse reactions [see Uses in Specific Populations (8.6)] . Hepatic Impairment Use the lowest recommended starting dosage for mercaptopurine tablets in patients with hepatic impairment.
Adjust the dosage to maintain absolute neutrophil count (ANC) at a desirable level and for adverse reactions [see Uses in Specific Populations (8.7)] .
2.4Dosage Modification with Concomitant Use of Allopurinol Reduce the dose of mercaptopurine tablets to one-third to one-quarter of the current dosage when coadministered with allopurinol [see Drug Interactions (7.1)] .
💊 Dosage Forms and Strengths ▾
3 DOSAGE FORMS & STRENGTHS Tablets: 50 mg mercaptopurine, biconvex, round, pale yellow to buff, scored tablets imprinted with “9|3” Tablets: 50 mg (3)
⛔ Contraindications ▾
4 CONTRAINDICATIONS None. None.
⚠️ Warnings and Cautions ▾
5 WARNINGS AND PRECAUTIONS Myelosuppression : Monitor complete blood count (CBC) and adjust the dose of mercaptopurine tablets for excessive myelosuppression. Consider testing in patients with severe myelosuppression or repeated episodes of myelosuppression for thiopurine S -methyltransferase (TPMT) or nucleotide diphosphatase (NUDT15) deficiency. Patients with homozygous or homozygous TPMT or NUDT15 deficiency may require a dose reduction.
(2.2, 5.1) Hepatotoxicity : Monitor transaminases, alkaline phosphatase and bilirubin. Withhold mercaptopurine tablets at onset of hepatotoxicity. (5.2) Immunosuppression : Response to all vaccines may be diminished and there is a risk of infection with live virus vaccines.
Consult immunization guidelines for immunocompromised patients. (5.3) Treatment Related Malignancies : Aggressive and fatal cases of hepatosplenic T-cell lymphoma have occurred. (5.4) Macrophage Activation Syndrome : Monitor for and treat promptly; discontinue mercaptopurine tablets.
(5.5) Embryo-Fetal Toxicity : Can cause fetal harm. Advise patients of reproductive potential of the potential risk to a fetus and to use effective contraception. (5.6, 8.1, 8.3)
5.1Myelosuppression The most consistent, dose-related adverse reaction is myelosuppression, manifested by anemia, leukopenia, thrombocytopenia, or any combination of these. Monitor CBC and adjust the dosage of mercaptopurine tablets for excessive myelosuppression [see Dosage and Administration (2.1)] . Consider testing for TPMT or NUDT15 deficiency in patients with severe myelosuppression or repeated episodes of myelosuppression.
TPMT genotyping or phenotyping (red blood cell TPMT activity) and NUDT15 genotyping can identify patients who have reduced activity of these enzymes. Patients with heterozygous or homozygous TPMT or NUDT15 deficiency may require a dose reduction [see Dosage and Administration (2.2), Clinical Pharmacology (12.5)] . Myelosuppression can be exacerbated by coadministration with allopurinol, aminosalicylates or other products that cause myelosuppression [see Drug Interactions (7.1, 7.3, 7.4)].
Reduce the dose of mercaptopurine tablets when coadministered with allopurinol [see Dosage and Administration (2.4)] .
5.2Hepatoxicity Mercaptopurine is hepatotoxic. There are reports of deaths attributed to hepatic necrosis associated with the administration of mercaptopurine. Hepatic injury can occur with any dosage but seems to occur with greater frequency when the recommended dosage is exceeded.
In some patients, jaundice has cleared following withdrawal of mercaptopurine and reappeared with rechallenge. Usually, clinically detectable jaundice appears early in the course of treatment (1 to 2 months); however, jaundice has been reported as early as 1 week and as late as 8 years after the starting mercaptopurine. The hepatotoxicity has been associated in some cases with anorexia, diarrhea, jaundice, ascites, and pruritus.
Hepatic encephalopathy has occurred. Monitor serum transaminase levels, alkaline phosphatase, and bilirubin levels at weekly intervals when first beginning therapy and at monthly intervals thereafter. Monitor liver tests more frequently in patients who are receiving mercaptopurine tablets with other hepatotoxic products [see Drug Interactions (7.5)] or with known pre-existing liver disease.
Withhold mercaptopurine tablets at onset of hepatotoxicity. Intrahepatic Cholestasis of Pregnancy Postmarketing cases of intrahepatic cholestasis of pregnancy (ICP) have been reported in patients with inflammatory bowel disease who received mercaptopurine during pregnancy. Mercaptopurine is not indicated for use in inflammatory bowel disease [see Indications and Usage (1.1)] .
Discontinue Mercaptopurine if ICP develops in a pregnant woman.
5.3Immunosuppression Mercaptopurine is immunosuppressive and may impair the immune response to infectious agents or vaccines. Due to the immunosuppression associated with maintenance chemotherapy for ALL, respon…
🤒 Adverse Reactions ▾
6 ADVERSE REACTIONS The following clinically significant adverse reactions are described elsewhere in the labeling: Myelosuppression [see Warnings and Precautions (5.1)] Hepatotoxicity [see Warnings and Precautions (5.2)] Immunosuppression [see Warnings and Precautions (5.3)] Treatment related malignancies [see Warnings and Precautions (5.4)] Macrophage activation syndrome [see Warnings and Precautions (5.5)] The most common adverse reaction (>20%) is myelosuppression, including anemia, leukopenia and thrombocytopenia.
Adverse reactions occurring in 5% to 20% of patients include anorexia, nausea, vomiting, diarrhea, malaise and rash. (6.1) To report SUSPECTED ADVERSE REACTIONS, contact Florida Pharmaceutical Products, LLC at 1-800-315-0985 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch
6.1Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. Based on multicenter cooperative group ALL trials, the most common adverse reaction occurring in > 20% of patients was myelosuppression, including anemia, neutropenia, lymphopenia and thrombocytopenia. Adverse reactions occurring in 5% to 20% of patients included anorexia, nausea, vomiting, diarrhea, malaise and rash.
Adverse reactions occurring in < 5 % of patients included urticaria, hyperuricemia, oral lesions, increased transaminases, hyperbilirubinemia, hyperpigmentation, infections, and pancreatitis. Oral lesions resemble thrush rather than antifolic ulcerations. Delayed or late adverse reactions include hepatic fibrosis, hyperbilirubinemia, alopecia, pulmonary fibrosis, oligospermia and secondary malignancies [see Warnings and Precautions (5.1, 5.2)].
Drug fever has been reported with mercaptopurine. Additional adverse reactions that have been reported in patients who have received mercaptopurine include photosensitivity, hypoglycemia, and portal hypertension.
6.2Postmarketing Experience The following adverse reactions have been identified during postapproval use of mercaptopurine tablets. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure. These reactions include: intrahepatic cholestasis of pregnancy (ICP).
🔄 Drug Interactions ▾
7 DRUG INTERACTIONS Allopurinol : Reduce the dose of mercaptopurine tablets when co-administered with allopurinol. (2.4, 7.1) Warfarin : Mercaptopurine tablets may decrease the anticoagulant effect. (7.2)
7.1Allopurinol Allopurinol can inhibit the first-pass oxidative metabolism of mercaptopurine by xanthine oxidase, which can lead to an increased risk of mercaptopurine adverse reactions (i.e., myelosuppression, nausea, and vomiting) [see Warnings and Precautions (5.1), Adverse Reactions (6.1)] . Reduce the dose of mercaptopurine tablets when coadministered with allopurinol [see Dosage and Administration (2.4)] .
7.2Warfarin The concomitant administration of mercaptopurine tablets and warfarin may decrease the anticoagulant effectiveness of warfarin. Monitor the international normalized ratio (INR) in patients receiving warfarin and adjust the warfarin dosage as appropriate.
7.3Myelosuppresive Products Mercaptopurine tablets can cause myelosuppression. Myelosuppression may be increased when mercaptopurine tablets is coadministered with other products that cause myelosuppression. Enhanced myelosuppression has been noted in some patients also receiving trimethoprim-sulfamethoxazole.
Monitor the CBC and adjust the dose of mercaptopurine tablets for excessive myelosuppression [see Dosage and Administration (2.1), Warnings and Precautions (5.1)] .
7.4Aminosalicylates Aminosalicylates (e.g., mesalamine, olsalazine or sulfasalazine) may inhibit the TPMT enzyme, which may increase the risk of myelosuppression when coadministered with mercaptopurine tablets. When aminosalicylates and mercaptopurine tablets are coadministered, use the lowest possible doses for each drug and monitor more frequently for myelosuppression [see Warnings and Precautions (5.1)] .
7.5Hepatotoxic Products Mercaptopurine tablets can cause hepatotoxicity. Hepatotoxicity may be increased when mercaptopurine tablets is coadministered with other products that cause hepatotoxicity. Monitor liver tests more frequently in patients who are receiving mercaptopurine tablets with other hepatotoxic products [see Warnings and Precautions (5.2)] .
👥 Use in Specific Populations ▾
8 USE IN SPECIFIC POPULATIONS Lactation : Advise not to breastfeed. (8.2) Infertility : Can impair fertility. (8.3)
8.1Pregnancy Risk Summary Mercaptopurine tablets can cause fetal harm when administered to a pregnant woman [see Clinical Pharmacology (12.1)] . Pregnant women who receive mercaptopurine have an increased incidence of miscarriage and stillbirth ( see Data ). Advise pregnant women of the potential risk to a fetus.
The estimated background risk of major birth defects and miscarriage for the indicated population(s) is unknown. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2% to 4% and 15% to 20%, respectively.
Data Human Data Women receiving mercaptopurine in the first trimester of pregnancy have an increased incidence of miscarriage; the risk of malformation in offspring surviving first trimester exposure is not known. In a series of 28 women receiving mercaptopurine after the first trimester of pregnancy, 3 mothers died prior to delivery, 1 delivered a stillborn child, and 1 aborted; there were no cases of macroscopically abnormal fetuses. Animal Data Mercaptopurine was embryo-lethal and teratogenic in several animal species (rat, mouse, rabbit, and hamster) at doses less than the recommended human dose.
8.2Lactation Risk Summary There are no data on the presence of mercaptopurine or its metabolites in human milk, the effects on the breastfed child, or the effects on milk production. Because of the potential for serious adverse reactions in the breastfed child, advise women not to breastfeed during treatment with mercaptopurine tablets and for 1 week after the last dose.
8.3Females and Males of Reproductive Potential Mercaptopurine tablets can cause fetal harm when administered to pregnant women [see Use in Specific Populations (8.1)] . Pregnancy Testing Verify the pregnancy status in females of reproductive potential prior to initiating mercaptopurine tablets [see Use in Specific Populations (8.1)] . Contraception Females Advise females of reproductive potential to use effective contraception during treatment with mercaptopurine tablets and for 6 months after the last dose.
Males Based on genotoxicity findings, advise males with female partners of reproductive potential to use effective contraception during treatment with mercaptopurine tablets and for 3 months after the last dose [see Nonclinical Toxicology (13.1)] . Infertility Females and Males Based on findings from animal studies, mercaptopurine tablets can impair female and male fertility [see Nonclinical Toxicology (13.1)] . The long-term effects of mercaptopurine on female and male fertility, including the reversibility have not been studied.
8.4Pediatric Use Safety and effectiveness of mercaptopurine tablets has been established in pediatric patients. Use of mercaptopurine tablets in pediatrics is supported by evidence from the published literature and clinical experience. Symptomatic hypoglycemia has been reported in pediatric patients with ALL receiving mercaptopurine. Reported cases were in pediatrics less than 6 years of age or with a low body mass index.
8.5Geriatric Use Clinical studies of mercaptopurine did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects. Other reported clinical experience has not identified differences in responses between the elderly and younger patients. In general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range, reflecting the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or another drug therapy.
8.6Renal Impairment Use the lowest recommended starting dosage for mercaptopurine tablets or increase the dosing interval to every 36-48 hours in patients wit…
🤰 Pregnancy ▾
8.1Pregnancy Risk Summary Mercaptopurine tablets can cause fetal harm when administered to a pregnant woman [see Clinical Pharmacology (12.1)] . Pregnant women who receive mercaptopurine have an increased incidence of miscarriage and stillbirth ( see Data ). Advise pregnant women of the potential risk to a fetus.
The estimated background risk of major birth defects and miscarriage for the indicated population(s) is unknown. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2% to 4% and 15% to 20%, respectively.
Data Human Data Women receiving mercaptopurine in the first trimester of pregnancy have an increased incidence of miscarriage; the risk of malformation in offspring surviving first trimester exposure is not known. In a series of 28 women receiving mercaptopurine after the first trimester of pregnancy, 3 mothers died prior to delivery, 1 delivered a stillborn child, and 1 aborted; there were no cases of macroscopically abnormal fetuses. Animal Data Mercaptopurine was embryo-lethal and teratogenic in several animal species (rat, mouse, rabbit, and hamster) at doses less than the recommended human dose.
🧒 Pediatric Use ▾
8.4Pediatric Use Safety and effectiveness of mercaptopurine tablets has been established in pediatric patients. Use of mercaptopurine tablets in pediatrics is supported by evidence from the published literature and clinical experience. Symptomatic hypoglycemia has been reported in pediatric patients with ALL receiving mercaptopurine. Reported cases were in pediatrics less than 6 years of age or with a low body mass index.
🧓 Geriatric Use ▾
8.5Geriatric Use Clinical studies of mercaptopurine did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects. Other reported clinical experience has not identified differences in responses between the elderly and younger patients. In general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range, reflecting the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or another drug therapy.
🆘 Overdosage ▾
10 OVERDOSAGE Signs and symptoms of mercaptopurine overdosage may be immediate (anorexia, nausea, vomiting, and diarrhea); or delayed (myelosuppression, liver dysfunction, and gastroenteritis). Dialysis cannot be expected to clear mercaptopurine. Hemodialysis is thought to be of marginal use due to the rapid intracellular incorporation of mercaptopurine into active metabolites with long persistence.
Withhold mercaptopurine tablets immediately for severe or life-threatening adverse reactions occur during treatment. If a patient is seen immediately following an accidental overdosage, it may be useful to induce emesis.
🧬 Clinical Pharmacology ▾
12 CLINICAL PHARMACOLOGY
12.1Mechanism of Action Mercaptopurine is a purine analog that undergoes intracellular transport and activation to form metabolites including thioguanine nucleotides (TGNs). Incorporation of TGNs into DNA or RNA results in cell-cycle arrest and cell death. TGNs and other mercaptopurine metabolites are also inhibitors of de novo purine synthesis and purine nucleotide interconversions.
Mercaptopurine was cytotoxic to proliferating cancer cells in vitro and had antitumor activity in mouse tumor models. It is not known which of the biochemical effects of mercaptopurine and its metabolites are directly or predominantly responsible for cell death.
12.2Pharmacodynamics Exposure-Response Relationships Mercaptopurine exposure-response relationships and the time course of pharmacodynamics response are unknown.
12.3Pharmacokinetics Following a single oral dose of mercaptopurine 50 mg under fasted conditions to adult healthy subjects, the mean AUC 0-INF was 129 h·ng/mL and C max was 69 ng/mL. Absorption Food Effect Food has been shown to decrease the exposure of mercaptopurine. Distribution The volume of distribution usually exceeded that of the total body water.
There is negligible entry of mercaptopurine into cerebrospinal fluid. Plasma protein binding averages 19% over the concentration range 10 to 50 mcg/mL (a concentration only achieved by intravenous administration of mercaptopurine at doses exceeding 5 to 10 mg/kg). Elimination The elimination half-life is less than 2 hours following a single oral dose.
Metabolism Mercaptopurine is inactivated via two major pathways. One is thiol methylation, which is catalyzed by the polymorphic enzyme thiopurine S-methyltransferase (TPMT), to form the inactive metabolite methyl-mercaptopurine. The second inactivation pathway is oxidation, which is catalyzed by xanthine oxidase.
The product of oxidation is the inactive metabolite 6-thiouric acid. Excretion Following the oral administration of radiolabeled mercaptopurine, 46% of the dose was recovered in the urine (as parent drug and metabolites) in the first 24 hours.
12.5Pharmacogenomics Several published studies indicate that patients with reduced TPMT or NUDT15 activity receiving usual doses of mercaptopurine, accumulate excessive cellular concentrations of active 6-TGNs, and are at higher risk for severe myelosuppression. In a study of 1028 children with ALL, the approximate tolerated mercaptopurine dosage for patients with TPMT and/or NUDT15 deficiency on mercaptopurine maintenance therapy (as a percentage of the planned dosage) was as follows: heterozygous for either TPMT or NUDT15, 50-90%; heterozygous for both TPMT and NUDT15, 30-50%; homozygous for either TPMT or NUDT15, 5-10%.
Approximately 0.3% (1:300) of patients of European or African ancestry have two loss-of-function alleles of the TPMT gene and have little or no TPMT activity (homozygous deficient or poor metabolizers), and approximately 10% of patients have one loss-of-function TPMT allele leading to intermediate TPMT activity (heterozygous deficient or intermediate metabolizers). The TPMT*2, TPMT*3A, and TPMT*3C alleles account for about 95% of individuals with reduced levels of TPMT activity. NUDT15 deficiency is detected in <1% of patients of European or African ancestry.
Among patients of East Asian ancestry (i.e., Chinese, Japanese, Vietnamese), 2% have two loss-of-function alleles of the NUDT15 gene, and approximately 21% have one loss-of-function allele. The p.R139C variant of NUDT15 (present on the *2 and *3 alleles) is the most commonly observed, but other less common loss-of-function NUDT15 alleles have been observed. Consider all clinical information when interpreting results from phenotypic testing used to determine the level of thiopurine nucleotides or TPMT activity in erythrocytes, since some coadministered drugs can influence measurement of TPMT activity in blood and blood from recent transfusions will misrepresent a patient’s actual TP…
🧬 Mechanism of Action ▾
12.1Mechanism of Action Mercaptopurine is a purine analog that undergoes intracellular transport and activation to form metabolites including thioguanine nucleotides (TGNs). Incorporation of TGNs into DNA or RNA results in cell-cycle arrest and cell death. TGNs and other mercaptopurine metabolites are also inhibitors of de novo purine synthesis and purine nucleotide interconversions.
Mercaptopurine was cytotoxic to proliferating cancer cells in vitro and had antitumor activity in mouse tumor models. It is not known which of the biochemical effects of mercaptopurine and its metabolites are directly or predominantly responsible for cell death.
📦 How Supplied / Storage and Handling ▾
16 HOW SUPPLIED/STORAGE AND HANDLING Mercaptopurine tablets are supplied as biconvex, round, pale yellow to buff, scored tablets containing 50 mg mercaptopurine, imprinted with “9|3” available in: bottles of 25 NDC 71921-150-02 bottles of 250 NDC 71921-150-25 Store at 20°C to 25°C (68°F to 77°F); excursions permitted to 15°C to 30°C (59°F to 86°F) [see USP Controlled Room Temperature]. Store in a dry place. Dispense in tight container as defined in the USP.
Mercaptopurine tablets is a cytotoxic drug. Follow special handling and disposal procedures.
📋 Description ▾
11 DESCRIPTION Mercaptopurine is a nucleoside metabolic inhibitor, the chemical name is 6H-purine-6-thione, 1,7-dihydro-, monohydrate. The molecular formula is C 5 H 4 N 4 S • H 2 O and the molecular weight is 170.20. Its structural formula is: Mercaptopurine is a yellow, crystalline powder.
Mercaptopurine is practically insoluble in water and in ether. It has a pKa of 7.8, an average tapped density of 1.0 g/mL and average bulk density of 0.85 g/mL. It dissolves in solutions of alkali hydroxides.
Mercaptopurine tablets is available for oral use. Each scored tablet contains 50 mg mercaptopurine and the following inactive ingredients: corn starch, pregelatinized, potato starch, lactose, magnesium stearate and stearic acid. Mercaptopurine-Structure
💬 Information for Patients ▾
17 PATIENT COUNSELING INFORMATION Major Adverse Reactions Advise patients and caregivers that mercaptopurine tablets can cause myelosuppression, hepatotoxicity, and gastrointestinal toxicity. Advise patients to contact their healthcare provider if they experience fever, sore throat, jaundice, nausea, vomiting, signs of local infection, bleeding from any site, or symptoms suggestive of anemia [see Warnings and Precautions (5.1, 5.2, 5.3)] . Embryo-Fetal Toxicity Advise pregnant women of the potential risk to a fetus.
Advise females of reproductive potential to inform their healthcare provider of a known or suspected pregnancy [see Warnings and Precautions (5.2, 5.6), Use in Specific Populations (8.1)] . Advise females of reproductive potential to use effective contraception during treatment with mercaptopurine tablets and for 6 months after the last dose [see Use in Specific Populations (8.3)] . Advise males with female partners of reproductive potential to use effective contraception during treatment with mercaptopurine tablets and for 3 months after the last dose [see Use in Specific Populations (8.3), Nonclinical Toxicology (13.1)] .
Lactation Advise women not to breastfeed during treatment with mercaptopurine tablets and for 1 week after the last dose [see Use in Specific Populations (8.2)] . Infertility Advise males and females of reproductive potential that mercaptopurine tablets can impair fertility [see Use in Specific Populations (8.3)] . Other Adverse Reactions Instruct patients to minimize sun exposure due to risk of photosensitivity [see Adverse Reactions (6.1)] .
Manufactured By: Pinnacle Life Science Pvt. Ltd. Baddi, Solan, HP174101, India Manufactured For: Florida Pharmaceutical Products, LLC Boca Raton, FL 33487 Toll-Free # 1-800-315-0985