mercaptopurine (Rx)

Brand and Other Names:Purinethol, Purixan, more...6Mercaptopurine, 6MP
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Dosing & Uses

AdultPediatric

Dosage Forms & Strengths

tablet

  • 50mg

oral suspension

  • 20mg/mL

Acute Lymphatic Leukemia

Induction: 2.5 mg/kg PO qDay; usually 100-200 mg PO qDay in average adult (other agents preferred)  

May increase by 5 mg/kg/day after 4 weeks

Maintenance: 1.5-2.5 mg/kg PO qDay

Reduce dose by 75% if concomitant allopurinol administration

Reduce dose in renal impairment

Crohn Disease (Off-label)

1-1.5 mg/kg PO qHS

Administration

Take on empty stomach to reduce risk of N/V

Other Information

Monitor: CBC, LFTs

Other Indications & Uses

AML

(Off-label): CML, Crohn's disease, ulcerative colitis, histiocytosis X

Dosage Forms & Strengths

tablet

  • 50mg

oral suspension (Purixan)

  • 20mg/mL

Acute Lymphatic Leukemia

Starting dose: 1.25-2.5 mg/kg (50-75 mg/m²) PO qDay  

Maintenance: 1.5-2.5 mg/kg PO qDay in combination with methotrexate

Reduce dose by 75% if concomitant allopurinol administration

Reduce dose in renal impairment

Administration

Take on empty stomach to reduce risk of N/V

Other Information

Monitor: CBC, LFTs

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Interactions

Interaction Checker

and mercaptopurine

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    Interactions Found

    Contraindicated

      Serious - Use Alternative

        Significant - Monitor Closely

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            Contraindicated (1)

            • febuxostat

              febuxostat increases levels of mercaptopurine by decreasing metabolism. Contraindicated. Potential for increased myelosuppression.

            Serious - Use Alternative (23)

            • adenovirus types 4 and 7 live, oral

              mercaptopurine decreases effects of adenovirus types 4 and 7 live, oral by pharmacodynamic antagonism. Avoid or Use Alternate Drug. Immunosuppressives may diminish therapeutic effects of vaccines and increase risk of adverse effects (increased risk of infection). Live-attenuated vaccines should be avoided for at least 3mo after cessation of immunosuppressive therapy.

            • BCG vaccine live

              mercaptopurine decreases effects of BCG vaccine live by pharmacodynamic antagonism. Avoid or Use Alternate Drug. Immunosuppressants also increase risk of infection with concomitant live vaccines.

            • deferiprone

              deferiprone, mercaptopurine. Either increases toxicity of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Avoid use of deferiprone with other drugs known to be associated with neutropenia or agranulocytosis; if an alternative is not possible, monitor absolute neutrophil count more frequently.

            • human papillomavirus vaccine, nonavalent

              mercaptopurine decreases effects of human papillomavirus vaccine, nonavalent by pharmacodynamic antagonism. Avoid or Use Alternate Drug. Immunosuppressive therapies, including irradiation, antimetabolites, alkylating agents, cytotoxic drugs, and corticosteroids (used in greater than physiologic doses), may reduce the immune responses to vaccines.

            • human papillomavirus vaccine, quadrivalent

              mercaptopurine decreases effects of human papillomavirus vaccine, quadrivalent by pharmacodynamic antagonism. Avoid or Use Alternate Drug. Immunosuppressive therapies, including irradiation, antimetabolites, alkylating agents, cytotoxic drugs, and corticosteroids (used in greater than physiologic doses), may reduce the immune responses to vaccines.

            • influenza virus vaccine quadrivalent, adjuvanted

              mercaptopurine decreases effects of influenza virus vaccine quadrivalent, adjuvanted by pharmacodynamic antagonism. Avoid or Use Alternate Drug. Immunosuppressive drugs may reduce the immune response to influenza vaccine.

            • influenza virus vaccine quadrivalent, intranasal

              mercaptopurine decreases effects of influenza virus vaccine quadrivalent, intranasal by pharmacodynamic antagonism. Avoid or Use Alternate Drug. Immunosuppressants also increase risk of infection with concomitant live vaccines.

            • influenza virus vaccine trivalent, adjuvanted

              mercaptopurine decreases effects of influenza virus vaccine trivalent, adjuvanted by pharmacodynamic antagonism. Avoid or Use Alternate Drug. Immunosuppressive drugs may reduce the immune response to influenza vaccine.

            • measles (rubeola) vaccine

              mercaptopurine decreases effects of measles (rubeola) vaccine by pharmacodynamic antagonism. Avoid or Use Alternate Drug. Immunosuppressants also increase risk of infection with concomitant live vaccines.

            • measles mumps and rubella vaccine, live

              mercaptopurine decreases effects of measles mumps and rubella vaccine, live by pharmacodynamic antagonism. Avoid or Use Alternate Drug. Immunosuppressants also increase risk of infection with concomitant live vaccines.

            • measles, mumps, rubella and varicella vaccine, live

              mercaptopurine decreases effects of measles, mumps, rubella and varicella vaccine, live by pharmacodynamic antagonism. Avoid or Use Alternate Drug. Immunosuppressants also increase risk of infection with concomitant live vaccines.

            • meningococcal A C Y and W-135 polysaccharide vaccine combined

              mercaptopurine decreases effects of meningococcal A C Y and W-135 polysaccharide vaccine combined by pharmacodynamic antagonism. Avoid or Use Alternate Drug. Immunosuppressants also increase risk of infection with concomitant live vaccines.

            • palifermin

              palifermin increases toxicity of mercaptopurine by Other (see comment). Avoid or Use Alternate Drug. Comment: Palifermin should not be administered within 24 hrbefore, during infusion of, or within 24 hr after administration of antineoplastic agents. Coadministration of palifermin within 24 hr of chemotherapy resulted in increased severity and duration of oral mucositis.

            • pneumococcal vaccine 13-valent

              mercaptopurine decreases effects of pneumococcal vaccine 13-valent by pharmacodynamic antagonism. Contraindicated. Immunosuppressants also increase risk of infection with concomitant live vaccines.

            • rotavirus oral vaccine, live

              mercaptopurine decreases effects of rotavirus oral vaccine, live by pharmacodynamic antagonism. Avoid or Use Alternate Drug. Immunosuppressants also increase risk of infection with concomitant live vaccines.

            • smallpox (vaccinia) vaccine, live

              mercaptopurine decreases effects of smallpox (vaccinia) vaccine, live by pharmacodynamic antagonism. Avoid or Use Alternate Drug. Immunosuppressants also increase risk of infection with concomitant live vaccines.

            • tocilizumab

              tocilizumab and mercaptopurine both increase immunosuppressive effects; risk of infection. Avoid or Use Alternate Drug.

            • tofacitinib

              mercaptopurine, tofacitinib. Either increases toxicity of the other by immunosuppressive effects; risk of infection. Avoid or Use Alternate Drug.

            • tongkat ali

              mercaptopurine and tongkat ali both increase immunosuppressive effects; risk of infection. Avoid or Use Alternate Drug.

            • typhoid vaccine live

              mercaptopurine decreases effects of typhoid vaccine live by pharmacodynamic antagonism. Avoid or Use Alternate Drug. Immunosuppressants also increase risk of infection with concomitant live vaccines.

            • varicella virus vaccine live

              mercaptopurine decreases effects of varicella virus vaccine live by pharmacodynamic antagonism. Avoid or Use Alternate Drug. Immunosuppressants also increase risk of infection with concomitant live vaccines.

            • yellow fever vaccine

              mercaptopurine decreases effects of yellow fever vaccine by pharmacodynamic antagonism. Avoid or Use Alternate Drug. Immunosuppressants also increase risk of infection with concomitant live vaccines.

            • zoster vaccine live

              mercaptopurine decreases effects of zoster vaccine live by pharmacodynamic antagonism. Avoid or Use Alternate Drug. Immunosuppressants also increase risk of infection with concomitant live vaccines.

            Monitor Closely (69)

            • acalabrutinib

              acalabrutinib, mercaptopurine. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Coadministration may increase risk of myelosuppressive effects.

            • adalimumab

              adalimumab and mercaptopurine both increase immunosuppressive effects; risk of infection. Use Caution/Monitor.

            • alefacept

              alefacept and mercaptopurine both increase immunosuppressive effects; risk of infection. Use Caution/Monitor.

            • allopurinol

              allopurinol increases levels of mercaptopurine by decreasing metabolism. Use Caution/Monitor. Potential for increased myelosuppression.

            • anakinra

              anakinra and mercaptopurine both increase immunosuppressive effects; risk of infection. Use Caution/Monitor.

            • anthrax vaccine

              mercaptopurine decreases effects of anthrax vaccine by pharmacodynamic antagonism. Use Caution/Monitor. Immunosuppressants also increase risk of infection with concomitant live vaccines.

            • antithymocyte globulin equine

              antithymocyte globulin equine and mercaptopurine both increase immunosuppressive effects; risk of infection. Use Caution/Monitor.

            • antithymocyte globulin rabbit

              antithymocyte globulin rabbit and mercaptopurine both increase immunosuppressive effects; risk of infection. Use Caution/Monitor.

            • astragalus

              mercaptopurine increases and astragalus decreases immunosuppressive effects; risk of infection. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • azathioprine

              azathioprine and mercaptopurine both increase immunosuppressive effects; risk of infection. Use Caution/Monitor.

            • basiliximab

              basiliximab and mercaptopurine both increase immunosuppressive effects; risk of infection. Use Caution/Monitor.

            • belatacept

              belatacept and mercaptopurine both increase immunosuppressive effects; risk of infection. Use Caution/Monitor.

            • canakinumab

              canakinumab and mercaptopurine both increase immunosuppressive effects; risk of infection. Use Caution/Monitor.

            • cholera vaccine

              mercaptopurine decreases effects of cholera vaccine by immunosuppressive effects; risk of infection. Modify Therapy/Monitor Closely. Immunosuppressive therapies, including irradiation, antimetabolites, alkylating agents, cytotoxic drugs and corticosteroids (used in greater than physiologic doses), may reduce the immune response to cholera vaccine.

            • cyclosporine

              cyclosporine and mercaptopurine both increase immunosuppressive effects; risk of infection. Use Caution/Monitor.

            • dengue vaccine

              mercaptopurine decreases effects of dengue vaccine by immunosuppressive effects; risk of infection. Use Caution/Monitor. Immunosuppressive therapies (eg, irradiation, antimetabolites, alkylating agents, cytotoxic drugs, corticosteroids [greater than physiologic doses]) may reduce immune response to dengue vaccine.

            • denosumab

              mercaptopurine, denosumab. Other (see comment). Use Caution/Monitor. Comment: Caution should be taken in patients on concomitant immunosuppressants or with impaired immune systems because of increased risk for serious infections.

            • diphtheria & tetanus toxoids

              mercaptopurine decreases effects of diphtheria & tetanus toxoids by pharmacodynamic antagonism. Use Caution/Monitor. Immunosuppressants also increase risk of infection with concomitant live vaccines.

            • diphtheria & tetanus toxoids/ acellular pertussis vaccine

              mercaptopurine decreases effects of diphtheria & tetanus toxoids/ acellular pertussis vaccine by pharmacodynamic antagonism. Use Caution/Monitor. Immunosuppressants also increase risk of infection with concomitant live vaccines.

            • diphtheria & tetanus toxoids/acellular pertussis/poliovirus, inactivated vaccine

              mercaptopurine decreases effects of diphtheria & tetanus toxoids/acellular pertussis/poliovirus, inactivated vaccine by pharmacodynamic antagonism. Use Caution/Monitor. Immunosuppressants also increase risk of infection with concomitant live vaccines.

            • doxorubicin

              doxorubicin increases toxicity of mercaptopurine by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of hepatotoxicity.

            • doxorubicin liposomal

              doxorubicin liposomal increases toxicity of mercaptopurine by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of hepatotoxicity.

            • echinacea

              mercaptopurine, echinacea. immunosuppressive effects; risk of infection. Use Caution/Monitor. Theoretically echinacea may antagonize the effects of immunosuppressants.

            • etanercept

              etanercept and mercaptopurine both increase immunosuppressive effects; risk of infection. Use Caution/Monitor.

            • everolimus

              everolimus and mercaptopurine both increase immunosuppressive effects; risk of infection. Use Caution/Monitor.

            • fingolimod

              mercaptopurine increases effects of fingolimod by immunosuppressive effects; risk of infection. Modify Therapy/Monitor Closely. Concomitant therapy is expected to increase the risk of immunosuppression. Use caution when switching patients from long-acting therapies with immune effects. .

            • glatiramer

              glatiramer and mercaptopurine both increase immunosuppressive effects; risk of infection. Use Caution/Monitor.

            • golimumab

              golimumab and mercaptopurine both increase immunosuppressive effects; risk of infection. Use Caution/Monitor.

            • haemophilus influenzae type b vaccine

              mercaptopurine decreases effects of haemophilus influenzae type b vaccine by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. Avoid vaccination during chemotherapy or radiation therapy if possible because antibody response might be suboptimal. Patients vaccinated within a 14-day period before starting or during immunosuppressive therapy should be revaccinated =3 months after therapy is discontinued if immune competence has been restored. .

            • hepatitis A vaccine inactivated

              mercaptopurine decreases effects of hepatitis A vaccine inactivated by pharmacodynamic antagonism. Use Caution/Monitor. Immunosuppressants also increase risk of infection with concomitant live vaccines.

            • hepatitis a/b vaccine

              mercaptopurine decreases effects of hepatitis a/b vaccine by pharmacodynamic antagonism. Use Caution/Monitor. Immunosuppressants also increase risk of infection with concomitant live vaccines.

            • hepatitis b vaccine

              mercaptopurine decreases effects of hepatitis b vaccine by pharmacodynamic antagonism. Use Caution/Monitor. Immunosuppressants also increase risk of infection with concomitant live vaccines.

            • hydroxychloroquine sulfate

              hydroxychloroquine sulfate and mercaptopurine both increase immunosuppressive effects; risk of infection. Use Caution/Monitor.

            • hydroxyurea

              mercaptopurine, hydroxyurea. Other (see comment). Use Caution/Monitor. Comment: Combination may increase risk of myelosuppression.

            • infliximab

              infliximab and mercaptopurine both increase immunosuppressive effects; risk of infection. Use Caution/Monitor.

            • influenza A (H5N1) vaccine

              mercaptopurine decreases effects of influenza A (H5N1) vaccine by Mechanism: pharmacodynamic antagonism. Use Caution/Monitor. Immunosuppressive therapies may reduce immune response to H5N1 vaccine.

            • influenza virus vaccine (H5N1), adjuvanted

              mercaptopurine decreases effects of influenza virus vaccine (H5N1), adjuvanted by Mechanism: pharmacodynamic antagonism. Use Caution/Monitor. Immunosuppressive therapies may reduce immune response to H5N1 vaccine.

            • influenza virus vaccine quadrivalent

              mercaptopurine decreases effects of influenza virus vaccine quadrivalent by pharmacodynamic antagonism. Use Caution/Monitor. Immunosuppressants also increase risk of infection with concomitant live vaccines.

            • influenza virus vaccine quadrivalent, cell-cultured

              mercaptopurine decreases effects of influenza virus vaccine quadrivalent, cell-cultured by pharmacodynamic antagonism. Use Caution/Monitor. Immunosuppressants also increase risk of infection with concomitant live vaccines.

            • influenza virus vaccine quadrivalent, recombinant

              mercaptopurine decreases effects of influenza virus vaccine quadrivalent, recombinant by pharmacodynamic antagonism. Use Caution/Monitor. Immune response to vaccine may be decreased in immunocompromised individuals.

            • influenza virus vaccine trivalent

              mercaptopurine decreases effects of influenza virus vaccine trivalent by pharmacodynamic antagonism. Use Caution/Monitor. Immunosuppressants also increase risk of infection with concomitant live vaccines.

            • influenza virus vaccine trivalent, recombinant

              mercaptopurine decreases effects of influenza virus vaccine trivalent, recombinant by pharmacodynamic antagonism. Use Caution/Monitor. Immune response to vaccine may be decreased in immunocompromised individuals.

            • Japanese encephalitis virus vaccine

              mercaptopurine decreases effects of Japanese encephalitis virus vaccine by pharmacodynamic antagonism. Use Caution/Monitor. Immunosuppressants also increase risk of infection with concomitant live vaccines.

            • leflunomide

              leflunomide and mercaptopurine both increase immunosuppressive effects; risk of infection. Use Caution/Monitor.

            • maitake

              mercaptopurine increases and maitake decreases immunosuppressive effects; risk of infection. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • meningococcal group B vaccine

              mercaptopurine decreases effects of meningococcal group B vaccine by pharmacodynamic antagonism. Use Caution/Monitor. Individuals with altered immunocompetence may have reduced immune responses to the vaccine.

            • muromonab CD3

              mercaptopurine and muromonab CD3 both increase immunosuppressive effects; risk of infection. Use Caution/Monitor.

            • mycophenolate

              mercaptopurine and mycophenolate both increase immunosuppressive effects; risk of infection. Use Caution/Monitor.

            • ocrelizumab

              mercaptopurine and ocrelizumab both increase immunosuppressive effects; risk of infection. Use Caution/Monitor. Coadministration of ocrelizumab with immunomodulators is expected to increase the risk of immunosuppression.

            • ofatumumab SC

              ofatumumab SC, mercaptopurine. Either increases effects of the other by immunosuppressive effects; risk of infection. Use Caution/Monitor. Consider the risk of additive immune system effects when coadministering immunosuppressive therapies with coadministration. When switching from therapies with immune effects, take into account the duration and mechanism of action of these therapies when initiating ofatumumab SC.

            • olaparib

              mercaptopurine and olaparib both increase pharmacodynamic synergism. Use Caution/Monitor. Coadministration with other other myelosuppressive anticancer agents, including DNA damaging agents, may potentiate and prolongate the myelosuppressive toxicity.

            • oxaliplatin

              oxaliplatin, mercaptopurine. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Combination may increase risk of myelosuppression.

            • ozanimod

              ozanimod, mercaptopurine. Either increases effects of the other by immunosuppressive effects; risk of infection. Use Caution/Monitor. Coadministration with immunosuppressive therapies may increase the risk of additive immune effects during therapy and in the weeks following administration. When switching from drugs with prolonged immune effects, consider the half-life and mode of action of these drugs in order to avoid unintended additive immunosuppressive effects.

            • pneumococcal vaccine polyvalent

              mercaptopurine decreases effects of pneumococcal vaccine polyvalent by pharmacodynamic antagonism. Use Caution/Monitor. Immunosuppressants also increase risk of infection with concomitant live vaccines.

            • poliovirus vaccine inactivated

              mercaptopurine decreases effects of poliovirus vaccine inactivated by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. Avoid vaccination during chemotherapy or radiation therapy if possible because antibody response might be suboptimal. Patients vaccinated within a 14-day period before starting or during immunosuppressive therapy should be revaccinated =3 months after therapy is discontinued if immune competence has been restored. .

            • rabies vaccine

              mercaptopurine decreases effects of rabies vaccine by pharmacodynamic antagonism. Use Caution/Monitor. Immunosuppressants may interfere with development of active immunity.

            • rabies vaccine chick embryo cell derived

              mercaptopurine decreases effects of rabies vaccine chick embryo cell derived by pharmacodynamic antagonism. Use Caution/Monitor. Immunosuppressants also increase risk of infection with concomitant live vaccines.

            • siponimod

              siponimod and mercaptopurine both increase immunosuppressive effects; risk of infection. Use Caution/Monitor. Caution if coadministered because of additive immunosuppressive effects during such therapy and in the weeks following administration. When switching from drugs with prolonged immune effects, consider the half-life and mode of action of these drugs to avoid unintended additive immunosuppressive effects.

            • sipuleucel-T

              mercaptopurine decreases effects of sipuleucel-T by pharmacodynamic antagonism. Modify Therapy/Monitor Closely.

            • sirolimus

              mercaptopurine and sirolimus both increase immunosuppressive effects; risk of infection. Use Caution/Monitor.

            • tacrolimus

              mercaptopurine and tacrolimus both increase immunosuppressive effects; risk of infection. Use Caution/Monitor.

            • temsirolimus

              mercaptopurine and temsirolimus both increase immunosuppressive effects; risk of infection. Use Caution/Monitor.

            • tetanus toxoid adsorbed or fluid

              mercaptopurine decreases effects of tetanus toxoid adsorbed or fluid by pharmacodynamic antagonism. Use Caution/Monitor. Immunosuppressants also increase risk of infection with concomitant live vaccines.

            • trastuzumab

              trastuzumab, mercaptopurine. Either increases toxicity of the other by immunosuppressive effects; risk of infection. Use Caution/Monitor. Neutropenia or febrile neutropenia incidence were increased when trastuzumab was coadministered with myelosuppressive chemotherapy. .

            • trastuzumab deruxtecan

              trastuzumab deruxtecan, mercaptopurine. Either increases toxicity of the other by immunosuppressive effects; risk of infection. Use Caution/Monitor. Neutropenia or febrile neutropenia incidence were increased when trastuzumab was coadministered with myelosuppressive chemotherapy. .

            • typhoid polysaccharide vaccine

              mercaptopurine decreases effects of typhoid polysaccharide vaccine by pharmacodynamic antagonism. Use Caution/Monitor. Immunosuppressants also increase risk of infection with concomitant live vaccines.

            • ustekinumab

              mercaptopurine and ustekinumab both increase immunosuppressive effects; risk of infection. Use Caution/Monitor.

            • warfarin

              mercaptopurine decreases effects of warfarin by unknown mechanism. Use Caution/Monitor. Inhibition of the anticoagulant effect of warfarin, when given with mercaptopurine, has been reported.

            • zoster vaccine recombinant

              mercaptopurine decreases effects of zoster vaccine recombinant by pharmacodynamic antagonism. Use Caution/Monitor. Immunosuppressive therapies may reduce the effectiveness of zoster vaccine recombinant.

            Minor (5)

            • benazepril

              benazepril, mercaptopurine. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Risk of neutropenia.

            • maitake

              maitake increases effects of mercaptopurine by pharmacodynamic synergism. Minor/Significance Unknown. Maitake mushroom has anti-tumor effects (animal/in vitro research).

            • taurine

              mercaptopurine decreases levels of taurine by unspecified interaction mechanism. Minor/Significance Unknown.

            • vitamin A

              vitamin A, mercaptopurine. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Antioxidants such as vitamin A enhance the efficacy, and reduce toxicity, of antineoplastic drugs.

            • vitamin E

              vitamin E, mercaptopurine. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Antioxidants such as vitamin E enhance the efficacy, and reduce toxicity, of antineoplastic drugs.

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            Adverse Effects

            >10%

            Elevated LFT's (15%)

            1-10%

            Nausea (10%)

            Vomiting (10%)

            Stomatitis (3-10%)

            Thrombocytopenia (3-10%)

            Rash (1-3%)

            Diarrhea (1-3%)

            Dizziness (1-3%)

            Alopecia (1-3%)

            Leukopenia (1-3%)

            Frequency Not Defined

            Fatigue

            Anorexia

            Headache

            Chills and fever

            Chest pain

            Mucositis

            Upper respiratory infection

            Cough

            Ulceration of intestine

            Ulcerative stomatitis

            Myelosuppression

            Decreased hematocrit

            Hepatotoxicity

            Decreased resistance to infections

            Hyperuricemia

            Nephrotoxicity

            Increased risk of pancreatitis in pts with IBD

            Hyperpigmentation of skin

            Arthralgias

            Eye discomfort

            Tinnitus

            Postmarketing Reports

            Photosensitivity

            Hypoglycemia

            Portal hypertension

            Macrophage activation syndrome

            Urticaria

            Hyperbilirubinemia

            Bone marrow toxicity

            Hyperuricemia and/or hyperuricosuria

            Skin rashes and hyperpigmentation

            Alopecia

            Fever (rare)

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            Warnings

            Black Box Warnings

            The drug should not be used unless a diagnosis of acute lymphatic leukemia has been adequately established, and the patient’s physician is knowledgeable in assessing response to chemotherapy

            Contraindications

            Hypersensitivity; prior resistance to 6-MP or thioguanine

            Not effective for CLL, lymphomas, CNS leukemia

            Cautions

            Renal impairment

            Reduce dose by 75% (ie, give quarter dose) when used concurrently with allopurinol

            Recommended that evaluation of hemoglobin or hematocrit, total white blood cell count and differential count, and quantitative platelet count be obtained weekly while patient is on therapy

            Bone marrow examination may be useful for evaluation of marrow status; decision to increase, decrease, continue, or discontinue a given dosage must be based upon degree of severity and rapidity with which changes are occurring; in many instances, particularly during induction phase of acute leukemia, complete blood counts will need to be done more frequently than once weekly in order to evaluate effect of therapy

            Increased risk of bone marrow toxicity; evaluate patients with repeated severe myelosuppression for thiopurine S-methyltransferase (TPMT) or nucleotide diphosphatase (NUDT15) deficiency; TPMT genotyping or phenotyping (red blood cell TPMT activity) and NUDT15 genotyping can identify patients who have reduced activity of these enzymes; patients with homozygous TPMT or NUDT15 deficiency require substantial dosage reductions of the drug

            Increased risk of developing lymphoproliferative disorders and other malignancies, notably skin cancers (melanoma and non-melanoma), sarcomas (Kaposi's and non-Kaposi's) and uterine cervical cancer in situ; increased risk appears to be related to degree and duration of immunosuppression; discontinuation of immunosuppression reported to provide partial regression of lymphoproliferative disorder; a treatment regimen containing multiple immunosuppressants (including thiopurines) should be used with caution as this could lead to lymphoproliferative disorders, some with reported fatalities; a combination of multiple immunosuppressants, given concomitantly increases risk of Epstein-Barr virus (EBV)-associated lymphoproliferative disorders

            Macrophage activation syndrome (MAS) (hemophagocytic lymphohistiocytosis) a life-threatening disorder, may develop in patients with autoimmune conditions, in particular with inflammatory bowel disease (IBD); there could potentially be an increased susceptibility for developing the condition with the use of mercaptopurine (an unapproved use); if MAS occurs, or is suspected, discontinue therapy; monitor for and promptly treat infections such as EBV and cytomegalovirus (CMV), as these are known triggers for MAS

            Drug fever very rarely reported; before attributing fever to drug, make every attempt to exclude more common causes of pyrexia, such as sepsis, in patients with acute leukemia

            Avoid pregnancy

            Hepatosplenic T-cell lymphomas

            • Rare postmarketing cases reported primarily in adolescent and young adult patients with Crohn disease and ulcerative colitis treated with TNF blockers
            • Reports have also included a patient being treated for psoriasis and 2 patients being treated for rheumatoid arthritis
            • HSTCL is an aggressive, rare type of T-cell lymphoma (usually fatal)
            • Most reported cases with TNF blockers have occurred with concomitant treatment with azathioprine or 6-mercaptopurine, although there have been cases reported receiving azathioprine or mercaptopurine alone
            • The following HSTCL cases have been identified in the FDA Adverse Event Reporting System (AERS) database, the literature, and the HSTCL Cancer Survivors' Network: infliximab (20), etanercept (1), adalimumab (2), infliximab/adalimumab (5), certolizumab (0), golimumab (0), azathioprine (12), and mercaptopurine (3)
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            Pregnancy & Lactation

            Pregnancy

            Therapy can cause fetal harm when administered to a pregnant woman; pregnant women who receive mercaptopurine have an increased incidence of miscarriage and stillbirth; advise pregnant women of potential risk to fetus

            Verify pregnancy status in females of reproductive potential prior to initiating therapy

            Reproductive potential

            • Females: Advise females of reproductive potential to use effective contraception during treatment and for 6 months after last dose
            • Males: Based on genotoxicity findings, advise males with female partners of reproductive potential to use effective contraception during treatment with PURIXAN and for 3 months after the last dose

            Infertility

            • Females and males: Based on findings from animal studies, drug can impair female and male fertility; the long-term effects on female and male fertility, including the reversibility have not been studied

            Animal data

            • Drug was embryo-lethal and teratogenic in several animal species (rat, mouse, rabbit, and hamster) at doses less than recommended human dose

            Lactation

            There are no data on presence of mercaptopurine or metabolites in human milk, effects on breastfed child or on milk production; because of potential for serious adverse reactions in breastfed child, advise women not to breastfeed during treatment and for 1 week after last dose

            Pregnancy Categories

            A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.

            B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.

            C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.

            D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.

            X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.

            NA: Information not available.

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            Pharmacology

            Mechanism of Action

            Analog of naturally occurring purines hypoxanthine and guanine

            Purine antagonist, antineoplastic

            Absorption

            Bioavailability: 5-37%

            Peak Plasma Time: 2 hr

            Onset: 2 hr

            Duration: variable

            Distribution

            Protein Bound: 19%

            Vd: 0.56-0.9 L/kg

            Metabolism

            GI mucosa, liver

            Metabolites: 6-thiouric acid

            Elimination

            Half-Life: 21 minutes (children), 47 min (adult)

            Clearance: 11 mL/min/kg

            Excretion: urine

            Dialyzable: no

            Pharmacogenomics

            6-mercaptopurine is activated by guanine phosphoribosyltransferase (HGPRT) to form thioinosine monophosphate (TIMP) and by kinase enzymatic pathways to form active 6-thioguanine nucleotides

            Thiopurine S-methyltransferase (TPMT) inactivates 6-mercaptopurine

            Although complete TPMT deficiency is rare in the general population (0.3%), TPMT screening should be performed prior to administration in all patients prescribed azathioprine or 6-mercaptopurine

            With TPMT deficiency, a larger proportion of 6-mercaptopurine is converted to the cytotoxic 6-thioguanine nucleotide analogues, which can lead to bone marrow toxicity and myelosuppression

            Alleles associated with decreased TPMT enzymatic activity are TPMT*2, TPMT*3A, and TPMT*3C

            Genetic testing laboratories

            • The following companies currently offer testing for TPMT variants
            • Prometheus Labs (http://www.prometheuslabs.com/)
            • Arup Laboratories (http://www.aruplab.com/)
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            Images

            BRAND FORM. UNIT PRICE PILL IMAGE
            Purixan oral
            -
            20 mg/mL suspension
            mercaptopurine oral
            -
            50 mg tablet
            mercaptopurine oral
            -
            50 mg tablet
            mercaptopurine oral
            -
            50 mg tablet

            Copyright © 2010 First DataBank, Inc.

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            Patient Handout

            Patient Education
            mercaptopurine oral

            MERCAPTOPURINE - ORAL

            (mer-KAP-toe-PURE-een)

            COMMON BRAND NAME(S): Purinethol, Purixan

            USES: This medication is used to treat a certain type of cancer (acute lymphocytic leukemia). It is a chemotherapy drug that works by slowing or stopping the growth of cancer cells.Talk to the doctor about the risks and benefits of mercaptopurine, especially when used by children and young adults.

            HOW TO USE: Read the Patient Information Leaflet if available from your pharmacist before you start taking mercaptopurine and each time you get a refill. If you have any questions, ask your doctor or pharmacist.Take this medication by mouth with or without food as directed by your doctor, usually once daily. Drink plenty of fluids while taking this medication unless otherwise directed by your doctor. Doing so may help decrease the risk of certain side effects (kidney problems).If you are using the suspension, shake the bottle well for at least 30 seconds before each dose. Carefully measure the dose using the provided special measuring device. Do not use a household spoon because you may not get the correct dose. Avoid getting any of the suspension on your skin or in your eyes. If contact occurs, wash the affected skin area or rinse your eyes with water. Consult your pharmacist for details.The dosage is based on your medical condition, weight, and response to treatment. Do not increase your dose or use this drug more often or for longer than prescribed. Your condition will not improve any faster, and your risk of serious side effects will increase.Use this medication regularly to get the most benefit from it. To help you remember, take it at the same time each day.Since this drug can be absorbed through the skin and lungs and may harm an unborn baby, women who are pregnant or who may become pregnant should not handle this medication or breathe the dust from the tablets.

            SIDE EFFECTS: Nausea, vomiting, diarrhea, and loss of appetite may occur. Temporary hair loss may also occur. If any of these effects last or get worse, tell your doctor or pharmacist promptly.People using this medication may have serious side effects. However, you have been prescribed this drug because your doctor has judged that the benefit to you is greater than the risk of side effects. Careful monitoring by your doctor may decrease your risk.Tell your doctor right away if you have any serious side effects, including: joint pain/swelling, black stools, vomit that looks like coffee grounds, signs of kidney problems (such as change in the amount of urine, pain in the lower back/side).Get medical help right away if you have any very serious side effects, including: symptoms of liver disease (such as nausea/vomiting that doesn't stop, stomach/abdominal pain, yellowing eyes/skin, dark urine).This medication may decrease bone marrow function, an effect that may lead to a low number of blood cells such as red cells, white cells, and platelets. This effect can cause anemia, decrease your body's ability to fight an infection, or cause easy bruising/bleeding. Tell your doctor right away if you develop any of the following symptoms: unusual tiredness, pale skin, signs of infection (such as sore throat that doesn't go away, fever, chills), easy bruising/bleeding.Mercaptopurine may rarely increase your risk of developing certain types of cancer (such as lymphoma, skin, cervical). This risk is higher in children/young adults being treated for certain bowel diseases (such as Crohn's disease, ulcerative colitis). Keep all medical and laboratory appointments. Tell your doctor right away if you develop any of the following symptoms: swollen abdomen, swollen lymph nodes, night sweats, unexplained weight loss, unusual skin changes (such as new skin lesion or bump, or change in size or color of a mole), unusual vaginal bleeding/discharge.A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), dizziness, trouble breathing.This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.In the US -Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch.In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

            PRECAUTIONS: Before taking mercaptopurine, tell your doctor or pharmacist if you are allergic to it; or to azathioprine; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.Before using this medication, tell your doctor or pharmacist your medical history, especially of: kidney disease, liver disease, cancer, certain enzyme disorders (TPMT deficiency, NUDT15 deficiency).Mercaptopurine can make you more likely to get infections or may worsen any current infections. Avoid contact with people who have infections that may spread to others (such as chickenpox, measles, flu). Consult your doctor if you have been exposed to an infection or for more details.Do not have immunizations/vaccinations without the consent of your doctor. Avoid contact with people who have recently received live vaccines (such as flu vaccine inhaled through the nose).To lower the chance of getting cut, bruised, or injured, use caution with sharp objects like razors and nail cutters, and avoid activities such as contact sports.This medication may make you more sensitive to the sun. Limit your time in the sun. Avoid tanning booths and sunlamps. Use sunscreen and wear protective clothing when outdoors. Tell your doctor right away if you get sunburned or have skin blisters/redness.Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).Since this drug can be absorbed through the skin and lungs and may harm an unborn baby, women who are pregnant or who may become pregnant should not handle this medication or breathe the dust from the tablets.Tell your doctor if you are pregnant or plan to become pregnant. You should not become pregnant while using mercaptopurine. Mercaptopurine may harm an unborn baby, especially during the first 3 months of pregnancy. Your doctor should do a pregnancy test before you start this medication. Women of childbearing age should ask about reliable forms of birth control while using this medication and for 6 months after the last dose. Men with female partners of childbearing age should ask about reliable forms of birth control while using this medication and for 3 months after the last dose. If you or your partner become pregnant, or think you are pregnant, talk to your doctor right away about the risks and benefits of this medication.It is unknown if this drug passes into breast milk. Because of the possible risk to the infant, breast-feeding while using this drug and for 1 week after the last dose is not recommended. Consult your doctor before breast-feeding.

            DRUG INTERACTIONS: Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.Some products that may interact with this drug are: febuxostat, other drugs that weaken the immune system/increase the risk of infection (such as rituximab, tofacitinib).This medication may interfere with certain lab tests (such as uric acid levels), possibly causing false test results. Make sure lab personnel and all your doctors know you use this drug.Mercaptopurine is very similar to azathioprine. Do not use medications containing azathioprine while using mercaptopurine.

            OVERDOSE: If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call their local poison control center at 1-800-222-1222. Canada residents can call a provincial poison control center.

            NOTES: Do not share this medication with others.Lab and/or medical tests (such as complete blood count, liver/kidney function) should be done while you are taking this medication. Keep all medical and lab appointments. Consult your doctor for more details.

            MISSED DOSE: If you miss a dose, take it as soon as you remember. If it is near the time of the next dose, skip the missed dose. Take your next dose at the regular time. Do not double the dose to catch up.

            STORAGE: Store at room temperature away from light and moisture. Do not store in the bathroom. Discard the suspension form of the medication 8 weeks after opening the bottle. Keep all medications away from children and pets.Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company.

            MEDICAL ALERT: Your condition can cause complications in a medical emergency. For information about enrolling in MedicAlert, call 1-888-633-4298 (US) or 1-800-668-1507 (Canada).

            Information last revised August 2021. Copyright(c) 2021 First Databank, Inc.

            IMPORTANT: HOW TO USE THIS INFORMATION: This is a summary and does NOT have all possible information about this product. This information does not assure that this product is safe, effective, or appropriate for you. This information is not individual medical advice and does not substitute for the advice of your health care professional. Always ask your health care professional for complete information about this product and your specific health needs.

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            Formulary

            FormularyPatient Discounts

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            The above information is provided for general informational and educational purposes only. Individual plans may vary and formulary information changes. Contact the applicable plan provider for the most current information.

            Tier Description
            1 This drug is available at the lowest co-pay. Most commonly, these are generic drugs.
            2 This drug is available at a middle level co-pay. Most commonly, these are "preferred" (on formulary) brand drugs.
            3 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs.
            4 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
            5 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
            6 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
            NC NOT COVERED – Drugs that are not covered by the plan.
            Code Definition
            PA Prior Authorization
            Drugs that require prior authorization. This restriction requires that specific clinical criteria be met prior to the approval of the prescription.
            QL Quantity Limits
            Drugs that have quantity limits associated with each prescription. This restriction typically limits the quantity of the drug that will be covered.
            ST Step Therapy
            Drugs that have step therapy associated with each prescription. This restriction typically requires that certain criteria be met prior to approval for the prescription.
            OR Other Restrictions
            Drugs that have restrictions other than prior authorization, quantity limits, and step therapy associated with each prescription.
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            Medscape prescription drug monographs are based on FDA-approved labeling information, unless otherwise noted, combined with additional data derived from primary medical literature.