Mercaptopurine Brand names: Purixan; first approved as Purinethol

What is mercaptopurine used for?

From the label: indications and usage

MERCAPTOPURINE is a nucleoside metabolic inhibitor indicated for the treatment of patients with acute lymphoblastic leukemia (ALL) as part of a combination chemotherapy maintenance regimen. ( 1.1 ) 1.1 Acute Lymphoblastic Leukemia MERCAPTOPURINE is indicated for the treatment of patients with acute lymphoblastic leukemia (ALL) as part of a combination chemotherapy maintenance regimen.

Conditions named in the indications of mercaptopurine's FDA labels, with every medicine labeled for each:

• Leukemia, lymphoma and myeloma

FDA pharmacologic class: Nucleoside Metabolic Inhibitor.

What does the patient leaflet for mercaptopurine say first?

The FDA-approved Medication Guide or Patient Information that comes with the medicine, in its own words.

From the patient leaflet: What should I avoid while taking MERCAPTOPURINE?

MERCAPTOPURINE can make your skin more sensitive to sunlight. Protect yourself from sunlight during treatment with MERCAPTOPURINE.

From the patient leaflet: How should I store MERCAPTOPURINE?

MERCAPTOPURINE comes in a bottle with a child-resistant cap. Store MERCAPTOPURINE between 59ºF to 77ºF (15ºC to 25ºC), in a dry place. Do not store above 25°C. Store the oral dispensing syringe in a clean place, with the medicine. MERCAPTOPURINE oral suspension should be used within 8 weeks after opening the bottle. Dispose of (throw away) any unused medicine after 8 weeks. Do not use after the expiry date which is stated on the carton and the bottle after ‘EXP’. Keep the bottle tightly closed to prevent spoilage of the medicine and reduce the risk of accidental spillage. Keep MERCAPTOPURINE out of the reach of children, preferably in a locked cupboard. If a child accidentally takes MERCAPTOPURINE, it could cause death.

Is there a generic for mercaptopurine (Purinethol)?

The FDA approved the first generic mercaptopurine on February 11, 2004. 4 generic applications are approved; 3 of them carry a current (not discontinued) marketing status in Drugs@FDA; that status is not evidence that the generic is on sale.

FDA's NDC Directory lists mercaptopurine from 2 labelers under a generic (ANDA) application and from 2 brand labelers. A listing means the company has registered the product for sale; it does not show that every pharmacy stocks it.

What do pharmacies pay for mercaptopurine (Purinethol)?

In CMS's NADAC survey of October 7, 2026, pharmacies paid $1.07 per Mercaptopurine 50 mg tablet, down 7% from $1.16 on October 8, 2025. The chart's scale runs from the lowest to the highest price shown, not from zero. NADAC is what retail pharmacies paid their wholesalers, per unit, in CMS's monthly survey; what a patient pays depends on insurance and the pharmacy.

Has mercaptopurine been recalled?

The FDA's Enforcement Report lists 6 recalls naming mercaptopurine since 2012: 0 Class I (the most serious), 4 Class II, 2 Class III; 0 still ongoing. A recall names products and lots, not every product of the medicine.

What does the mercaptopurine label say about other medicines?

The mercaptopurine label names 5 other medicines in its interaction, contraindication or warning sections. The labels of 9 other medicines name mercaptopurine. The sentences are the labels' own; a label lists what its studies and reports found, not every interaction.

Other labels that name mercaptopurine

• Adalimumab-fkjp
• Febuxostat
• Natalizumab

Check mercaptopurine against other medicines

What do FAERS reports show for mercaptopurine?

The FDA Adverse Event Reporting System holds 17,961 reports that list mercaptopurine among the medicines taken, through July 30, 2026, each a report of something that happened, not proof the medicine caused it; 1,979 are coded as a death and 7,995 as a hospital stay. Counts follow how widely a medicine is used and watched, and they are not a measure of how risky it is.

Reports received each year

• 928
• 1,155
• 1,318
• 1,277
• 1,187
• 1,378
• 1,435
• 1,287
• 1,190
• 858
• 394

• 2016
• 2017
• 2018
• 2019
• 2020
• 2021
• 2022
• 2023
• 2024
• 2025
• 2026

The most reported reactions

• Febrile Neutropenia1,923
• Off Label Use (a use or a product term, not a reaction)1,380
• Pyrexia1,225
• Drug Ineffective (a use or a product term, not a reaction)1,117
• Nausea (named in the label)815
• Vomiting (named in the label)783
• Abdominal Pain719
• Diarrhoea (named in the label)716

Side effects: the label's list and every FAERS reaction

What else is labeled for the same conditions as mercaptopurine?

37 other medicines are given the same way (oral) and in the same FDA class as mercaptopurine or labeled mainly for the same use (leukemia, lymphoma and myeloma), the same class first. Leukemia, lymphoma and myeloma lists all 98 medicines labeled for it, by any route. The first 8 are below. They are listed as records, not as substitutes: whether one can replace another is a prescriber's decision.

Every medicine labeled for the same conditions as mercaptopurine

What next?

Alternatives to mercaptopurine

37 medicines for the same use

Other nucleoside metabolic inhibitors

the pharmacologic class, with prices and generics

Mercaptopurine side effects

the label's list beside FAERS reports

Check an interaction

what two or more labels say about each other