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allopurinol

Sold as Aloprim, Zyloprim. Class: Preparations inhibiting uric acid production. First FDA approval 08/19/1966: 60 years on the US market.

This grade answers one narrow question: how strong is the public evidence and safety record behind this drug, and how clean is its money trail and court record? It is not a verdict on whether the drug is right for you.

B

Score breakdown (78/100)

Safety ×35%
C
Evidence ×25%
C
Regulatory ×15%
B
Money & lawsuits ×15%
A
Options ×10%
A

Safety: 65

Evidence: 72

Regulatory history: 86

Money & lawsuits: 100

Options: 90

FDA boxed warning

BOXED WARNING

Independent reviews and post-approval warnings

WHO Essential Medicine

Listed on the WHO Model List of Essential Medicines: a global expert panel judged it among the medicines a health system should always have, on evidence of value, not marketing.

What the FDA label says

Approved uses

Allopurinol tablets are indicated for: The management of adults with signs and symptoms of primary or secondary gout (acute attacks, tophi, joint destruction, uric acid lithiasis, and/or nephropathy) The management of adult and pediatric patients with leukemia, lymphoma and solid tumor malignancies who are receiving cancer therapy which causes elevations of serum and urinary uric acid levels The management of adult patients with recurrent calcium oxalate calculi whose daily uric acid excretion exceeds 800 mg/day in male patients and 750 mg/day in female patients, despite lifestyle changes (such as reduction of dietary sodium, non-dairy animal protein, oxylate rich foods, refined sugars and increases in oral fluids and fruits and vegetables) Limitations of Use Allopurinol tablets are not recommended for the treatment of asymptomatic hyperuricemia. Allopurinol tablets are a xanthine oxidase inhibitor indicated for the management of: Adult patients with signs and symptoms of primary or secondary gout (acute attacks, tophi, joint destruction, uric acid lithiasis, and/or nephropathy) ( 1 ) Adult and pediatric patients with leukemia, lymphoma and solid tumor malignancies who are receivin...

Contraindications

Allopurinol tablets are contraindicated in patients with a history of hypersensitivity reaction to allopurinol or to any of the ingredients of allopurinol tablets. Known hypersensitivity to allopurinol or to any of the ingredients of allopurinol tablets.

Warnings and precautions

Skin Rash and Hypersensitivity: Allopurinol has been associated with serious and sometimes fatal dermatological reactions. Discontinue allopurinol tablets at the first appearance of skin rash or other signs of hypersensitivity reaction. ( 5.1 ) Gout Flares: May occur during initiation of treatment. Concurrent prophylactic treatment with colchicine or anti-inflammatory agents is recommended. ( 5.2 ) Nephrotoxicity: Allopurinol may affect kidney function. Patients with decreased kidney function require lower doses of allopurinol tablets. ( 5.3 ) Hepatoxicity: Cases of reversible hepatotoxicity have occurred. If signs and symptoms of hepatotoxicity develop, evaluate liver function. ( 5.4 ) Myelosuppression: Bone marrow suppression has been reported with allopurinol. ( 5.5 ) Potential Effect on Driving and Use of Machinery: Drowsiness, somnolence and dizziness have been reported in patients taking allopurinol tablets. ( 5.6 ) 5.1 Skin Rash and Hypersensitivity Serious and sometimes fatal dermatologic reactions, including toxic epidermal necrolysis (TEN), Stevens-Johnson syndrome (SJS), and drug reaction with eosinophilia and systemic symptoms (DRESS) have been reported in patients taki...

Adverse reactions (label)

The following clinically significant adverse reactions are described elsewhere in the labeling: Skin Rash and Hypersensitivity [see Warnings and Precautions ( 5.1 )] Nephrotoxicity [see Warnings and Precautions ( 5.3 )] Hepatoxicity [see Warnings and Precautions ( 5.4 )] Myelosuppression [see Warnings and Precautions ( 5.5 )] Potential Effect on Driving and Use of Machinery [see Warnings and Precautions ( 5.6 )] The following adverse reactions associated with the use of allopurinol tablets were identified in literature, unpublished clinical trials or postmarketing reports. Because some of these reactions were 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. The most frequent adverse reaction to allopurinol tablets is skin rash. Most Common Adverse Reactions (≥ 1%) Gastrointestinal : Diarrhea, nausea, alkaline phosphatase increase, AST/ALT increase. Metabolic and Nutritional : Acute attacks of gout. Skin and Appendages : Rash, maculopapular rash. Less Common Adverse Reactions (< 1%) Body As a Whole : Ecchymosis, fever, headache, malaise. Cardiovascular : Necro...

Source: FDA SPL label for Allopurinol (Bryant Ranch Prepack), effective 20240708. Full label on DailyMed.

Side-effect reports sent to the FDA

These are counts of reports people filed, not rates of harm. Anyone can file one, and nobody checks whether the drug was the cause. Millions of doses are taken for every report sent, so the useful part is how this drug compares with the average across all drugs.

136,853reports that mention this drug
136,283of those blame this drug, not another one the person was taking
83%of reports describe a serious outcome, such as a hospital stay (average for all drugs: 57%)
13.7%of reports include a death, from any cause (average for all drugs: 9.1%)

Problems reported most often

Diarrhoea · 7,749Fatigue · 7,529Acute Kidney Injury · 7,523Off Label Use · 6,988Dyspnoea · 6,882Death · 6,605Nausea · 6,283Pyrexia · 5,183Pneumonia · 5,103Asthenia · 4,818Anaemia · 4,736Drug Ineffective · 4,629Dizziness · 4,367Fall · 4,127Renal Failure · 3,791

Reports per year

20192020202120222023202420252026
14,83314,41512,13110,9389,4429,1529,2264,327

2,314 reports blaming this drug for every million Medicare prescriptions filled, which is 0.8× the typical drug on this site. (22,472 reports in 2024–2026, against 9,710,041 Medicare fills in one year. This is the one number here that accounts for how many people take the drug.)

Source: the FDA's Adverse Event Reporting System (FAERS). Reports are voluntary and unverified. Drugs that are prescribed a lot, in the news, or in lawsuits attract more reports, so the percentages are compared with the whole database to correct for that partly, not fully.

Recalls and regulatory record

5recall actions on file
7 / 24brand / generic applications
10label changes since 2021
NoREMS program
DateClassFirmReason
06/2024Class IIDr. Reddy's Laboratories, Inc.Presence of foreign substance.
01/2023Class IIAccord Healthcare, Inc.Presence of Foreign Substance: Presence of a small piece of green plastic embedded in the crack towards the edge of the tablet.
01/2022Class IICARDINAL HEALTHCARECGMP Deviations: Products were exposed to temperatures outside of the products labeled storage conditions.
05/2020Class IIMylan Institutional LLCDiscoloration: Out-of-specification results for appearance obtained during routine stability testing at the end of shelf-life for the parameters Appearance and Color of Solution.
07/2015Class IIIQualitest PharmaceuticalsFailed Tablet/Capsule Specifications; report of oversized and discolored tablets

Class I = reasonable probability of serious harm. Class II = temporary or reversible harm. Class III = unlikely to harm. Most generic recalls are manufacturing or labeling defects for one lot, not a verdict on the molecule.

Evidence base

281randomized trials (PubMed)
68systematic reviews
227registered trials
47%of completed trials posted results
11%terminated or withdrawn
35%industry-funded

Independent Cochrane reviews

Counts measure how much evidence exists and how transparent it is, not how big the benefit is. For that, ask your prescriber: if 100 people like me took this, how many would get better because of it, and how many would be harmed? (Doctors call these the "number needed to treat" and "number needed to harm.") It differs by condition and is the number drug ads leave out. Sources: PubMed, ClinicalTrials.gov.

Money and lawsuits

In 2024, drug companies reported $0 in payments to US physicians and hospitals tied to this drug across 0 transactions.

No pending federal MDL names this drug or its brands.

Not named in any federal pharmaceutical settlement of $100M or more on record.

Sources: CMS Open Payments (Sunshine Act); Judicial Panel on Multidistrict Litigation pending docket list; DOJ settlements as tabulated on Wikipedia with links to the primary record. State-court and individual suits are not included.

Who takes it and what it costs

2,355,824Medicare Part D patients (2024)
9,710,041prescriptions filled
$10average cost per fill
$96Mtotal Medicare spend

Same-class alternatives

febuxostattisopurine

Same ATC pharmacological class, graded ones first, best grade at the top. Being in the same class does not make them interchangeable for your condition; it makes them worth asking about.

Questions to ask your prescriber

  1. This drug carries a boxed warning. Which specific risk does it cover, and does it apply to me?
  2. The most-reported problems in FDA's adverse event data are diarrhoea, fatigue, acute kidney injury. How would we recognize and handle those?
  3. Off-label use is among the most-reported items for this drug. Is my use on-label, and if not, what evidence supports it?
  4. Why this one over febuxostat, tisopurine? What would make you pick one of those instead?
  5. What result are we expecting, by when, and what is the plan if it does not happen?
  6. If 100 people like me took this drug, how many would actually get better because of it, and how many would be harmed by it? (Doctors call these the number needed to treat and the number needed to harm.)