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What the label lists and what reports show

Rituximab side effects

Rituximab's FDA label: “Most common adverse reactions in clinical trials were: NHL (greater than or equal to 25%): infusion-related reactions, fever, lymphopenia, chills, infection, and asthenia ( 6.1 ).” FAERS holds 219,890 reports naming it through July 30, 2026; the reaction reported most often, leaving out the conditions it is used for, product-use terms and outcomes, is pain (18,142 reports).

  • No generic listed
  • Boxed warning

Check it at the source: the rituximab FDA label on DailyMed (effective January 6, 2025, Genentech, Inc.); the FDA FAERS public dashboard.

What does the label list?

From the label: adverse reactions

Most common adverse reactions in clinical trials were: NHL (greater than or equal to 25%): infusion-related reactions, fever, lymphopenia, chills, infection, and asthenia ( 6.1 ).

Table 2 Incidence of Adverse Reactions in greater than or equal to 5% of Patients with Relapsed or Refractory, Low-Grade or Follicular NHL, Receiving Single-agent RITUXAN (N=356) Adverse reactions observed up to 12…

ReactionAll Grades (%)Grade 3 and 4 (%)
Any Adverse Reactions9957
Body as a Whole8610
Fever531
Chills333
Infection314
Asthenia261
Headache191
Abdominal Pain141
Pain121
Back Pain101
Throat Irritation90
Flushing50
Heme and Lymphatic System6748
Lymphopenia4840
Leukopenia144
Neutropenia146
Thrombocytopenia122
Anemia83
Skin and Appendages442
Night Sweats151
Rash151
Pruritus141
Urticaria81
Respiratory System384
Increased Cough131

Rows and numbers as the label prints them, under its own column headings (the first rows of a longer table where it runs on). A reaction in a trial table is not necessarily caused by the medicine, and trials differ from everyday use.

From the label: adverse reactions, continued

The following clinically significant adverse reactions are discussed in greater detail in other sections of the labeling: Infusion-related reactions [see Warnings and Precautions (5.1) ] Severe mucocutaneous reactions [see Warnings and Precautions (5.2) ] Hepatitis B reactivation with fulminant hepatitis [see Warnings and Precautions (5.3) ] Progressive multifocal leukoencephalopathy [see Warnings and Precautions (5.4) ] Tumor lysis syndrome [see Warnings and Precautions (5.5) ] Infections [see Warnings and Precautions (5.6) ] Cardiovascular adverse reactions [see Warnings and Precautions (5.7) ] Renal toxicity [see Warnings and Precautions (5.8) ] Bowel obstruction and perforation [see Warnings and Precautions (5.9) ] Most common adverse reactions in clinical trials were: NHL (greater than or equal to 25%): infusion-related reactions, fever, lymphopenia, chills, infection, and asthenia ( 6.1 ). Pediatric B-NHL/B-AL with chemotherapy (Grade 3 or higher greater than 15%): febrile neutropenia, stomatitis, enteritis, sepsis, alanine aminotransferase increased and hypokalemia ( 6.1 ). CLL (greater than or equal to 25%): infusion-related reactions and neutropenia ( 6.1 ). …

Source: FDA drug label, Genentech, Inc., effective January 6, 2025 (SPL set b172773b-3905-4a1c-ad95-bab4b6126563), via openFDA; the full label on DailyMed

What do FAERS reports show?

219,890 reports list rituximab among the medicines taken, each a report of something that happened, not proof the medicine caused it; 37,918 are coded as a death and 70,125 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. Of the 19 reactions below, 11 are named by the same term (in US spelling) in the label's adverse reactions, warnings or patient leaflet; a reaction the label does not name may still be there under another word, and a report does not show that the medicine caused it.

Reports received each year

The 25 most reported reactions

  • Off Label Use (a use or a product term, not a reaction)45,017
  • Drug Ineffective (a use or a product term, not a reaction)34,372
  • Rheumatoid Arthritis (a use or a product term, not a reaction)20,318
  • Pain18,142
  • Fatigue (named in the label)17,776
  • Rash (named in the label)13,758
  • Arthralgia (named in the label)13,624
  • Pneumonia (named in the label)13,262
  • Infusion Related Reaction (named in the label)13,015
  • Drug Intolerance12,587
  • Nausea (named in the label)12,141
  • Pyrexia (named in the label)12,066
  • Joint Swelling11,993
  • Infection (named in the label)11,193
  • Alopecia10,915
  • Dyspnoea (named in the label)10,846
  • Condition Aggravated (a use or a product term, not a reaction)10,472
  • Abdominal Discomfort10,468
  • Contraindicated Product Administered10,444
  • Headache (named in the label)10,397
  • Intentional Product Use Issue (a use or a product term, not a reaction)10,286
  • Diarrhoea (named in the label)9,924
  • Drug Hypersensitivity9,905
  • Systemic Lupus Erythematosus9,802
  • Treatment Failure (a use or a product term, not a reaction)9,789

Source: FDA Adverse Event Reporting System (FAERS) via openFDA, reports through July 30, 2026; reactions as MedDRA preferred terms

What next?

Rituximab: the full record
label, generics, price, shortages, recalls
Side effects hub
the most reported medicines and reactions