What the label lists and what reports show
Rasburicase side effects
Rasburicase's FDA label: “Most common adverse reactions (incidence ≥20%), when used concomitantly with anticancer therapy are vomiting, nausea, fever, peripheral edema, anxiety, headache, abdominal pain, constipation, diarrhea, hypophosphatemia, pharyngolaryngeal pain, and increased …” FAERS holds 2,410 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 tumour lysis syndrome (356 reports).
- No generic listed
- Boxed warning
Check it at the source: the rasburicase FDA label on DailyMed (effective July 30, 2026, Sanofi-Aventis U.S. LLC); the FDA FAERS public dashboard.
What does the label list?
From the label: adverse reactionsMost common adverse reactions (incidence ≥20%), when used concomitantly with anticancer therapy are vomiting, nausea, fever, peripheral edema, anxiety, headache, abdominal pain, constipation, diarrhea, hypophosphatemia, pharyngolaryngeal pain, and increased alanine aminotransferase.
Table 1: Per-Patient Incidence of Selected Adverse Reactions by Study Arm in Study 4
| Reaction | All Grades % | Grades 3,4 % | All Grades % | Grades 3,4 % | All Grades % | Grades 3,4 % |
|---|---|---|---|---|---|---|
| Nausea | 57.6 | 1.1 | 60.9 | 1.1 | 54.9 | 2.2 |
| Peripheral edema | 50 | 2.2 | 43.5 | 3.3 | 42.9 | 6.6 |
| Vomiting | 38 | 1.1 | 37 | 0 | 30.8 | 1.1 |
| Anxiety | 23.9 | 3.3 | 17.4 | 0 | 17.6 | 0 |
| Abdominal pain | 21.7 | 3.3 | 33.7 | 4.3 | 25.3 | 2.2 |
| Hypophosphatemia | 17.4 | 4.3 | 22.8 | 6.5 | 16.5 | 6.6 |
| Hyperbilirubinemia | 16.3 | 3.3 | 14.1 | 2.2 | 7.7 | 4.4 |
| Pharyngolaryngeal pain | 14.1 | 1.1 | 20.7 | 0 | 9.9 | 0 |
| Sepsis | 12 | 5.4 | 7.6 | 6.5 | 4.4 | 4.4 |
| Fluid overload | 12 | 0 | 6.5 | 0 | 3.3 | 1.1 |
| Increased alanine aminotransferase | 10.9 | 3.3 | 27.2 | 4.3 | 17.6 | 2.2 |
| Hyperphosphatemia | 9.8 | 0 | 15.2 | 0 | 8.8 | 1.1 |
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, continuedThe following clinically significant adverse reactions are discussed in greater detail in other sections of the prescribing information: Anaphylaxis [see Boxed Warning, Contraindications (4), Warnings and Precautions (5.1) ] Hemolysis [see Boxed Warning, Contraindications (4), Warnings and Precautions (5.2) ] Methemoglobinemia [see Boxed Warning, Contraindications (4), Warnings and Precautions (5.3) ] Most common adverse reactions (incidence ≥20%), when used concomitantly with anticancer therapy are vomiting, nausea, fever, peripheral edema, anxiety, headache, abdominal pain, constipation, diarrhea, hypophosphatemia, pharyngolaryngeal pain, and increased alanine aminotransferase. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact sanofi-aventis U.S. LLC at 1-800-633-1610 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. 6.1 Clinical 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. The data below reflect exposure to Elitek in 265 pediatric and 82 adult patients enrolled in one active-controlled trial (Study 1), two uncontrolled trials (Studies 2 and 3), and an uncontrolled safety trial (n=82). …
Source: FDA drug label, Sanofi-Aventis U.S. LLC, effective July 30, 2026 (SPL set 0ae10bc4-6b65-402f-9db5-2d7753054922), via openFDA; the full label on DailyMed
What do FAERS reports show?
2,410 reports list rasburicase among the medicines taken, each a report of something that happened, not proof the medicine caused it; 659 are coded as a death and 1,295 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 21 reactions below, 7 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
Source: FDA Adverse Event Reporting System (FAERS) via openFDA, reports through July 30, 2026; reactions as MedDRA preferred terms
What next?
- Rasburicase: the full record
- label, generics, price, shortages, recalls
- Report a side effect to the FDA
- MedWatch
- Side effects hub
- the most reported medicines and reactions