What the label lists and what reports show
Ganciclovir side effects
Ganciclovir's FDA label: “Most common adverse reactions and laboratory abnormalities reported in at least 20% of patients were: pyrexia, diarrhea, leukopenia, nausea, anemia, asthenia, headache, cough, decreased appetite, dyspnea, abdominal pain, sepsis, hyperhidrosis, and blood …” FAERS holds 10,882 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 cytomegalovirus infection (1,266 reports).
- Generic approved
- Boxed warning
Check it at the source: the ganciclovir FDA label on DailyMed (effective January 9, 2026, Fresenius Kabi USA, LLC); the FDA FAERS public dashboard.
What does the label list?
From the label: adverse reactionsMost common adverse reactions and laboratory abnormalities reported in at least 20% of patients were: pyrexia, diarrhea, leukopenia, nausea, anemia, asthenia, headache, cough, decreased appetite, dyspnea, abdominal pain, sepsis, hyperhidrosis, and blood creatinine increased.
Table 2. Pooled Selected Adverse Reactions Reported in ≥ 5% of Subjects Comparing Ganciclovir for Injection to Ganciclovir Capsules for Maintenance Treatment of CMV Retinitis
| Reaction | Adverse Reaction Ganciclovir for Injection (n=179) | Maintenance Treatment Studies Ganciclovir Capsules (n=326) |
|---|---|---|
| Pyrexia | 48% | 38% |
| Diarrhea | 44% | 41% |
| Leukopenia | 41% | 29% |
| Anemia | 25% | 19% |
| Total catheter events | 22% | 6% |
| Catheter infection | 9% | 4% |
| Catheter sepsis | 8% | 1% |
| Other catheter related events | 5% | 1% |
| Sepsis | 15% | 4% |
| Decreased appetite | 14% | 15% |
| Vomiting | 13% | 13% |
| Infection | 13% | 9% |
| Hyperhidrosis | 12% | 11% |
| Chills | 10% | 7% |
| Neuropathy peripheral | 9% | 8% |
| Thrombocytopenia | 6% | 6% |
| Pruritus | 5% | 6% |
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 serious adverse reactions are discussed in greater detail in other sections of the labeling: • Hematologic Toxicity [see Warnings and Precautions ( 5.1 )] • Renal Impairment [see Warnings and Precautions ( 5.2 )] • Impairment of Fertility [see Warnings and Precautions ( 5.3 )] • Fetal Toxicity [see Warnings and Precautions ( 5.4 )] • Mutagenesis and Carcinogenesis [see Warnings and Precautions ( 5.5 )] Most common adverse reactions and laboratory abnormalities reported in at least 20% of patients were: pyrexia, diarrhea, leukopenia, nausea, anemia, asthenia, headache, cough, decreased appetite, dyspnea, abdominal pain, sepsis, hyperhidrosis, and blood creatinine increased. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Fresenius Kabi USA, LLC at 1-800-5517176 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. 6.1 Clinical Trials Experience in Adult Patients 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 rates observed in practice. …
Source: FDA drug label, Fresenius Kabi USA, LLC, effective January 9, 2026 (SPL set 35addab5-09db-4f8a-9c69-6fbce33ecc37), via openFDA; the full label on DailyMed
What do FAERS reports show?
10,882 reports list ganciclovir among the medicines taken, each a report of something that happened, not proof the medicine caused it; 3,390 are coded as a death and 4,437 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 20 reactions below, 9 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?
- Ganciclovir: 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