Causality assessment · Expected pharmacological effect

Hydroxyurea and Febrile neutropenia: is the FAERS signal real?

n=426 co-reports · PRR 6.5 · ROR 6.6

Hydroxyurea side-effect profile All assessments See in the full list

A written Bradford Hill assessment of one drug–event pair. The grade is a judgement about the signal, not a statement that this drug causes this event in any one person; FAERS counts are reports, not rates.

Expected pharmacological effect

Hydroxyurea ↔ Febrile neutropenia

n=426 co-reports · PRR 6.5 · ROR 6.6

Hydroxyurea suppresses the marrow and can cause neutropenia with fever, which is dose-limiting in some regimens; 426 co-reports give PRR 6.5. The label advises regular blood-count monitoring and interruption for marked cytopenia.

Regulatory basis: hydroxyurea prescribing information — myelosuppression; blood-count monitoring.

Bradford Hill viewpoint	Status	Note
Temporality (necessary)	met	Weeks of therapy
Strength	met	PRR 6.5 with 426 co-reports
Consistency	met	Consistent across cohorts
Specificity	not established	Neutropenic fever has many causes
Biological gradient	met	Dose-related
Plausibility	met	Known ribonucleotide-reductase inhibition
Coherence	met	Fits hydroxyurea myelosuppression
Experiment	n/a	Often coded in trials
Analogy	met	Analogous to other antimetabolite cytopenias

This table is this page's own qualitative read of the literature cited above, not an automated or citation-gated assessment — see the note at the bottom of this page.

✓ Trial evidence found — A Phase 1/2 Study of CPI-0610 With and Without Ruxolitinib in Patients With Hematologic and Myeloproliferative Malignancies (NCT02158858)

Adverse event	Phase 1 (24 mg Capsule PO Daily) (n=3) · Phase 1 (48 mg Capsule PO Daily) (n=5) · Phase 1 (120 mg Capsule PO Daily) (n=5) · Phase 1 (170 mg Capsule PO Daily) (n=3)
Febrile neutropenia	1/3	2/5	1/5	0/3

Post-marketing signal terms appear in this trial's posted adverse-event tables; per-arm counts shown as affected/at-risk. View on ClinicalTrials.gov →