Causality assessment · Causality: well established

Cetuximab and Hypomagnesaemia: is the FAERS signal real?

n=596 co-reports · PRR 30.2 · ROR 30.8

Cetuximab 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.

Causality: well established

Cetuximab ↔ Hypomagnesaemia

n=596 co-reports · PRR 30.2 · ROR 30.8

Cetuximab, an EGFR-targeted cancer drug, damages the kidney's ability to reabsorb magnesium, producing hypomagnesaemia that can be prolonged and require replacement — a physiological consequence of blocking EGFR signalling in the renal tubule, not an idiosyncratic reaction. Because it can be significant and recurrent, magnesium is monitored during therapy. The 596 co-reports (PRR 30.2) reflect both the real effect and the drug's use in head-and-neck and colorectal cancer.

Regulatory basis: cetuximab prescribing information (hypomagnesaemia and electrolyte-monitoring warning). Established EGFR-inhibitor magnesium-wasting literature.

Bradford Hill viewpoint	Status	Note
Temporality (necessary)	met	Magnesium falls during therapy and recovers after withdrawal with replacement
Strength	met	PRR 30 on a moderate co-report count
Consistency	met	Reproduced across EGFR-inhibitor studies
Specificity	met	A recognised EGFR-inhibitor class effect
Biological gradient	met	Dose-related
Plausibility	met	Renal tubular magnesium wasting from EGFR blockade is the mechanism
Coherence	met	Coheres with the labelled electrolyte monitoring
Experiment	partial	Randomized trials recorded magnesium changes by arm
Analogy	met	Analogous to hypomagnesaemia from panitumumab and other EGFR inhibitors

This page's own qualitative read, not an automated/citation-gated assessment.

✓ Trial evidence found — Study of Nivolumab in Combination With Ipilimumab Compared to the Standard of Care (Extreme Regimen) as First Line Treatment in Patients With Recurrent or Metastatic Squamous Cell Carcinoma of the Head and Neck (NCT02741570), N=909

Term (as recorded)	Nivolumab + Ipilimumab (n=468)	EXTREME Regimen (n=441)
Hypomagnesaemia — Metabolism and nutrition disorders	0	2
Hypomagnesaemia — Metabolism and nutrition disorders	34	146

In the EXTREME (cetuximab-containing) regimen of this randomized trial, all-grade hypomagnesaemia was recorded in 146 of 441 patients versus 34 of 468 on the comparator immunotherapy arm — a large excess consistent with cetuximab-induced renal magnesium wasting. View on ClinicalTrials.gov →