Osilodrostat side effects: what 2,082 FDA adverse event reports show

Osilodrostat · Isturisa · 27 reaction terms · 696 drug–reaction co-reports · data 2026-09-14

Drug class

Cortisol synthesis inhibitor

FDA label, Indications wording

Brand names

Isturisa

openFDA label

Who reports

2,082 reports · 68% serious · 270 with death outcome · 73% female

openFDA FAERS counts, all years, deduplication not applied

Used for

ISTURISA is indicated for the treatment of endogenous hypercortisolemia in adults with Cushing's syndrome for whom surgery is not an option or has not been curative. ISTURISA is a cortisol synthesis inhibitor indicated for the treatment of endogenous hypercortisolemia in adults with Cushing's syndrome for whom surgery is not an option or has not been curative ( 1 )

FDA label, Indications and Usage

What it is

ISTURISA (osilodrostat) is a cortisol synthesis inhibitor.

FDA label, Description section

Boxed warning

None in the current label

How to read this page. FAERS is a spontaneous-reporting system: counts are not incidence rates and a signal is not proof of causation. Each reaction below is run through an automated screen — is the term in the FDA label (known), in the indications (the disease being treated), an administrative/coding term, or none of these (unlabeled)? That screen is mechanical text matching, not a causality assessment. The 30 hand-written Bradford Hill assessments are on the causality assessment page. Not medical advice.

Causality screen of the 21 strongest signals

Labeled adverse reaction 3Labeled (related wording) 1Reporting / coding artifact 1Lab value / disease marker 5Not in label — unassessed 11

What the badges mean

Labeled adverse reaction The exact term appears in the label's warnings or adverse-reactions sections: a known, expected effect. The FAERS signal confirms the label rather than discovering anything.
Labeled (related wording) The label describes this effect under different wording (e.g. 'neutropenia' for 'neutrophil count decreased'). Treated as known.
Reporting / coding artifact An administrative, monitoring or exposure term (product issue, off-label use, 'test normal', overdose...). Not a biological reaction; a high PRR here reflects how reports are coded.
Lab value / disease marker A laboratory result, investigation or disease-activity marker (antibody positive, CRP abnormal, swollen joint count) not described in the label. These usually mirror the monitored disease or testing protocol rather than a drug effect; not screened further.
Not in label — unassessed Not found in the label text, not an artifact pattern. This is a genuine candidate for a formal causality assessment (Bradford Hill / WHO-UMC); it has NOT had one here.

Strongest disproportionality signals

Flagged terms (PRR ≥ 2, χ² ≥ 4, n ≥ 10), ranked by PRR; infinite PRRs (no comparator reports) excluded. The EBGM column is a second, shrinkage-based estimate (MGPS) with its 5th percentile EB05 and the BCPNN IC025; a pair flagged by PRR alone is marked PRR-only and should be read as fragile. The strata column recomputes the PRR on serious reports only and flags pairs whose reports are unusually skewed by sex or come mostly from consumers rather than clinicians. 6 further terms are in the interactive explorer. Reaction links open the term's cross-drug page.

Show: hide coding/lab/outcome terms hide indication terms unlabeled only hide PRR-only

Reaction	Reports	PRR 95% CI · ROR · χ²/p	EBGM EB05 · IC025	Label screen	Serious-only & strata	Trial cross-check
Adrenal insufficiency	135	114.9 97.5–135.4ROR 122.8 · χ² 14,960 / p <1e-300	111.8 EB05 96.8 · IC025 +6.0 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 96.2	no trial data cached
Blood potassium increased	37	23.0 16.7–31.7ROR 23.4 · χ² 756 / p 9e-167	22.7 EB05 17.2 · IC025 +3.6 3/3 methods agree	Lab value / disease marker	serious PRR 23.1 · 95% consumer	no trial data cached
Blood potassium decreased	52	17.4 13.3–22.8ROR 17.9 · χ² 789 / p 7e-174	17.3 EB05 13.7 · IC025 +3.5 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 13.9 · 92% consumer	no trial data cached
Blood sodium decreased	29	15.6 10.8–22.3ROR 15.8 · χ² 380 / p 6e-85	15.2 EB05 10.9 · IC025 +3.0 3/3 methods agree	Lab value / disease marker	serious PRR 11.8 · 97% consumer	no trial data cached
Brain fog	17	11.7 7.3–18.9ROR 11.8 · χ² 157 / p 3e-36	10.6 EB05 6.5 · IC025 +2.4 3/3 methods agree	Not in label — unassessed	serious PRR 10.1	no trial data cached
Hyperkalaemia (high potassium)	25	7.2 4.9–10.7ROR 7.3 · χ² 128 / p 6e-30	6.5 EB05 4.6 · IC025 +2.0 3/3 methods agree	Not in label — unassessed	serious PRR 6.2	no trial data cached
Hypokalaemia (low potassium)	32	7.0 5.0–9.9ROR 7.1 · χ² 160 / p 7e-37	6.5 EB05 4.8 · IC025 +2.1 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 6.0 · 91% clinician	no trial data cached
Blood glucose fluctuation	7	6.4 3.1–13.4ROR 6.4 · χ² 27 / p 1e-7	4.7 EB05 2.5 · IC025 +0.9 3/3 methods agree	Lab value / disease marker	serious n=6	no trial data cached
Disease progression	69	5.9 4.7–7.4ROR 6.1 · χ² 277 / p 2e-62	5.7 EB05 4.6 · IC025 +2.1 3/3 methods agree	Reporting / coding artifact	serious PRR 5.0	no trial data cached
Blood glucose decreased	27	5.6 3.9–8.2ROR 5.7 · χ² 99 / p 1e-23	5.2 EB05 3.7 · IC025 +1.7 3/3 methods agree	Labeled (related wording) related wording	serious PRR 6.9 · 100% consumer	no trial data cached
Appendicitis	5	5.4 2.3–13.0ROR 5.4 · χ² 14 / p 1e-4	3.8 EB05 1.8 · IC025 +0.4	Not in label — unassessed	serious PRR 4.6	no trial data cached
Pneumocystis jirovecii pneumonia	5	5.0 2.1–12.1ROR 5.0 · χ² 12 / p 2e-4	3.7 EB05 1.7 · IC025 +0.3	Not in label — unassessed	serious PRR 4.3	no trial data cached
Hepatic cytolysis	6	4.9 2.2–11.0ROR 5.0 · χ² 15 / p 5e-5	3.8 EB05 1.9 · IC025 +0.5	Not in label — unassessed	serious PRR 4.2	no trial data cached
Retching	10	4.7 2.6–8.8ROR 4.8 · χ² 26 / p 2e-7	4.0 EB05 2.3 · IC025 +0.9 3/3 methods agree	Not in label — unassessed	serious PRR 3.9	no trial data cached
Covid-19	72	4.1 3.3–5.1ROR 4.2 · χ² 167 / p 2e-38	4.0 EB05 3.3 · IC025 +1.6 3/3 methods agree	Not in label — unassessed	serious PRR 4.1 · 76% consumer	no trial data cached
Hunger	5	3.7 1.6–9.0ROR 3.8 · χ² 8 / p 0.003	3.0 EB05 1.4 · IC025 +0.0	Not in label — unassessed	serious n=1	no trial data cached
Neoplasm progression	13	3.7 2.2–6.4ROR 3.7 · χ² 23 / p 7e-7	3.4 EB05 2.1 · IC025 +0.8 3/3 methods agree	Not in label — unassessed	serious PRR 4.3	no trial data cached
Blood glucose abnormal	6	3.3 1.5–7.3ROR 3.3 · χ² 7 / p 0.003	2.8 EB05 1.4 · IC025 +0.1	Lab value / disease marker	serious PRR 5.9	no trial data cached
Mood swings	9	2.8 1.5–5.5ROR 2.8 · χ² 9 / p 0.001	2.6 EB05 1.5 · IC025 +0.2	Not in label — unassessed	serious PRR 3.3	no trial data cached
Blood glucose increased	52	2.8 2.1–3.6ROR 2.8 · χ² 58 / p 2e-14	2.7 EB05 2.2 · IC025 +1.0 3/3 methods agree	Lab value / disease marker	serious PRR 4.1 · 90% consumer	no trial data cached
Neoplasm malignant	17	2.6 1.6–4.1ROR 2.6 · χ² 15 / p 6e-5	2.5 EB05 1.6 · IC025 +0.5	Not in label — unassessed	serious PRR 2.2	no trial data cached

Trial evidence (ClinicalTrials.gov)

Trial cross-check not yet run for this drug (ClinicalTrials.gov pull covers the 800 most-reported drugs first).

Most frequently reported reactions

By raw co-report count, regardless of disproportionality. Common terms here are often the illness itself or generic outcomes.

Reaction	Reports	PRR 95% CI · ROR · χ²/p	EBGM EB05 · IC025	Label screen	Serious-only & strata	Trial cross-check
Adrenal insufficiency	135	114.9 97.5–135.4ROR 122.8 · χ² 14,960 / p <1e-300	111.8 EB05 96.8 · IC025 +6.0 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 96.2	no trial data cached
Covid-19	72	4.1 3.3–5.1ROR 4.2 · χ² 167 / p 2e-38	4.0 EB05 3.3 · IC025 +1.6 3/3 methods agree	Not in label — unassessed	serious PRR 4.1 · 76% consumer	no trial data cached
Disease progression	69	5.9 4.7–7.4ROR 6.1 · χ² 277 / p 2e-62	5.7 EB05 4.6 · IC025 +2.1 3/3 methods agree	Reporting / coding artifact	serious PRR 5.0	no trial data cached
Blood glucose increased	52	2.8 2.1–3.6ROR 2.8 · χ² 58 / p 2e-14	2.7 EB05 2.2 · IC025 +1.0 3/3 methods agree	Lab value / disease marker	serious PRR 4.1 · 90% consumer	no trial data cached
Blood potassium decreased	52	17.4 13.3–22.8ROR 17.9 · χ² 789 / p 7e-174	17.3 EB05 13.7 · IC025 +3.5 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 13.9 · 92% consumer	no trial data cached
Wrong technique in product usage process	37	1.8 1.3–2.5ROR 1.9 · χ² 14 / p 1e-4	1.8 EB05 1.4 · IC025 +0.3	Reporting / coding artifact	serious PRR 7.6 · 89% consumer	no trial data cached
Blood potassium increased	37	23.0 16.7–31.7ROR 23.4 · χ² 756 / p 9e-167	22.7 EB05 17.2 · IC025 +3.6 3/3 methods agree	Lab value / disease marker	serious PRR 23.1 · 95% consumer	no trial data cached
Hypokalaemia (low potassium)	32	7.0 5.0–9.9ROR 7.1 · χ² 160 / p 7e-37	6.5 EB05 4.8 · IC025 +2.1 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 6.0 · 91% clinician	no trial data cached
Blood sodium decreased	29	15.6 10.8–22.3ROR 15.8 · χ² 380 / p 6e-85	15.2 EB05 10.9 · IC025 +3.0 3/3 methods agree	Lab value / disease marker	serious PRR 11.8 · 97% consumer	no trial data cached
Blood glucose decreased	27	5.6 3.9–8.2ROR 5.7 · χ² 99 / p 1e-23	5.2 EB05 3.7 · IC025 +1.7 3/3 methods agree	Labeled (related wording) related wording	serious PRR 6.9 · 100% consumer	no trial data cached
Hyperkalaemia (high potassium)	25	7.2 4.9–10.7ROR 7.3 · χ² 128 / p 6e-30	6.5 EB05 4.6 · IC025 +2.0 3/3 methods agree	Not in label — unassessed	serious PRR 6.2	no trial data cached
Neoplasm malignant	17	2.6 1.6–4.1ROR 2.6 · χ² 15 / p 6e-5	2.5 EB05 1.6 · IC025 +0.5	Not in label — unassessed	serious PRR 2.2	no trial data cached
Brain fog	17	11.7 7.3–18.9ROR 11.8 · χ² 157 / p 3e-36	10.6 EB05 6.5 · IC025 +2.4 3/3 methods agree	Not in label — unassessed	serious PRR 10.1	no trial data cached
Acne	14	1.9 1.1–3.1ROR 1.9 · χ² 5 / p 0.015	1.8 EB05 1.2 · IC025 -0.1 PRR-only: not supported by EBGM or IC	Labeled adverse reaction exact term	serious PRR 2.2	no trial data cached
Neoplasm progression	13	3.7 2.2–6.4ROR 3.7 · χ² 23 / p 7e-7	3.4 EB05 2.1 · IC025 +0.8 3/3 methods agree	Not in label — unassessed	serious PRR 4.3	no trial data cached

Unlabeled candidate signals

These flagged terms were not found in the FDA label text and do not match an artifact pattern. They are the pairs that would merit a structured assessment (temporality, dose-response, biological plausibility, consistency across databases, trial or cohort evidence). The screen has not done that; string-matching misses label wording, and a strong PRR can still be stimulated reporting, co-medication, or the disease itself.

Hyperkalaemia — n=25, PRR 7.2
Covid-19 — n=72, PRR 4.1

Want to assess one of these properly? The runbook describes the Bradford Hill / trial-evidence workflow used on the assessment page, and handoff_top1000_signals.csv lists the strongest unassessed pairs across all drugs.

Common questions

What are the most reported side effects of Osilodrostat?

In FDA FAERS, the most frequently co-reported reaction terms for Osilodrostat are adrenal insufficiency, covid-19, blood glucose increased, blood potassium decreased, blood potassium increased, hypokalaemia. These are report counts, not rates: FAERS has no denominator, reporting is voluntary and uneven, and a term can be reported because of the illness being treated rather than the drug.

Does Osilodrostat have an FDA boxed warning?

No. The FDA label retrieved for Osilodrostat has no boxed warning; see the label's Warnings and Precautions for the recognised risks.

Do FAERS signals prove that Osilodrostat causes these side effects?

No. A disproportionality signal (PRR, ROR) means a reaction is reported more often with this drug than with others in the database. That can reflect a real effect, but also the disease being treated, stimulated reporting after news or litigation, co-medications, or how reports are coded. Causality needs temporality, dose-response, biological plausibility, consistency across data sources and, ideally, trial or cohort evidence. This page screens each term against the FDA label and ClinicalTrials.gov results; it does not establish causation.

Sources & methods

FDA label via openFDA (set ID f3a5ec24-63c3-4d83-b1c0-6c550fbe7ae2, effective 20251118; matched on openfda.generic_name.exact:"OSILODROSTAT")
Bayesian shrinkage measures computed offline over all 1,317,300 cached pairs: BCPNN information component (IC, with Norén closed-form IC025) and MGPS empirical-Bayes geometric mean (EBGM, EB05) with a two-component gamma prior fitted by maximum marginal likelihood (α₁=0.57, β₁=0.02, α₂=1.42, β₂=0.70, w=0.17); unstratified
FAERS pair statistics from the OpenPV build of 2026-09-14 (openFDA count= aggregation, field patient.drug.openfda.generic_name.exact, 27 reaction terms, min 3 co-reports); PRR/ROR with 95% CI, chi-square with Yates correction
Serious-only and stratified counts (serious:1, patient.patientsex, primarysource.qualification) from openFDA count queries; serious-only PRR uses the drug serious report total and the term global serious total (N_serious=11,882,979); strata shown only when n ≥ 20
Seriousness and sex counts from openFDA count=serious, patient.patientsex, seriousnessdeath

Page generated 2026-10-08. Label and PubChem text are retrieved automatically and may lag the current label; always check the current prescribing information. OpenPV is a beta research tool of the Open Source Medicine Foundation.