Drug · FAERS side-effect profile with label screen
Megestrol side effects: what 3,838 FDA adverse event reports show
Drug class
Not stated in label
Label matched
Megestrol Acetate (Megestrol Acetate)
closest FDA label found for this product string; brand list suppressed because the label is a related product, not an exact match
Who reports
3,838 reports · 80% serious · 956 with death outcome · 46% female
openFDA FAERS counts, all years, deduplication not applied
Used for
Megestrol acetate oral suspension, USP is indicated for the treatment of anorexia, cachexia, or an unexplained, significant weight loss in patients with a diagnosis of acquired immunodeficiency syndrome (AIDS).
FDA label, Indications and Usage
What it is
DESCRIPTION Megestrol Acetate Oral Suspension, USP contains megestrol acetate, a synthetic derivative of the steroid hormone, progesterone. Megestrol acetate is a white, crystalline solid chemically designated as 17-Hydroxy-6-methylpregna-4,6-diene-3,20-dione acetate.
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 40 strongest signals
Labeled adverse reaction 2Labeled (related wording) 2Likely indication confounding 1Reporting / coding artifact 1Lab value / disease marker 2Not in label — unassessed 32
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.
- Likely indication confounding The term appears in the label's indications: reports probably describe the disease being treated (or its progression), not a drug effect. Classic confounding by indication.
- 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. 232 further terms are in the interactive explorer. Reaction links open the term's cross-drug page.
Show:
| Reaction | Reports | PRR 95% CI · ROR · χ²/p | EBGM EB05 · IC025 | Label screen | Serious-only & strata | Trial cross-check |
|---|---|---|---|---|---|---|
| Adrenal insufficiency | 65 | 29.8 23.4–37.9ROR 30.3 · χ² 1,771 / p <1e-300 | 29.4 EB05 23.9 · IC025 +4.2 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 21.7 · 95% clinician | no trial data cached |
| Atelectasis | 23 | 13.0 8.6–19.5ROR 13.0 · χ² 242 / p 8e-55 | 12.3 EB05 8.2 · IC025 +2.7 3/3 methods agree | Not in label — unassessed | serious PRR 9.5 | no trial data cached |
| Economic problem | 32 | 11.4 8.0–16.0ROR 11.4 · χ² 291 / p 1e-65 | 10.8 EB05 7.8 · IC025 +2.7 3/3 methods agree | Reporting / coding artifact | serious PRR 8.7 | no trial data cached |
| End stage renal disease | 33 | 9.8 7.0–13.8ROR 9.9 · χ² 252 / p 6e-57 | 9.2 EB05 6.7 · IC025 +2.5 3/3 methods agree | Not in label — unassessed | serious PRR 7.1 | no trial data cached |
| Prostatic specific antigen increased | 24 | 9.5 6.4–14.1ROR 9.5 · χ² 173 / p 7e-40 | 8.6 EB05 5.9 · IC025 +2.3 3/3 methods agree | Lab value / disease marker | serious PRR 8.9 · ♀ 0% (drug 46%) | no trial data cached |
| Hospice care | 17 | 9.4 5.9–15.2ROR 9.5 · χ² 120 / p 4e-28 | 8.2 EB05 5.2 · IC025 +2.1 3/3 methods agree | Not in label — unassessed | serious PRR 3.5 | no trial data cached |
| Deep vein thrombosis (leg blood clot) | 106 | 8.9 7.4–10.7ROR 9.1 · χ² 733 / p 8e-162 | 8.7 EB05 7.3 · IC025 +2.8 3/3 methods agree | Labeled (related wording) related wording | serious PRR 6.2 | no trial data cached |
| Malnutrition | 16 | 7.9 4.8–12.8ROR 7.9 · χ² 89 / p 2e-21 | 6.7 EB05 4.3 · IC025 +1.9 3/3 methods agree | Not in label — unassessed | serious PRR 5.9 | no trial data cached |
| Metastases to bone | 23 | 7.7 5.1–11.5ROR 7.7 · χ² 127 / p 9e-30 | 6.8 EB05 4.7 · IC025 +2.0 3/3 methods agree | Not in label — unassessed | serious PRR 5.4 | no trial data cached |
| Meningioma | 20 | 7.4 4.8–11.5ROR 7.5 · χ² 105 / p 7e-25 | 6.5 EB05 4.4 · IC025 +1.9 3/3 methods agree | Not in label — unassessed | serious PRR 5.4 | no trial data cached |
| Metastases to lung | 15 | 7.1 4.3–11.8ROR 7.1 · χ² 73 / p 8e-18 | 6.0 EB05 3.8 · IC025 +1.7 3/3 methods agree | Not in label — unassessed | serious PRR 5.2 | no trial data cached |
| Mental status changes | 36 | 7.1 5.1–9.8ROR 7.1 · χ² 182 / p 1e-41 | 6.6 EB05 4.9 · IC025 +2.2 3/3 methods agree | Not in label — unassessed | serious PRR 5.7 | no trial data cached |
| Hyperbilirubinaemia | 13 | 6.9 4.0–11.9ROR 6.9 · χ² 60 / p 6e-15 | 5.7 EB05 3.5 · IC025 +1.6 3/3 methods agree | Not in label — unassessed | serious PRR 5.1 | no trial data cached |
| Supraventricular tachycardia | 12 | 6.9 3.9–12.1ROR 6.9 · χ² 54 / p 9e-14 | 5.6 EB05 3.4 · IC025 +1.5 3/3 methods agree | Not in label — unassessed | serious PRR 5.6 | no trial data cached |
| Oral candidiasis (oral thrush) | 16 | 6.7 4.1–11.0ROR 6.7 · χ² 72 / p 1e-17 | 5.7 EB05 3.7 · IC025 +1.7 3/3 methods agree | Not in label — unassessed | serious PRR 5.5 | no trial data cached |
| Breast cancer metastatic | 13 | 6.6 3.8–11.4ROR 6.6 · χ² 56 / p 3e-14 | 5.5 EB05 3.4 · IC025 +1.5 3/3 methods agree | Not in label — unassessed | serious PRR 4.9 | no trial data cached |
| Dehydration | 161 | 6.6 5.7–7.7ROR 6.8 · χ² 762 / p 4e-168 | 6.5 EB05 5.7 · IC025 +2.4 3/3 methods agree | Not in label — unassessed | serious PRR 5.2 | no trial data cached |
| Bacteraemia | 14 | 6.5 3.9–11.0ROR 6.5 · χ² 60 / p 6e-15 | 5.5 EB05 3.4 · IC025 +1.5 3/3 methods agree | Not in label — unassessed | serious PRR 4.7 | no trial data cached |
| Decreased appetite (loss of appetite) | 275 | 6.5 5.8–7.3ROR 6.9 · χ² 1,283 / p 2e-281 | 6.4 EB05 5.8 · IC025 +2.5 3/3 methods agree | Not in label — unassessed | serious PRR 5.5 | no trial data cached |
| Emphysema | 12 | 6.5 3.7–11.4ROR 6.5 · χ² 50 / p 7e-13 | 5.3 EB05 3.2 · IC025 +1.4 3/3 methods agree | Not in label — unassessed | serious PRR 4.9 | no trial data cached |
| Metastases to central nervous system | 15 | 6.4 3.9–10.6ROR 6.4 · χ² 63 / p 1e-15 | 5.4 EB05 3.5 · IC025 +1.6 3/3 methods agree | Not in label — unassessed | serious PRR 4.7 | no trial data cached |
| Osteonecrosis of jaw (jawbone death) | 29 | 6.4 4.4–9.1ROR 6.4 · χ² 126 / p 2e-29 | 5.8 EB05 4.2 · IC025 +1.9 3/3 methods agree | Not in label — unassessed | serious PRR 4.6 · ♀ 68% (drug 46%) | no trial data cached |
| Renal failure acute | 49 | 6.2 4.7–8.2ROR 6.3 · χ² 210 / p 8e-48 | 5.9 EB05 4.6 · IC025 +2.1 3/3 methods agree | Labeled (related wording) related wording | serious PRR 4.5 | no trial data cached |
| Cardiomegaly | 14 | 6.2 3.7–10.4ROR 6.2 · χ² 55 / p 5e-14 | 5.2 EB05 3.3 · IC025 +1.5 3/3 methods agree | Not in label — unassessed | serious PRR 4.6 | no trial data cached |
| Hypokalaemia (low potassium) | 51 | 6.1 4.6–8.0ROR 6.1 · χ² 211 / p 4e-48 | 5.8 EB05 4.6 · IC025 +2.1 3/3 methods agree | Not in label — unassessed | serious PRR 4.5 | no trial data cached |
| Pleural effusion | 67 | 6.0 4.7–7.6ROR 6.1 · χ² 275 / p 4e-62 | 5.8 EB05 4.7 · IC025 +2.1 3/3 methods agree | Not in label — unassessed | serious PRR 4.5 | no trial data cached |
| Anhedonia | 29 | 6.0 4.2–8.6ROR 6.0 · χ² 115 / p 3e-27 | 5.5 EB05 4.0 · IC025 +1.8 3/3 methods agree | Not in label — unassessed | serious PRR 4.5 | no trial data cached |
| Hypomagnesaemia | 15 | 5.9 3.6–9.8ROR 5.9 · χ² 56 / p 3e-14 | 5.1 EB05 3.3 · IC025 +1.5 3/3 methods agree | Not in label — unassessed | serious PRR 4.4 | no trial data cached |
| Pneumothorax | 17 | 5.9 3.6–9.4ROR 5.9 · χ² 64 / p 7e-16 | 5.1 EB05 3.4 · IC025 +1.5 3/3 methods agree | Not in label — unassessed | serious PRR 4.3 | no trial data cached |
| Anorexia | 14 | 5.9 3.5–9.9ROR 5.9 · χ² 52 / p 4e-13 | 5.0 EB05 3.2 · IC025 +1.4 3/3 methods agree | Likely indication confounding term in indications | serious PRR 5.6 | no trial data cached |
| Arteriosclerosis | 10 | 5.8 3.1–10.8ROR 5.8 · χ² 35 / p 2e-9 | 4.7 EB05 2.7 · IC025 +1.2 3/3 methods agree | Not in label — unassessed | serious PRR 4.3 | no trial data cached |
| Generalised oedema | 13 | 5.8 3.4–9.9ROR 5.8 · χ² 47 / p 4e-12 | 4.9 EB05 3.0 · IC025 +1.4 3/3 methods agree | Not in label — unassessed | serious PRR 4.3 | no trial data cached |
| Haematocrit decreased | 21 | 5.7 3.8–8.8ROR 5.8 · χ² 78 / p 6e-19 | 5.1 EB05 3.5 · IC025 +1.6 3/3 methods agree | Lab value / disease marker | serious PRR 4.5 | no trial data cached |
| Pulmonary embolism (lung blood clot) | 100 | 5.7 4.7–6.9ROR 5.8 · χ² 386 / p 3e-86 | 5.6 EB05 4.7 · IC025 +2.2 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 4.1 | no trial data cached |
| Electrolyte imbalance | 12 | 5.7 3.2–10.0ROR 5.7 · χ² 42 / p 5e-11 | 4.8 EB05 2.9 · IC025 +1.3 3/3 methods agree | Not in label — unassessed | serious PRR 4.3 | no trial data cached |
| Upper gastrointestinal haemorrhage | 17 | 5.5 3.4–8.8ROR 5.5 · χ² 58 / p 1e-14 | 4.8 EB05 3.2 · IC025 +1.5 3/3 methods agree | Not in label — unassessed | serious PRR 4.0 | no trial data cached |
| Ileus | 12 | 5.3 3.0–9.4ROR 5.3 · χ² 38 / p 4e-10 | 4.5 EB05 2.8 · IC025 +1.2 3/3 methods agree | Not in label — unassessed | serious PRR 3.9 | no trial data cached |
| Mitral valve incompetence | 11 | 5.3 2.9–9.6ROR 5.3 · χ² 34 / p 2e-9 | 4.4 EB05 2.7 · IC025 +1.1 3/3 methods agree | Not in label — unassessed | serious PRR 3.9 | no trial data cached |
| Unresponsive to stimuli | 25 | 5.3 3.6–7.8ROR 5.3 · χ² 83 / p 4e-20 | 4.9 EB05 3.5 · IC025 +1.6 3/3 methods agree | Not in label — unassessed | serious PRR 3.9 | no trial data cached |
| Metastases to liver | 17 | 5.3 3.3–8.5ROR 5.3 · χ² 55 / p 6e-14 | 4.7 EB05 3.1 · IC025 +1.4 3/3 methods agree | Not in label — unassessed | serious PRR 3.9 | 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 |
|---|---|---|---|---|---|---|
| Death | 406 | 2.6 2.3–2.8ROR 2.8 · χ² 406 / p 2e-90 | 2.6 EB05 2.4 · IC025 +1.2 3/3 methods agree | Outcome field, not a reaction | serious PRR 1.8 | no trial data cached |
| Diarrhoea (diarrhea) | 351 | 3.0 2.7–3.3ROR 3.2 · χ² 474 / p 2e-105 | 3.0 EB05 2.7 · IC025 +1.4 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 2.7 | no trial data cached |
| Decreased appetite (loss of appetite) | 275 | 6.5 5.8–7.3ROR 6.9 · χ² 1,283 / p 2e-281 | 6.4 EB05 5.8 · IC025 +2.5 3/3 methods agree | Not in label — unassessed | serious PRR 5.5 | no trial data cached |
| Asthenia (weakness) | 271 | 3.9 3.5–4.4ROR 4.2 · χ² 601 / p 6e-133 | 3.9 EB05 3.5 · IC025 +1.8 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 3.4 | no trial data cached |
| Pneumonia (lung infection) | 246 | 4.2 3.7–4.7ROR 4.4 · χ² 595 / p 9e-132 | 4.1 EB05 3.7 · IC025 +1.8 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 3.1 | no trial data cached |
| Weight decreased (weight loss) | 192 | 3.8 3.3–4.3ROR 3.9 · χ² 391 / p 3e-87 | 3.7 EB05 3.3 · IC025 +1.7 3/3 methods agree | Likely indication confounding term in indications; also in warnings | serious PRR 3.2 | no trial data cached |
| Anaemia (low red blood cells) | 167 | 4.8 4.1–5.5ROR 5.0 · χ² 499 / p 6e-111 | 4.7 EB05 4.1 · IC025 +2.0 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 3.7 | no trial data cached |
| Dehydration | 161 | 6.6 5.7–7.7ROR 6.8 · χ² 762 / p 4e-168 | 6.5 EB05 5.7 · IC025 +2.4 3/3 methods agree | Not in label — unassessed | serious PRR 5.2 | no trial data cached |
| Constipation | 135 | 3.4 2.9–4.0ROR 3.5 · χ² 229 / p 4e-52 | 3.4 EB05 2.9 · IC025 +1.5 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 3.5 | no trial data cached |
| Neutropenia (low neutrophils (infection-fighting cells)) | 110 | 4.4 3.7–5.3ROR 4.5 · χ² 291 / p 2e-65 | 4.4 EB05 3.7 · IC025 +1.8 3/3 methods agree | Not in label — unassessed | serious PRR 3.3 · 93% clinician | no trial data cached |
| Deep vein thrombosis (leg blood clot) | 106 | 8.9 7.4–10.7ROR 9.1 · χ² 733 / p 8e-162 | 8.7 EB05 7.3 · IC025 +2.8 3/3 methods agree | Labeled (related wording) related wording | serious PRR 6.2 | no trial data cached |
| Pulmonary embolism (lung blood clot) | 100 | 5.7 4.7–6.9ROR 5.8 · χ² 386 / p 3e-86 | 5.6 EB05 4.7 · IC025 +2.2 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 4.1 | no trial data cached |
| Malignant neoplasm progression | 97 | 5.2 4.3–6.3ROR 5.3 · χ² 326 / p 3e-73 | 5.1 EB05 4.3 · IC025 +2.0 3/3 methods agree | Reporting / coding artifact | serious PRR 3.8 | no trial data cached |
| Oedema peripheral (swelling of legs/feet) | 87 | 3.9 3.2–4.8ROR 4.0 · χ² 184 / p 3e-42 | 3.8 EB05 3.2 · IC025 +1.6 3/3 methods agree | Labeled (related wording) related wording | serious PRR 3.5 | no trial data cached |
| Disease progression | 81 | 3.8 3.0–4.7ROR 3.8 · χ² 161 / p 3e-37 | 3.7 EB05 3.1 · IC025 +1.5 3/3 methods agree | Reporting / coding artifact | serious PRR 2.8 | 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.
- Atelectasis — n=23, PRR 13.0
- End stage renal disease — n=33, PRR 9.8
- Metastases to bone — n=23, PRR 7.7
- Meningioma — n=20, PRR 7.4
- Mental status changes — n=36, PRR 7.1
- Dehydration — n=161, PRR 6.6
- Decreased appetite — n=275, PRR 6.5
- Osteonecrosis of jaw — n=29, PRR 6.4
- Hypokalaemia — n=51, PRR 6.1
- Pleural effusion — n=67, PRR 6.0
✓ A hand-written Bradford Hill causality assessment exists for this drug: Medroxyprogesterone acetate ↔ Meningioma.
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 Megestrol?
In FDA FAERS, the most frequently co-reported reaction terms for Megestrol are diarrhoea, decreased appetite, asthenia, pneumonia, weight decreased, anaemia. 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 Megestrol have an FDA boxed warning?
No. The FDA label retrieved for Megestrol has no boxed warning; see the label's Warnings and Precautions for the recognised risks.
Do FAERS signals prove that Megestrol 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 01119031-9943-4afb-8b45-cb71682f0482, effective 20260709; matched on
openfda.generic_name.exact:"MEGESTROL ACETATE") - 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, fieldpatient.drug.openfda.generic_name.exact, 272 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.