Minoxidil side effects: what 44,631 FDA adverse event reports show
Who reports
44,631 reports · 11% serious · 449 with death outcome · 42% female
Used for
Because of the potential for serious adverse effects, minoxidil tablets are indicated only in the treatment of hypertension that is symptomatic or associated with target organ damage and is not manageable with maximum therapeutic doses of a diuretic plus two other antihypertensive drugs.
What it is
DESCRIPTION Minoxidil tablets contain minoxidil, an antihypertensive peripheral vasodilator. Minoxidil occurs as a white to off-white, crystalline powder, soluble in alcohol and propylene glycol; sparingly soluble in methanol; slightly soluble in water; practically insoluble in chloroform, acetone and ethyl acetate.
Boxed warning
Minoxidil tablets contain the powerful antihypertensive agent, minoxidil, which may produce serious adverse effects. It can cause pericardial effusion, occasionally progressing to tamponade, and angina pectoris may be exacerbated.
Causality screen of the 40 strongest signals
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, for the 300 most-reported drugs, adjusted for age band), and flags pairs whose reports are unusually skewed by sex or come mostly from consumers. Each row also shows the PRR against the other drugs of the same FDA class, which removes most confounding by the condition being treated, and a calibrated p-value: on validation, known non-causes average an ROR of about 2, so significance is judged against that empirical null (✓ = p < 0.05 after calibration). 1,012 further terms are in the interactive explorer. Reaction links open the term's cross-drug page.
| Reaction | Reports | PRR 95% CI · ROR · χ²/p | EBGM EB05 · IC025 | Label screen | Serious-only & strata | Trial cross-check |
|---|---|---|---|---|---|---|
| Vascular anastomotic haemorrhage | 16 | 739.8 335.7–1,630.1ROR 740.0 · calibrated p 2e-12 ✓ | 212.9 EB05 139.0 · IC025 +4.0 3/3 methods agree vs other Arteriolar Vasodilators: PRR 2.0 (1.0–4.0) | Not in label — unassessed | serious n=16 | not reported in cached trials |
| Application site acne | 141 | 197.5 162.2–240.6ROR 198.2 · calibrated p 6e-10 ✓ | 136.2 EB05 118.3 · IC025 +6.3 3/3 methods agree vs other Arteriolar Vasodilators: PRR 2.7 (2.1–3.4) | Not in label — unassessed | 100% consumer | not reported in cached trials |
| Dandruff | 578 | 167.1 152.0–183.7ROR 169.3 · calibrated p 2e-9 ✓ | 122.5 EB05 114.4 · IC025 +6.7 3/3 methods agree vs other Arteriolar Vasodilators: PRR 2.3 (2.0–2.6) | Not in label — unassessed | serious n=9 · 99% consumer | not reported in cached trials |
| Application site dryness | 821 | 149.0 137.8–161.1ROR 151.7 · calibrated p 4e-9 ✓ | 112.6 EB05 106.3 · IC025 +6.6 3/3 methods agree vs other Arteriolar Vasodilators: PRR 2.2 (2.0–2.5) | Not in label — unassessed | ♀ 19% (drug 42%) · 100% consumer | not reported in cached trials |
| Hair injury | 65 | 131.2 99.7–172.8ROR 131.4 · calibrated p 2e-8 ✓ | 99.5 EB05 80.8 · IC025 +5.4 3/3 methods agree vs other Arteriolar Vasodilators: PRR 5.2 (3.3–8.2) | Not in label — unassessed | ♀ 80% (drug 42%) · 100% consumer | not reported in cached trials |
| Application site ulcer | 152 | 127.3 106.4–152.3ROR 127.7 · calibrated p 2e-8 ✓ | 98.8 EB05 86.3 · IC025 +6.0 3/3 methods agree vs other Arteriolar Vasodilators: PRR 2.3 (1.8–2.9) | Not in label — unassessed | serious n=5 · 98% consumer | not reported in cached trials |
| Application site alopecia | 11 | 115.6 59.7–223.8ROR 115.6 · calibrated p 6e-7 ✓ | 80.2 EB05 47.8 · IC025 +3.2 3/3 methods agree vs other Arteriolar Vasodilators: only this drug | Not in label — unassessed | – | not reported in cached trials |
| Hypertrichosis | 295 | 88.3 78.0–100.0ROR 88.9 · calibrated p 3e-7 ✓ | 73.9 EB05 67.1 · IC025 +5.9 3/3 methods agree vs other Arteriolar Vasodilators: PRR 2.1 (1.8–2.4) | Labeled adverse reaction exact term | serious n=107 · ♀ 70% (drug 42%) | not reported in cached trials |
| Perineal cyst | 11 | 87.7 46.0–167.0ROR 87.7 · calibrated p 3e-6 ✓ | 65.8 EB05 39.2 · IC025 +3.1 3/3 methods agree vs other Arteriolar Vasodilators: PRR 2.0 (0.9–4.6) | Not in label — unassessed | serious n=11 | not reported in cached trials |
| Vena cava injury | 14 | 87.5 49.4–154.9ROR 87.5 · calibrated p 2e-6 ✓ | 67.3 EB05 42.6 · IC025 +3.5 3/3 methods agree vs other Arteriolar Vasodilators: PRR 2.0 (1.0–4.2) | Not in label — unassessed | serious n=14 | not reported in cached trials |
| Application site papules | 159 | 83.3 70.4–98.7ROR 83.6 · calibrated p 5e-7 ✓ | 70.2 EB05 61.5 · IC025 +5.6 3/3 methods agree vs other Arteriolar Vasodilators: PRR 2.1 (1.7–2.6) | Not in label — unassessed | 100% consumer | not reported in cached trials |
| Application site exfoliation | 615 | 81.8 75.1–89.1ROR 83.0 · calibrated p 5e-7 ✓ | 69.5 EB05 65.0 · IC025 +5.9 3/3 methods agree vs other Arteriolar Vasodilators: PRR 2.2 (2.0–2.5) | Not in label — unassessed | ♀ 21% (drug 42%) · 99% consumer | not reported in cached trials |
| Application site pruritus | 2,926 | 69.5 66.9–72.1ROR 74.3 · calibrated p 1e-6 ✓ | 60.5 EB05 58.7 · IC025 +5.8 3/3 methods agree vs other Arteriolar Vasodilators: PRR 2.2 (2.1–2.4) | Not in label — unassessed | serious n=19 · 100% consumer | not reported in cached trials |
| Product formulation issue | 796 | 64.3 59.7–69.2ROR 65.4 · calibrated p 2e-6 ✓ | 56.5 EB05 53.3 · IC025 +5.7 3/3 methods agree vs other Arteriolar Vasodilators: PRR 12.7 (10.6–15.4) | Reporting / coding artifact | serious n=64 · ♀ 94% (drug 42%) · 92% consumer | not reported in cached trials |
| Application site irritation | 1,420 | 60.4 57.2–63.8ROR 62.4 · calibrated p 3e-6 ✓ | 53.5 EB05 51.2 · IC025 +5.6 3/3 methods agree vs other Arteriolar Vasodilators: PRR 2.3 (2.1–2.4) | Not in label — unassessed | serious n=5 · ♀ 19% (drug 42%) · 100% consumer | not reported in cached trials |
| Application site scab | 244 | 59.3 51.9–67.7ROR 59.6 · calibrated p 5e-6 ✓ | 52.5 EB05 47.2 · IC025 +5.4 3/3 methods agree vs other Arteriolar Vasodilators: PRR 2.3 (1.9–2.8) | Not in label — unassessed | serious n=5 · 99% consumer | not reported in cached trials |
| Hair texture abnormal | 1,409 | 54.7 51.8–57.8ROR 56.5 · calibrated p 6e-6 ✓ | 49.0 EB05 46.9 · IC025 +5.5 3/3 methods agree vs other Arteriolar Vasodilators: PRR 4.9 (4.4–5.4) | Not in label — unassessed | serious n=10 · ♀ 89% (drug 42%) · 99% consumer | not reported in cached trials |
| Adverse drug reaction | 8,585 | 49.8 48.8–50.8ROR 61.4 · calibrated p 4e-6 ✓ | 45.1 EB05 44.3 · IC025 +5.5 3/3 methods agree vs other Arteriolar Vasodilators: PRR 2.0 (1.9–2.0) | Reporting / coding artifact | serious PRR 0.7 · ♀ 0% (drug 42%) · 100% consumer | not reported in cached trials |
| Renal cyst haemorrhage | 21 | 49.5 31.6–77.7ROR 49.6 · calibrated p 3e-5 ✓ | 43.2 EB05 29.8 · IC025 +3.7 3/3 methods agree vs other Arteriolar Vasodilators: PRR 2.0 (1.1–3.7) | Not in label — unassessed | serious n=21 · ♀ 0% (drug 42%) | not reported in cached trials |
| Hair growth abnormal | 656 | 49.1 45.3–53.2ROR 49.8 · calibrated p 1e-5 ✓ | 44.4 EB05 41.6 · IC025 +5.3 3/3 methods agree vs other Arteriolar Vasodilators: PRR 5.4 (4.6–6.2) | Labeled (related wording) related wording | serious n=34 · ♀ 95% (drug 42%) · 97% consumer | not reported in cached trials |
| Trichorrhexis | 207 | 37.5 32.6–43.2ROR 37.7 · calibrated p 8e-5 ✓ | 34.7 EB05 30.9 · IC025 +4.8 3/3 methods agree vs other Arteriolar Vasodilators: PRR 3.2 (2.6–4.0) | Not in label — unassessed | ♀ 91% (drug 42%) · 99% consumer | not reported in cached trials |
| Application site paraesthesia | 93 | 35.8 29.0–44.2ROR 35.9 · calibrated p 1e-4 ✓ | 33.1 EB05 27.8 · IC025 +4.5 3/3 methods agree vs other Arteriolar Vasodilators: PRR 3.2 (2.3–4.4) | Not in label — unassessed | ♀ 72% (drug 42%) · 100% consumer | not reported in cached trials |
| Application site pain | 1,413 | 32.2 30.5–33.9ROR 33.2 · calibrated p 2e-4 ✓ | 30.1 EB05 28.8 · IC025 +4.8 3/3 methods agree vs other Arteriolar Vasodilators: PRR 2.4 (2.2–2.6) | Not in label — unassessed | serious n=13 · 99% consumer | not reported in cached trials |
| Hair colour changes | 712 | 28.1 26.1–30.3ROR 28.6 · calibrated p 3e-4 ✓ | 26.6 EB05 25.0 · IC025 +4.6 3/3 methods agree vs other Arteriolar Vasodilators: PRR 3.8 (3.4–4.4) | Not in label — unassessed | serious n=5 · ♀ 88% (drug 42%) · 99% consumer | not reported in cached trials |
| Application site inflammation | 72 | 26.0 20.5–32.9ROR 26.0 · calibrated p 7e-4 ✓ | 24.5 EB05 20.1 · IC025 +4.0 3/3 methods agree vs other Arteriolar Vasodilators: PRR 2.6 (1.8–3.6) | Not in label — unassessed | 96% consumer | not reported in cached trials |
| Central serous chorioretinopathy | 32 | 25.6 17.9–36.5ROR 25.6 · calibrated p 9e-4 ✓ | 24.0 EB05 17.8 · IC025 +3.6 3/3 methods agree vs other Arteriolar Vasodilators: PRR 2.0 (1.2–3.3) | Not in label — unassessed | serious n=32 · 100% clinician | not reported in cached trials |
| Application site hypersensitivity | 62 | 25.4 19.7–32.8ROR 25.4 · calibrated p 7e-4 ✓ | 24.0 EB05 19.4 · IC025 +3.9 3/3 methods agree vs other Arteriolar Vasodilators: PRR 4.8 (3.0–7.5) | Not in label — unassessed | 97% consumer | not reported in cached trials |
| Vascular compression | 15 | 23.8 14.1–39.9ROR 23.8 · calibrated p 0.002 ✓ | 22.0 EB05 14.0 · IC025 +2.9 3/3 methods agree vs other Arteriolar Vasodilators: PRR 2.0 (1.0–4.1) | Not in label — unassessed | serious n=15 | not reported in cached trials |
| Application site hypoaesthesia | 11 | 23.1 12.6–42.4ROR 23.1 · calibrated p 0.002 ✓ | 21.1 EB05 12.1 · IC025 +2.5 3/3 methods agree vs other Arteriolar Vasodilators: PRR 3.1 (1.2–8.1) | Not in label — unassessed | – | not reported in cached trials |
| Drug administered at inappropriate site | 500 | 23.0 21.0–25.1ROR 23.2 · calibrated p 1e-3 ✓ | 21.9 EB05 20.4 · IC025 +4.3 3/3 methods agree vs other Arteriolar Vasodilators: PRR 4.2 (3.6–4.9) | Not in label — unassessed | ♀ 86% (drug 42%) · 99% consumer | not reported in cached trials |
| Abdominal wall haemorrhage | 12 | 22.8 12.8–40.8ROR 22.8 · calibrated p 0.002 ✓ | 20.9 EB05 12.4 · IC025 +2.6 3/3 methods agree vs other Arteriolar Vasodilators: PRR 2.0 (0.9–4.5) | Not in label — unassessed | serious n=12 | not reported in cached trials |
| Seborrhoea | 165 | 22.0 18.8–25.7ROR 22.0 · calibrated p 0.001 ✓ | 21.0 EB05 18.4 · IC025 +4.1 3/3 methods agree vs other Arteriolar Vasodilators: PRR 5.4 (4.0–7.3) | Not in label — unassessed | ♀ 77% (drug 42%) · 98% consumer | not reported in cached trials |
| Application site pustules | 16 | 21.4 13.0–35.3ROR 21.4 · calibrated p 0.003 ✓ | 19.9 EB05 12.8 · IC025 +2.8 3/3 methods agree vs other Arteriolar Vasodilators: PRR 2.3 (1.1–4.7) | Not in label — unassessed | – | not reported in cached trials |
| Application site rash | 573 | 20.3 18.7–22.1ROR 20.6 · calibrated p 0.002 ✓ | 19.5 EB05 18.2 · IC025 +4.1 3/3 methods agree vs other Arteriolar Vasodilators: PRR 2.5 (2.2–2.9) | Not in label — unassessed | 99% consumer | not reported in cached trials |
| Application site discomfort | 73 | 19.8 15.6–25.0ROR 19.8 · calibrated p 0.002 ✓ | 18.9 EB05 15.5 · IC025 +3.7 3/3 methods agree vs other Arteriolar Vasodilators: PRR 2.3 (1.6–3.2) | Not in label — unassessed | 100% consumer | not reported in cached trials |
| Product administered at inappropriate site | 727 | 19.5 18.2–21.0ROR 19.9 · calibrated p 0.002 ✓ | 18.8 EB05 17.7 · IC025 +4.1 3/3 methods agree vs other Arteriolar Vasodilators: PRR 2.1 (1.9–2.4) | Reporting / coding artifact | serious n=11 · 99% consumer | not reported in cached trials |
| Application site infection | 20 | 19.0 12.2–29.8ROR 19.0 · calibrated p 0.004 ✓ | 17.9 EB05 12.0 · IC025 +2.9 3/3 methods agree vs other Arteriolar Vasodilators: PRR 2.5 (1.3–4.8) | Not in label — unassessed | serious n=6 · 85% consumer | not reported in cached trials |
| Hair disorder | 324 | 19.0 17.0–21.2ROR 19.1 · calibrated p 0.003 ✓ | 18.2 EB05 16.6 · IC025 +4.0 3/3 methods agree vs other Arteriolar Vasodilators: PRR 7.5 (5.9–9.6) | Labeled (related wording) related wording | ♀ 98% (drug 42%) · 100% consumer | not reported in cached trials |
| Blood 25-hydroxycholecalciferol decreased | 11 | 18.4 10.1–33.5ROR 18.4 · calibrated p 0.006 ✓ | 16.5 EB05 8.9 · IC025 +2.3 3/3 methods agree vs other Arteriolar Vasodilators: PRR 2.0 (0.9–4.6) | Lab value / disease marker | serious n=11 | not reported in cached trials |
| Mixed anxiety and depressive disorder | 13 | 17.7 10.2–30.8ROR 17.7 · calibrated p 0.006 ✓ | 16.2 EB05 9.3 · IC025 +2.5 3/3 methods agree vs other Arteriolar Vasodilators: PRR 2.0 (0.9–4.3) | Not in label — unassessed | serious n=13 | not reported in cached trials |
Trial evidence (ClinicalTrials.gov)
✓ Trial adverse-event data found on ClinicalTrials.gov
Largest completed trials with posted results that list Minoxidil as a study intervention. The right-hand column of the signal table shows whether each FAERS term was also recorded in these trials, with a real denominator (0 of 40 signal terms matched).
- NCT01226459 — Clinical Trial in Females for Female Pattern Hair Loss (N=404, PHASE3; 25 AE terms posted; arms: Vehicle Foam; Minoxidil Foam)
Caveats: trial populations, doses and follow-up differ from the reporting population; AE terms are sponsor-coded and matched here by wording; absence from a trial list means the term was not reported above the sponsor's frequency threshold, not that it cannot occur.
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 |
|---|---|---|---|---|---|---|
| Adverse drug reaction | 8,585 | 49.8 48.8–50.8ROR 61.4 · calibrated p 4e-6 ✓ | 45.1 EB05 44.3 · IC025 +5.5 3/3 methods agree vs other Arteriolar Vasodilators: PRR 2.0 (1.9–2.0) | Reporting / coding artifact | serious PRR 0.7 · ♀ 0% (drug 42%) · 100% consumer | not reported in cached trials |
| Drug ineffective (drug did not work) | 7,760 | 2.8 2.7–2.8ROR 3.2 · calibrated p 0.579 | 2.8 EB05 2.7 · IC025 +1.4 3/3 methods agree vs other Arteriolar Vasodilators: PRR 1.9 (1.8–1.9) | Reporting / coding artifact | serious PRR 1.1 · 97% consumer | not reported in cached trials |
| Alopecia (hair loss) | 3,801 | 9.2 9.0–9.5ROR 10.0 · calibrated p 0.032 ✓ | 9.1 EB05 8.8 · IC025 +3.1 3/3 methods agree vs other Arteriolar Vasodilators: PRR 2.4 (2.3–2.5) | Not in label — unassessed | serious PRR 4.2 · ♀ 89% (drug 42%) · 97% consumer | not reported in cached trials |
| Application site pruritus | 2,926 | 69.5 66.9–72.1ROR 74.3 · calibrated p 1e-6 ✓ | 60.5 EB05 58.7 · IC025 +5.8 3/3 methods agree vs other Arteriolar Vasodilators: PRR 2.2 (2.1–2.4) | Not in label — unassessed | serious n=19 · 100% consumer | not reported in cached trials |
| Off label use (used outside approved label) | 2,275 | 1.2 1.2–1.3ROR 1.2 · calibrated p 0.470 | 1.2 EB05 1.2 · IC025 +0.2 vs other Arteriolar Vasodilators: PRR 1.5 (1.4–1.6) | Reporting / coding artifact | serious PRR 1.1 · ♀ 89% (drug 42%) · 90% consumer | not reported in cached trials |
| Overdose | 1,461 | 3.2 3.0–3.3ROR 3.3 · calibrated p 0.549 | 3.2 EB05 3.0 · IC025 +1.6 3/3 methods agree vs other Arteriolar Vasodilators: PRR 8.2 (7.3–9.2) | Reporting / coding artifact | serious PRR 0.8 · ♀ 95% (drug 42%) · 97% consumer | not reported in cached trials |
| Application site irritation | 1,420 | 60.4 57.2–63.8ROR 62.4 · calibrated p 3e-6 ✓ | 53.5 EB05 51.2 · IC025 +5.6 3/3 methods agree vs other Arteriolar Vasodilators: PRR 2.3 (2.1–2.4) | Not in label — unassessed | serious n=5 · ♀ 19% (drug 42%) · 100% consumer | not reported in cached trials |
| Application site pain | 1,413 | 32.2 30.5–33.9ROR 33.2 · calibrated p 2e-4 ✓ | 30.1 EB05 28.8 · IC025 +4.8 3/3 methods agree vs other Arteriolar Vasodilators: PRR 2.4 (2.2–2.6) | Not in label — unassessed | serious n=13 · 99% consumer | not reported in cached trials |
| Hair texture abnormal | 1,409 | 54.7 51.8–57.8ROR 56.5 · calibrated p 6e-6 ✓ | 49.0 EB05 46.9 · IC025 +5.5 3/3 methods agree vs other Arteriolar Vasodilators: PRR 4.9 (4.4–5.4) | Not in label — unassessed | serious n=10 · ♀ 89% (drug 42%) · 99% consumer | not reported in cached trials |
| Headache | 1,342 | 1.0 1.0–1.1ROR 1.0 · calibrated p 0.311 | 1.0 EB05 1.0 · IC025 -0.1 PRR-only: not supported by EBGM or IC vs other Arteriolar Vasodilators: PRR 0.8 (0.8–0.9) | Not in label — unassessed | serious PRR 1.9 · 89% consumer | NCT01226459: 6/203 (3.0%) on Minoxidil |
| Incorrect dose administered | 1,325 | 2.8 2.6–2.9ROR 2.8 · calibrated p 0.684 | 2.8 EB05 2.6 · IC025 +1.4 3/3 methods agree vs other Arteriolar Vasodilators: PRR 3.2 (3.0–3.5) | Reporting / coding artifact | serious PRR 1.9 · ♀ 83% (drug 42%) · 97% consumer | not reported in cached trials |
| Inappropriate schedule of product administration | 1,200 | 3.2 3.0–3.4ROR 3.3 · calibrated p 0.547 | 3.2 EB05 3.0 · IC025 +1.6 3/3 methods agree vs other Arteriolar Vasodilators: PRR 2.0 (1.9–2.2) | Reporting / coding artifact | serious PRR 1.2 · ♀ 63% (drug 42%) · 98% consumer | not reported in cached trials |
| Product use in unapproved indication | 1,190 | 2.3 2.2–2.4ROR 2.3 · calibrated p 0.889 | 2.3 EB05 2.2 · IC025 +1.1 3/3 methods agree vs other Arteriolar Vasodilators: PRR 3.3 (3.0–3.6) | Reporting / coding artifact | serious PRR 2.1 · ♀ 91% (drug 42%) · 92% consumer | not reported in cached trials |
| Wrong technique in product usage process | 1,178 | 2.7 2.6–2.9ROR 2.8 · calibrated p 0.696 | 2.7 EB05 2.6 · IC025 +1.4 3/3 methods agree vs other Arteriolar Vasodilators: PRR 3.3 (3.0–3.6) | Reporting / coding artifact | serious PRR 2.0 · ♀ 87% (drug 42%) · 97% consumer | not reported in cached trials |
| Pruritus (itching) | 1,014 | 1.3 1.2–1.3ROR 1.3 · calibrated p 0.485 | 1.3 EB05 1.2 · IC025 +0.2 vs other Arteriolar Vasodilators: PRR 1.2 (1.1–1.2) | Not in label — unassessed | serious PRR 1.7 · ♀ 74% (drug 42%) · 89% consumer | not reported in cached trials |
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.
- Application site acne — n=141, PRR 197.5
- Dandruff — n=578, PRR 167.1
- Application site dryness — n=821, PRR 149.0
- Hair injury — n=65, PRR 131.2
- Application site ulcer — n=152, PRR 127.3
- Application site papules — n=159, PRR 83.3
- Application site exfoliation — n=615, PRR 81.8
- Application site pruritus — n=2,926, PRR 69.5
- Application site irritation — n=1,420, PRR 60.4
- Application site scab — n=244, PRR 59.3
✓ A hand-written Bradford Hill causality assessment exists for this drug: Minoxidil (oral) ↔ Pericardial effusion.
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 Minoxidil?
In FDA FAERS, the most frequently co-reported reaction terms for Minoxidil are alopecia, application site pruritus, application site irritation, application site pain, hair texture abnormal, headache. 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 Minoxidil have an FDA boxed warning?
Yes. The current FDA label carries a boxed warning: Minoxidil tablets contain the powerful antihypertensive agent, minoxidil, which may produce serious adverse effects. It can cause pericardial effusion, occasionally progressing to tamponade, and angina pectoris may be exacerbated.
Do FAERS signals prove that Minoxidil 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 0354a7f5-5917-44dc-9963-411104008cb5, effective 20260209; matched on
openfda.generic_name.exact:"MINOXIDIL") - 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, 1,052 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 - ClinicalTrials.gov API v2 (query
MINOXIDIL, results-bearing studies sorted by enrollment)
Page generated 2026-10-14. 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.