Losartan Potassium side effects: what 78,389 FDA adverse event reports show
Drug class
Angiotensin ii receptor blocker (arb)
Brand names
Losartan Potassium
Who reports
78,389 reports · 60% serious · 5,497 with death outcome · 60% female
Used for
Losartan potassium tablet is an angiotensin II receptor blocker (ARB) indicated for: • Treatment of hypertension, to lower blood pressure in adults and children greater than 6 years old. Lowering blood pressure reduces the risk of fatal and nonfatal cardiovascular events, primarily strokes and myocardial infarctions.
What it is
Losartan potassium is an angiotensin II receptor blocker acting on the At 1 receptor subtype. Losartan potassium, a non-peptide molecule, is chemically described as 2-butyl-4-chloro-1-[ p -( o -1 H- tetrazol-5-ylphenyl)benzyl]imidazole-5-methanol monopotassium salt.
Boxed warning
FETAL TOXICITY When pregnancy is detected, discontinue losartan potassium tablets as soon as possible. Drugs that act directly on the renin-angiotensin system can cause injury and death to the developing fetus. [see Warnings and Precautions (5.1) ]. WARNING: FETAL TOXICITY See full prescribing information for complete boxed warning.
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.
- 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.
- 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). 1,126 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 |
|---|---|---|---|---|---|---|
| Cardiospasm | 58 | 30.9 23.5–40.6ROR 30.9 · calibrated p 3e-4 ✓ | 27.5 EB05 22.1 · IC025 +4.1 3/3 methods agree | Likely indication confounding shares a disease stem with the indications wording | serious n=58 · ♀ 0% (drug 60%) | not reported in cached trials |
| Palmoplantar keratoderma | 59 | 23.8 18.2–31.0ROR 23.8 · calibrated p 0.001 ✓ | 21.8 EB05 17.5 · IC025 +3.8 3/3 methods agree | Not in label — unassessed | serious n=58 · ♀ 0% (drug 60%) | not reported in cached trials |
| Chronic kidney disease-mineral and bone disorder | 67 | 17.7 13.8–22.7ROR 17.7 · calibrated p 0.004 ✓ | 16.5 EB05 13.4 · IC025 +3.5 3/3 methods agree | Not in label — unassessed | serious n=67 | not reported in cached trials |
| Nephrogenic anaemia | 239 | 14.4 12.6–16.3ROR 14.4 · calibrated p 0.008 ✓ | 13.6 EB05 12.2 · IC025 +3.5 3/3 methods agree | Likely indication confounding shares a disease stem with the indications wording | serious n=239 | NCT00090259: 2/1,921 (0.1%) on Losartan Potassium (serious AE) |
| Hyperparathyroidism secondary | 126 | 13.9 11.7–16.7ROR 14.0 · calibrated p 0.010 ✓ | 13.2 EB05 11.4 · IC025 +3.4 3/3 methods agree | Not in label — unassessed | serious n=125 | not reported in cached trials |
| Eyelid pain | 80 | 11.5 9.2–14.3ROR 11.5 · calibrated p 0.021 ✓ | 10.8 EB05 8.9 · IC025 +3.0 3/3 methods agree | Not in label — unassessed | 100% consumer | not reported in cached trials |
| Atrial tachycardia | 83 | 10.9 8.8–13.6ROR 10.9 · calibrated p 0.025 ✓ | 10.3 EB05 8.5 · IC025 +3.0 3/3 methods agree | Not in label — unassessed | serious n=82 · ♀ 0% (drug 60%) | NCT00090259: 1/1,913 (0.1%) on Losartan Potassium (serious AE) |
| Essential hypertension | 89 | 9.5 7.7–11.7ROR 9.5 · calibrated p 0.041 ✓ | 9.0 EB05 7.5 · IC025 +2.8 3/3 methods agree | Labeled adverse reaction exact term | serious n=82 | not reported in cached trials |
| Pruritus genital | 80 | 9.5 7.6–11.8ROR 9.5 · calibrated p 0.041 ✓ | 8.9 EB05 7.3 · IC025 +2.8 3/3 methods agree | Not in label — unassessed | serious n=75 · ♀ 0% (drug 60%) | not reported in cached trials |
| Infusion site discharge | 51 | 8.2 6.2–10.8ROR 8.2 · calibrated p 0.067 | 7.6 EB05 5.9 · IC025 +2.4 3/3 methods agree | Not in label — unassessed | serious n=42 · ♀ 100% (drug 60%) · 100% consumer | not reported in cached trials |
| Rebound acid hypersecretion | 87 | 7.8 6.3–9.6ROR 7.8 · calibrated p 0.075 | 7.3 EB05 6.1 · IC025 +2.5 3/3 methods agree | Not in label — unassessed | serious n=87 | not reported in cached trials |
| Blood pressure inadequately controlled | 162 | 7.3 6.3–8.5ROR 7.3 · calibrated p 0.088 | 7.0 EB05 6.2 · IC025 +2.5 3/3 methods agree | Likely indication confounding shares a disease stem with the indications wording | serious n=114 | not reported in cached trials |
| Nephrogenic systemic fibrosis | 80 | 7.1 5.7–8.9ROR 7.2 · calibrated p 0.097 | 6.8 EB05 5.6 · IC025 +2.4 3/3 methods agree | Likely indication confounding shares a disease stem with the indications wording | serious n=80 · 100% clinician | not reported in cached trials |
| Carotid artery occlusion | 89 | 6.6 5.4–8.2ROR 6.6 · calibrated p 0.118 | 6.3 EB05 5.3 · IC025 +2.3 3/3 methods agree | Not in label — unassessed | serious n=89 · ♀ 34% (drug 60%) | not reported in cached trials |
| Ischaemic cardiomyopathy | 71 | 6.2 4.9–7.9ROR 6.3 · calibrated p 0.140 | 5.9 EB05 4.8 · IC025 +2.2 3/3 methods agree | Likely indication confounding shares a disease stem with the indications wording | serious n=71 · ♀ 0% (drug 60%) · 100% clinician | not reported in cached trials |
| End stage renal disease | 409 | 6.0 5.5–6.7ROR 6.1 · calibrated p 0.146 | 5.9 EB05 5.4 · IC025 +2.4 3/3 methods agree | Likely indication confounding term in indications | serious PRR 5.7 | not reported in cached trials |
| Angina unstable | 143 | 5.9 5.0–7.0ROR 5.9 · calibrated p 0.156 | 5.7 EB05 5.0 · IC025 +2.2 3/3 methods agree | Not in label — unassessed | serious n=143 · ♀ 26% (drug 60%) | not reported in cached trials |
| Skin hypertrophy | 60 | 5.8 4.5–7.5ROR 5.8 · calibrated p 0.168 | 5.5 EB05 4.4 · IC025 +2.0 3/3 methods agree | Labeled (related wording) related wording | serious n=55 | not reported in cached trials |
| Renal failure chronic | 166 | 5.8 5.0–6.8ROR 5.8 · calibrated p 0.166 | 5.6 EB05 4.9 · IC025 +2.2 3/3 methods agree | Likely indication confounding term in indications; also in warnings | serious PRR 5.4 | NCT00090259: 2/1,913 (0.1%) on Losartan Potassium (serious AE) |
| Bundle branch block left | 87 | 5.5 4.5–6.8ROR 5.5 · calibrated p 0.188 | 5.3 EB05 4.4 · IC025 +2.1 3/3 methods agree | Not in label — unassessed | serious n=86 · 100% clinician | not reported in cached trials |
| Orthopnoea | 65 | 5.5 4.3–7.1ROR 5.5 · calibrated p 0.190 | 5.2 EB05 4.3 · IC025 +2.0 3/3 methods agree | Not in label — unassessed | serious n=65 · 100% clinician | not reported in cached trials |
| Aortic stenosis | 69 | 5.4 4.2–6.8ROR 5.4 · calibrated p 0.203 | 5.1 EB05 4.2 · IC025 +2.0 3/3 methods agree | Not in label — unassessed | serious n=66 · 100% clinician | not reported in cached trials |
| Aortic arteriosclerosis | 51 | 5.4 4.1–7.1ROR 5.4 · calibrated p 0.206 | 5.1 EB05 4.0 · IC025 +1.9 3/3 methods agree | Not in label — unassessed | serious n=50 · 100% clinician | not reported in cached trials |
| Left ventricular hypertrophy | 82 | 5.2 4.2–6.5ROR 5.2 · calibrated p 0.219 | 5.0 EB05 4.1 · IC025 +2.0 3/3 methods agree | Likely indication confounding term in indications; also in warnings | serious n=80 | not reported in cached trials |
| Tension headache | 80 | 5.1 4.0–6.3ROR 5.1 · calibrated p 0.234 | 4.8 EB05 4.0 · IC025 +1.9 3/3 methods agree | Labeled (related wording) related wording | serious n=70 · ♀ 0% (drug 60%) | not reported in cached trials |
| Pre-existing condition improved | 117 | 5.0 4.2–6.0ROR 5.0 · calibrated p 0.234 | 4.9 EB05 4.2 · IC025 +2.0 3/3 methods agree | Not in label — unassessed | serious n=62 | not reported in cached trials |
| Infusion site haemorrhage | 60 | 5.0 3.9–6.5ROR 5.0 · calibrated p 0.239 | 4.8 EB05 3.8 · IC025 +1.8 3/3 methods agree | Not in label — unassessed | serious n=37 · ♀ 100% (drug 60%) · 100% consumer | NCT00090259: 1/1,921 (0.1%) on Losartan Potassium (serious AE) |
| Diverticulum intestinal | 80 | 5.0 4.0–6.2ROR 5.0 · calibrated p 0.242 | 4.8 EB05 4.0 · IC025 +1.9 3/3 methods agree | Not in label — unassessed | serious n=77 | NCT00090259: 1/1,921 (0.1%) on Losartan Potassium (serious AE) |
| Infusion site pruritus | 57 | 5.0 3.8–6.4ROR 5.0 · calibrated p 0.246 | 4.7 EB05 3.8 · IC025 +1.8 3/3 methods agree | Labeled (related wording) related wording | ♀ 100% (drug 60%) | not reported in cached trials |
| Seasonal allergy | 256 | 4.9 4.3–5.6ROR 4.9 · calibrated p 0.244 | 4.8 EB05 4.3 · IC025 +2.1 3/3 methods agree | Not in label — unassessed | serious n=144 · 76% consumer | not reported in cached trials |
| Haemorrhagic anaemia | 80 | 4.9 3.9–6.1ROR 4.9 · calibrated p 0.255 | 4.7 EB05 3.9 · IC025 +1.9 3/3 methods agree | Not in label — unassessed | serious n=80 | NCT00090259: 1/1,921 (0.1%) on Losartan Potassium (serious AE) |
| Suspected suicide | 85 | 4.8 3.9–6.0ROR 4.8 · calibrated p 0.258 | 4.6 EB05 3.9 · IC025 +1.9 3/3 methods agree | Not in label — unassessed | serious n=85 · 100% clinician | not reported in cached trials |
| Diabetic neuropathy | 88 | 4.8 3.9–5.9ROR 4.8 · calibrated p 0.263 | 4.6 EB05 3.9 · IC025 +1.9 3/3 methods agree | Likely indication confounding shares a disease stem with the indications wording | serious n=82 | not reported in cached trials |
| Hyperlipidaemia | 211 | 4.8 4.2–5.5ROR 4.8 · calibrated p 0.262 | 4.7 EB05 4.2 · IC025 +2.0 3/3 methods agree | Likely indication confounding term in indications | serious PRR 4.6 | not reported in cached trials |
| Product administration interrupted | 133 | 4.7 4.0–5.6ROR 4.7 · calibrated p 0.272 | 4.6 EB05 3.9 · IC025 +1.9 3/3 methods agree | Reporting / coding artifact | serious n=119 | not reported in cached trials |
| Tricuspid valve incompetence | 137 | 4.7 4.0–5.6ROR 4.7 · calibrated p 0.273 | 4.6 EB05 4.0 · IC025 +1.9 3/3 methods agree | Not in label — unassessed | serious PRR 4.4 | not reported in cached trials |
| Mitral valve incompetence | 196 | 4.7 4.1–5.4ROR 4.7 · calibrated p 0.272 | 4.6 EB05 4.1 · IC025 +2.0 3/3 methods agree | Not in label — unassessed | age-adj. PRR 4.0 · serious PRR 4.4 | not reported in cached trials |
| Loss of employment | 52 | 4.6 3.5–6.1ROR 4.6 · calibrated p 0.288 | 4.4 EB05 3.5 · IC025 +1.7 3/3 methods agree | Not in label — unassessed | serious n=52 · ♀ 100% (drug 60%) · 100% clinician | not reported in cached trials |
| Benign prostatic hyperplasia | 86 | 4.5 3.6–5.6ROR 4.5 · calibrated p 0.302 | 4.3 EB05 3.6 · IC025 +1.8 3/3 methods agree | Not in label — unassessed | serious n=81 · ♀ 0% (drug 60%) | NCT00090259: 11/1,921 (0.6%) on Losartan Potassium (serious AE) |
| Sleep apnoea syndrome | 311 | 4.4 3.9–4.9ROR 4.4 · calibrated p 0.310 | 4.3 EB05 3.9 · IC025 +1.9 3/3 methods agree | Not in label — unassessed | age-adj. PRR 4.4 · serious PRR 4.3 | NCT00090259: 4/1,921 (0.2%) on Losartan Potassium (serious AE) |
Clinical concept groups
MedDRA splits one clinical problem across several terms (e.g. "neutropenia", "neutrophil count decreased", "agranulocytosis"), which dilutes term-level signals. These rows count reports with any term in a concept group (an exact union, not a sum), compared with all other drugs. Groups are hand-built and listed in the methods.
| Concept | Reports | PRR 95% CI | Reading |
|---|---|---|---|
| Heart failure | 1,791 | 2.72.6–2.8 | signal |
| Hyponatraemia | 711 | 2.42.2–2.6 | signal |
| Kidney injury | 3,864 | 2.32.2–2.3 | signal |
| Arrhythmia / qt | 1,624 | 2.32.1–2.4 | signal |
| Myocardial infarction | 1,689 | 2.22.1–2.3 | signal |
| Hypoglycaemia | 760 | 2.12.0–2.3 | raised |
| Fall / fracture | 2,813 | 2.01.9–2.1 | raised |
| Hyperglycaemia / diabetes | 2,514 | 1.91.9–2.0 | raised |
| Anaemia | 2,142 | 1.91.8–2.0 | raised |
| Gi bleeding | 1,285 | 1.91.8–2.0 | raised |
| Serious infection | 4,808 | 1.71.6–1.7 | raised |
| Stroke | 1,552 | 1.71.6–1.8 | raised |
| Depression | 1,720 | 1.61.6–1.7 | raised |
| Rhabdomyolysis / myopathy | 482 | 1.61.5–1.7 | raised |
| Pancreatitis | 443 | 1.51.3–1.6 | raised |
| Tendon disorder | 202 | 1.41.2–1.6 | raised |
Trial evidence (ClinicalTrials.gov)
✓ Trial adverse-event data found on ClinicalTrials.gov
Largest completed trials with posted results that list Losartan Potassium 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 (8 of 40 signal terms matched).
- NCT00090259 — Study to Evaluate Potential Decrease in Hospitalization Events, Time Between Events, and Increasing Longevity (N=3834, PHASE3; 813 AE terms posted; arms: Losartan 50 mg; Losartan 150 mg)
- NCT00546052 — A 52 Week Study to Evaluate the Effects of Losartan With or Without HCTZ on Plasma Glucose, Metabolic Paramete (N=1738, PHASE3; 37 AE terms posted; arms: Overall ITT)
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 |
|---|---|---|---|---|---|---|
| Fatigue (tiredness) | 5,821 | 2.0 2.0–2.1ROR 2.1 · calibrated p 0.993 | 2.0 EB05 2.0 · IC025 +1.0 | Labeled adverse reaction exact term | age-adj. PRR 1.8 · serious PRR 2.0 | NCT00090259: 1/1,921 (0.1%) on Losartan Potassium (serious AE) |
| Diarrhoea (diarrhea) | 4,686 | 2.0 1.9–2.0ROR 2.0 · calibrated p 0.952 | 1.9 EB05 1.9 · IC025 +0.9 | Labeled adverse reaction exact term | age-adj. PRR 1.7 · serious PRR 1.9 | NCT00090259: 5/1,921 (0.3%) on Losartan Potassium (serious AE) |
| Nausea | 4,579 | 1.6 1.5–1.6ROR 1.6 · calibrated p 0.699 | 1.6 EB05 1.5 · IC025 +0.6 | Labeled adverse reaction exact term | age-adj. PRR 1.5 · serious PRR 1.7 | NCT00090259: 1/1,921 (0.1%) on Losartan Potassium (serious AE) |
| Drug ineffective (drug did not work) | 4,263 | 0.9 0.8–0.9ROR 0.9 · calibrated p 0.217 | 0.9 EB05 0.8 · IC025 -0.3 PRR-only: not supported by EBGM or IC | Reporting / coding artifact | age-adj. PRR 1.0 · serious PRR 1.0 | not reported in cached trials |
| Dyspnoea (shortness of breath) | 4,212 | 2.0 1.9–2.1ROR 2.1 · calibrated p 0.973 | 2.0 EB05 1.9 · IC025 +0.9 | Labeled adverse reaction exact term | age-adj. PRR 1.7 · serious PRR 1.9 | NCT00090259: 2/1,921 (0.1%) on Losartan Potassium (serious AE) |
| Dizziness | 3,880 | 2.1 2.0–2.2ROR 2.1 · calibrated p 0.978 | 2.1 EB05 2.0 · IC025 +1.0 3/3 methods agree | Labeled adverse reaction exact term | age-adj. PRR 1.8 · serious PRR 2.2 | NCT00090259: 7/1,921 (0.4%) on Losartan Potassium (serious AE) |
| Headache | 3,747 | 1.6 1.6–1.7ROR 1.6 · calibrated p 0.727 | 1.6 EB05 1.6 · IC025 +0.6 | Labeled adverse reaction exact term | age-adj. PRR 1.6 · serious PRR 1.8 | NCT00090259: 1/1,913 (0.1%) on Losartan Potassium (serious AE) |
| Pain | 3,456 | 1.5 1.5–1.6ROR 1.5 · calibrated p 0.659 | 1.5 EB05 1.5 · IC025 +0.5 | Labeled adverse reaction exact term | age-adj. PRR 1.7 · serious PRR 1.5 | NCT00090259: 2/1,921 (0.1%) on Losartan Potassium (serious AE) |
| Arthralgia (joint pain) | 2,819 | 1.8 1.8–1.9ROR 1.9 · calibrated p 0.862 | 1.8 EB05 1.8 · IC025 +0.8 | Labeled adverse reaction exact term | age-adj. PRR 1.7 · serious PRR 2.0 | NCT00090259: 3/1,921 (0.2%) on Losartan Potassium (serious AE) |
| Asthenia (weakness) | 2,780 | 2.0 1.9–2.1ROR 2.0 · calibrated p 0.954 | 2.0 EB05 1.9 · IC025 +0.9 | Labeled adverse reaction exact term | age-adj. PRR 1.6 · serious PRR 1.9 | NCT00090259: 1/1,921 (0.1%) on Losartan Potassium (serious AE) |
| Cough | 2,777 | 2.7 2.6–2.8ROR 2.7 · calibrated p 0.721 | 2.7 EB05 2.6 · IC025 +1.3 3/3 methods agree | Labeled adverse reaction exact term | age-adj. PRR 2.2 · serious PRR 2.6 | NCT00090259: 1/1,913 (0.1%) on Losartan Potassium (serious AE) |
| Fall | 2,613 | 2.1 2.0–2.2ROR 2.1 · calibrated p 0.978 | 2.1 EB05 2.0 · IC025 +1.0 3/3 methods agree | Not in label — unassessed | age-adj. PRR 1.6 · serious PRR 2.0 | NCT00090259: 12/1,921 (0.6%) on Losartan Potassium (serious AE) |
| Off label use (used outside approved label) | 2,609 | 0.8 0.8–0.8ROR 0.8 · calibrated p 0.182 | 0.8 EB05 0.8 · IC025 -0.4 PRR-only: not supported by EBGM or IC | Reporting / coding artifact | age-adj. PRR 0.8 · serious PRR 0.8 | not reported in cached trials |
| Pruritus (itching) | 2,517 | 1.8 1.7–1.9ROR 1.8 · calibrated p 0.836 | 1.8 EB05 1.7 · IC025 +0.8 | Labeled adverse reaction exact term | age-adj. PRR 1.6 · serious PRR 1.8 | not reported in cached trials |
| Rash | 2,472 | 1.5 1.5–1.6ROR 1.5 · calibrated p 0.670 | 1.5 EB05 1.5 · IC025 +0.5 | Labeled adverse reaction exact term | age-adj. PRR 1.5 · serious PRR 1.5 | 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.
- Palmoplantar keratoderma — n=59, PRR 23.8
- Chronic kidney disease-mineral and bone disorder — n=67, PRR 17.7
- Hyperparathyroidism secondary — n=126, PRR 13.9
- Eyelid pain — n=80, PRR 11.5
- Atrial tachycardia — n=83, PRR 10.9 (also seen in trial arm)
- Pruritus genital — n=80, PRR 9.5
- Infusion site discharge — n=51, PRR 8.2
- Rebound acid hypersecretion — n=87, PRR 7.8
- Carotid artery occlusion — n=89, PRR 6.6
- Angina unstable — n=143, PRR 5.9
✓ A hand-written Bradford Hill causality assessment exists for this drug: Losartan ↔ Renal failure.
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 Losartan Potassium?
In FDA FAERS, the most frequently co-reported reaction terms for Losartan Potassium are fatigue, diarrhoea, nausea, dyspnoea, dizziness, 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 Losartan Potassium have an FDA boxed warning?
Yes. The current FDA label carries a boxed warning: FETAL TOXICITY When pregnancy is detected, discontinue losartan potassium tablets as soon as possible. Drugs that act directly on the renin-angiotensin system can cause injury and death to the developing fetus. [see Warnings and Precautions (5.1) ]. WARNING: FETAL TOXICITY See full prescribing information for complete boxed warning.
Do FAERS signals prove that Losartan Potassium 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 9501dfaa-c8cf-46d6-8bec-936c4fd8fe03, effective 20260716; matched on
openfda.generic_name.exact:"LOSARTAN") - 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, 1,166 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
LOSARTAN, 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.