Liothyronine side effects: what 8,654 FDA adverse event reports show
Drug class
L-triiodothyronine (t3)
Label matched
Liothyronine Sodium (Liothyronine Sodium)
Who reports
8,654 reports · 45% serious · 205 with death outcome · 89% female
Used for
Liothyronine sodium is an L-triiodothyronine (T3) indicated for: Hypothyroidism: As replacement in primary (thyroidal), secondary (pituitary), and tertiary (hypothalamic) congenital or acquired hypothyroidism ( 1.1 ) Pituitary Thyrotropin (Thyroid-Stim.
What it is
Liothyronine Sodium Tablets, USP contain the active ingredient, liothyronine (L-triiodothyronine or LT3), a synthetic form of a thyroid hormone liothyronine in sodium salt form. It is chemically designated as L-Tyrosine, O -(4-hydroxy-3-iodophenyl)-3,5-diiodo-, monosodium salt.
Boxed warning
NOT FOR TREATMENT OF OBESITY OR FOR WEIGHT LOSS Thyroid hormones, including liothyronine sodium, either alone or with other therapeutic agents, should not be used for the treatment of obesity or for weight loss. In euthyroid patients, doses within the range of daily hormonal requirements are ineffective for weight reduction.
Causality screen of the 40 strongest signals
What the badges mean
- Labeled — boxed warning The term (or its clinical synonym) appears in the FDA boxed warning: causality is regulator-recognised and considered serious.
- 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. 1,018 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 |
|---|---|---|---|---|---|---|
| Ejection fraction | 211 | 1,377.3 1,164.2–1,629.4ROR 1,411.6 · χ² 183,200 / p <1e-300 | 809.3 EB05 721.7 · IC025 +7.9 3/3 methods agree | Not in label — unassessed | serious n=211 | no trial data cached |
| Sensitisation | 260 | 1,252.3 1,079.4–1,452.9ROR 1,291.0 · χ² 212,467 / p <1e-300 | 774.7 EB05 698.9 · IC025 +8.1 3/3 methods agree | Not in label — unassessed | serious n=260 | no trial data cached |
| Polycystic ovaries | 263 | 487.8 427.9–556.1ROR 503.1 · χ² 105,709 / p <1e-300 | 393.6 EB05 355.3 · IC025 +7.6 3/3 methods agree | Not in label — unassessed | serious n=262 | no trial data cached |
| Tri-iodothyronine abnormal | 14 | 324.7 185.9–567.3ROR 325.2 · χ² 3,698 / p <1e-300 | 206.0 EB05 130.4 · IC025 +3.8 3/3 methods agree | Not in label — unassessed | – | no trial data cached |
| Tri-iodothyronine increased | 37 | 247.6 176.6–347.1ROR 248.7 · χ² 8,012 / p <1e-300 | 201.2 EB05 152.5 · IC025 +5.3 3/3 methods agree | Not in label — unassessed | serious n=13 · 83% consumer | no trial data cached |
| Tri-iodothyronine decreased | 39 | 196.2 141.6–271.7ROR 197.0 · χ² 6,818 / p <1e-300 | 166.7 EB05 127.2 · IC025 +5.3 3/3 methods agree | Not in label — unassessed | serious n=10 · 86% consumer | no trial data cached |
| Ejection fraction abnormal | 83 | 175.5 140.6–219.1ROR 177.2 · χ² 13,252 / p <1e-300 | 157.7 EB05 131.2 · IC025 +6.0 3/3 methods agree | Lab value / disease marker | serious n=83 | no trial data cached |
| Rhinitis allergic | 264 | 153.1 135.4–173.1ROR 157.9 · χ² 37,350 / p <1e-300 | 142.5 EB05 128.6 · IC025 +6.6 3/3 methods agree | Not in label — unassessed | serious n=263 | no trial data cached |
| Nephrectomy | 85 | 147.3 118.4–183.1ROR 148.7 · χ² 11,494 / p <1e-300 | 134.6 EB05 112.3 · IC025 +5.9 3/3 methods agree | Not in label — unassessed | serious n=85 | no trial data cached |
| Thyroxine abnormal | 11 | 134.8 73.4–247.3ROR 134.9 · χ² 1,259 / p 5e-276 | 104.9 EB05 62.5 · IC025 +3.3 3/3 methods agree | Lab value / disease marker | – | no trial data cached |
| Obstructive sleep apnoea syndrome | 62 | 112.6 87.3–145.1ROR 113.4 · χ² 6,441 / p <1e-300 | 104.2 EB05 84.2 · IC025 +5.4 3/3 methods agree | Not in label — unassessed | serious n=61 | no trial data cached |
| Thyroxine decreased | 21 | 84.7 54.9–130.9ROR 84.9 · χ² 1,598 / p <1e-300 | 76.4 EB05 52.7 · IC025 +4.1 3/3 methods agree | Lab value / disease marker | serious n=5 | no trial data cached |
| Polycystic ovarian syndrome | 11 | 74.7 41.0–136.0ROR 74.8 · χ² 705 / p 1e-155 | 64.7 EB05 38.5 · IC025 +3.1 3/3 methods agree | Not in label — unassessed | serious n=11 | no trial data cached |
| Reaction to excipient | 52 | 55.9 42.5–73.6ROR 56.3 · χ² 2,688 / p <1e-300 | 53.7 EB05 42.5 · IC025 +4.7 3/3 methods agree | Not in label — unassessed | serious n=9 · 94% consumer | no trial data cached |
| Carpal tunnel syndrome | 285 | 50.2 44.7–56.3ROR 51.8 · χ² 13,411 / p <1e-300 | 49.0 EB05 44.4 · IC025 +5.3 3/3 methods agree | Not in label — unassessed | serious PRR 75.8 | no trial data cached |
| Blood test abnormal | 274 | 48.2 42.8–54.2ROR 49.7 · χ² 12,375 / p <1e-300 | 47.1 EB05 42.6 · IC025 +5.2 3/3 methods agree | Reporting / coding artifact | serious PRR 88.3 | no trial data cached |
| Blood thyroid stimulating hormone abnormal | 35 | 46.9 33.6–65.6ROR 47.1 · χ² 1,499 / p <1e-300 | 45.0 EB05 33.8 · IC025 +4.3 3/3 methods agree | Likely indication confounding term in indications; also in warnings | serious n=8 · 79% consumer | no trial data cached |
| Thyroxine free decreased | 10 | 44.4 23.8–83.0ROR 44.5 · χ² 375 / p 8e-84 | 40.5 EB05 23.5 · IC025 +2.8 3/3 methods agree | Lab value / disease marker | – | no trial data cached |
| Blood thyroid stimulating hormone decreased | 79 | 42.8 34.3–53.4ROR 43.2 · χ² 3,126 / p <1e-300 | 41.6 EB05 34.5 · IC025 +4.7 3/3 methods agree | Likely indication confounding term in indications; also in warnings | serious n=32 · 74% consumer | no trial data cached |
| Sleep apnoea syndrome | 315 | 40.5 36.3–45.2ROR 42.0 · χ² 11,918 / p <1e-300 | 39.8 EB05 36.2 · IC025 +5.0 3/3 methods agree | Not in label — unassessed | serious PRR 59.1 | no trial data cached |
| Sleep disorder due to a general medical condition | 254 | 38.6 34.2–43.7ROR 39.8 · χ² 9,134 / p <1e-300 | 37.9 EB05 34.2 · IC025 +4.9 3/3 methods agree | Not in label — unassessed | serious PRR 93.5 | no trial data cached |
| Reaction to drug excipients | 34 | 37.9 27.1–53.2ROR 38.1 · χ² 1,168 / p 3e-256 | 36.7 EB05 27.4 · IC025 +4.0 3/3 methods agree | Not in label — unassessed | 91% consumer | no trial data cached |
| Insulin-like growth factor increased | 22 | 37.8 24.8–57.5ROR 37.9 · χ² 739 / p 4e-163 | 36.1 EB05 25.1 · IC025 +3.7 3/3 methods agree | Lab value / disease marker | serious n=19 · ♀ 41% (drug 89%) | no trial data cached |
| Lichen sclerosus | 10 | 36.6 19.6–68.3ROR 36.6 · χ² 307 / p 6e-69 | 33.9 EB05 19.6 · IC025 +2.7 3/3 methods agree | Not in label — unassessed | serious n=10 | no trial data cached |
| Thyroid function test abnormal | 60 | 35.3 27.4–45.5ROR 35.5 · χ² 1,937 / p <1e-300 | 34.4 EB05 27.7 · IC025 +4.3 3/3 methods agree | Reporting / coding artifact | serious n=15 · 74% consumer | no trial data cached |
| Autoimmune thyroiditis | 52 | 33.9 25.8–44.6ROR 34.1 · χ² 1,606 / p <1e-300 | 33.1 EB05 26.2 · IC025 +4.2 3/3 methods agree | Likely indication confounding shares a disease stem with the indications wording | serious n=47 · 81% consumer | no trial data cached |
| Fibromyalgia | 329 | 33.2 29.9–37.0ROR 34.5 · χ² 10,129 / p <1e-300 | 32.7 EB05 29.9 · IC025 +4.8 3/3 methods agree | Not in label — unassessed | serious PRR 50.0 | no trial data cached |
| Hypothyroidism | 430 | 33.1 30.2–36.4ROR 34.8 · χ² 13,209 / p <1e-300 | 32.7 EB05 30.1 · IC025 +4.8 3/3 methods agree | Labeled — boxed warning exact term | serious PRR 39.3 | no trial data cached |
| Gluten sensitivity | 19 | 32.7 20.8–51.4ROR 32.8 · χ² 546 / p 6e-121 | 31.4 EB05 21.2 · IC025 +3.4 3/3 methods agree | Not in label — unassessed | serious n=6 | no trial data cached |
| Thyroid hormones decreased | 10 | 30.8 16.5–57.5ROR 30.9 · χ² 256 / p 6e-58 | 28.9 EB05 16.6 · IC025 +2.6 3/3 methods agree | Lab value / disease marker | serious n=6 | no trial data cached |
| Allergic reaction to excipient | 23 | 28.6 19.0–43.1ROR 28.6 · χ² 578 / p 5e-128 | 27.7 EB05 19.4 · IC025 +3.5 3/3 methods agree | Not in label — unassessed | serious n=7 · 87% consumer | no trial data cached |
| Pre-existing condition improved | 72 | 27.9 22.2–35.2ROR 28.2 · χ² 1,823 / p <1e-300 | 27.5 EB05 22.5 · IC025 +4.2 3/3 methods agree | Not in label — unassessed | serious n=33 | no trial data cached |
| Subcutaneous emphysema | 11 | 27.4 15.1–49.6ROR 27.4 · χ² 251 / p 7e-57 | 25.9 EB05 15.3 · IC025 +2.6 3/3 methods agree | Not in label — unassessed | serious n=11 | no trial data cached |
| Thyroidectomy | 16 | 22.8 13.9–37.3ROR 22.8 · χ² 309 / p 2e-69 | 22.0 EB05 14.2 · IC025 +2.9 3/3 methods agree | Likely indication confounding shares a disease stem with the indications wording | serious n=15 | no trial data cached |
| Immunoglobulins decreased | 12 | 21.4 12.2–37.8ROR 21.5 · χ² 212 / p 3e-48 | 20.4 EB05 12.0 · IC025 +2.6 3/3 methods agree | Lab value / disease marker | serious n=11 | no trial data cached |
| Blood thyroid stimulating hormone increased | 74 | 19.6 15.6–24.6ROR 19.7 · χ² 1,275 / p 2e-279 | 19.3 EB05 15.9 · IC025 +3.7 3/3 methods agree | Likely indication confounding term in indications; also in warnings | serious n=33 · 81% consumer | no trial data cached |
| Papillary thyroid cancer | 13 | 18.4 10.6–31.7ROR 18.4 · χ² 195 / p 1e-44 | 17.4 EB05 10.2 · IC025 +2.5 3/3 methods agree | Likely indication confounding shares a disease stem with the indications wording | serious n=13 | no trial data cached |
| Recalled product | 13 | 18.2 10.6–31.4ROR 18.3 · χ² 193 / p 3e-44 | 17.3 EB05 10.1 · IC025 +2.5 3/3 methods agree | Not in label — unassessed | serious n=13 | no trial data cached |
| Lyme disease | 24 | 17.6 11.8–26.3ROR 17.7 · χ² 357 / p 5e-80 | 17.2 EB05 12.0 · IC025 +3.0 3/3 methods agree | Not in label — unassessed | serious n=21 · 77% consumer | no trial data cached |
| Sleep disorder due to general medical condition, insomnia type | 46 | 17.4 13.0–23.3ROR 17.5 · χ² 691 / p 2e-152 | 17.2 EB05 13.3 · IC025 +3.4 3/3 methods agree | Not in label — unassessed | serious n=45 | no trial data cached |
Trial evidence (ClinicalTrials.gov)
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 |
|---|---|---|---|---|---|---|
| Drug ineffective (drug did not work) | 958 | 1.8 1.7–1.9ROR 1.9 · χ² 336 / p 2e-75 | 1.8 EB05 1.7 · IC025 +0.7 | Reporting / coding artifact | serious PRR 1.5 · 80% consumer | no trial data cached |
| Headache | 884 | 3.4 3.2–3.6ROR 3.7 · χ² 1,558 / p <1e-300 | 3.4 EB05 3.2 · IC025 +1.7 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 5.6 | no trial data cached |
| Fatigue (tiredness) | 846 | 2.6 2.5–2.8ROR 2.8 · χ² 892 / p 3e-196 | 2.6 EB05 2.5 · IC025 +1.3 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 2.9 · 71% consumer | no trial data cached |
| Nausea | 583 | 1.8 1.7–1.9ROR 1.8 · χ² 210 / p 6e-48 | 1.8 EB05 1.7 · IC025 +0.7 | Labeled adverse reaction exact term | serious PRR 2.4 | no trial data cached |
| Dyspnoea (shortness of breath) | 558 | 2.4 2.2–2.6ROR 2.5 · χ² 462 / p 8e-103 | 2.4 EB05 2.2 · IC025 +1.1 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 3.3 | no trial data cached |
| Pain | 480 | 1.9 1.7–2.1ROR 1.9 · χ² 206 / p 5e-47 | 1.9 EB05 1.8 · IC025 +0.8 | Labeled adverse reaction exact term | serious PRR 2.4 | no trial data cached |
| Hypertension (high blood pressure) | 467 | 5.3 4.9–5.8ROR 5.6 · χ² 1,658 / p <1e-300 | 5.3 EB05 4.9 · IC025 +2.3 3/3 methods agree | Likely indication confounding shares a disease stem with the indications wording | serious PRR 7.5 | no trial data cached |
| Malaise (feeling unwell) | 446 | 2.5 2.2–2.7ROR 2.5 · χ² 392 / p 1e-87 | 2.5 EB05 2.3 · IC025 +1.1 3/3 methods agree | Not in label — unassessed | serious PRR 2.1 · 80% consumer | no trial data cached |
| Weight increased (weight gain) | 441 | 4.8 4.4–5.3ROR 5.0 · χ² 1,335 / p 1e-292 | 4.8 EB05 4.4 · IC025 +2.1 3/3 methods agree | Labeled (related wording) related wording | serious PRR 5.6 | no trial data cached |
| Hypothyroidism | 430 | 33.1 30.2–36.4ROR 34.8 · χ² 13,209 / p <1e-300 | 32.7 EB05 30.1 · IC025 +4.8 3/3 methods agree | Labeled — boxed warning exact term | serious PRR 39.3 | no trial data cached |
| Feeling abnormal | 418 | 4.2 3.8–4.6ROR 4.4 · χ² 1,032 / p 1e-226 | 4.2 EB05 3.9 · IC025 +1.9 3/3 methods agree | Not in label — unassessed | serious PRR 4.3 · 78% consumer | no trial data cached |
| Dizziness | 397 | 1.9 1.8–2.1ROR 2.0 · χ² 182 / p 1e-41 | 1.9 EB05 1.8 · IC025 +0.8 | Not in label — unassessed | serious PRR 2.4 | no trial data cached |
| Diarrhoea (diarrhea) | 387 | 1.5 1.3–1.6ROR 1.5 · χ² 57 / p 2e-14 | 1.5 EB05 1.3 · IC025 +0.4 | Labeled adverse reaction exact term | serious PRR 1.7 | no trial data cached |
| Off label use (used outside approved label) | 370 | 1.0 0.9–1.1ROR 1.0 · χ² 0 / p 0.273 | 1.0 EB05 0.9 · IC025 -0.1 PRR-only: not supported by EBGM or IC | Reporting / coding artifact | serious PRR 1.1 | no trial data cached |
| Asthma | 358 | 7.8 7.0–8.6ROR 8.0 · χ² 2,105 / p <1e-300 | 7.7 EB05 7.0 · IC025 +2.8 3/3 methods agree | Not in label — unassessed | serious PRR 12.7 | 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.
- Ejection fraction — n=211, PRR 1,377.3
- Sensitisation — n=260, PRR 1,252.3
- Polycystic ovaries — n=263, PRR 487.8
- Tri-iodothyronine increased — n=37, PRR 247.6
- Tri-iodothyronine decreased — n=39, PRR 196.2
- Rhinitis allergic — n=264, PRR 153.1
- Nephrectomy — n=85, PRR 147.3
- Obstructive sleep apnoea syndrome — n=62, PRR 112.6
- Reaction to excipient — n=52, PRR 55.9
- Carpal tunnel syndrome — n=285, PRR 50.2
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 Liothyronine?
In FDA FAERS, the most frequently co-reported reaction terms for Liothyronine are headache, fatigue, nausea, dyspnoea, pain, hypertension. 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 Liothyronine have an FDA boxed warning?
Yes. The current FDA label carries a boxed warning: NOT FOR TREATMENT OF OBESITY OR FOR WEIGHT LOSS Thyroid hormones, including liothyronine sodium, either alone or with other therapeutic agents, should not be used for the treatment of obesity or for weight loss. In euthyroid patients, doses within the range of daily hormonal requirements are ineffective for weight reduction.
Do FAERS signals prove that Liothyronine 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 1133ebe8-38c2-2505-e063-6294a90aaa2f, effective 20240212; matched on
openfda.generic_name.exact:"LIOTHYRONINE SODIUM") - 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, 1,058 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.