Levothyroxine Sodium Anhydrous side effects: what 99,541 FDA adverse event reports show
Drug class
Not stated in label
Label matched
Levothyroxine Sodium Anhydrous (Levothyroxine Sodium)
Who reports
99,541 reports · 70% serious · 8,264 with death outcome · 76% female
Used for
Levothyroxine Sodium for Injection is indicated for the treatment of myxedema coma. Important Limitations of Use: The relative bioavailability between Levothyroxine Sodium for Injection and oral levothyroxine products has not been established. Caution should be used when switching patients from oral levothyroxine products to Levothyroxine Sodium for Injection as accurate dosing conversion has not been studied.
What it is
Levothyroxine Sodium for Injection contains synthetic crystalline levothyroxine (L-thyroxine) sodium salt. Levothyroxine sodium has an empirical formula of C 15 H 10 I 4 NNaO 4 , a molecular w.
Boxed warning
NOT FOR TREATMENT OF OBESITY OR FOR WEIGHT LOSS Thyroid hormones, including Levothyroxine Sodium for Injection, should not be used for the treatment of obesity or for weight loss. ( 5.3 ) Larger doses may produce serious or even life threatening manifestations of toxicity.
Causality screen of the 40 strongest signals
What the badges mean
- 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). 1,141 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 | 348 | 354.4 298.1–421.3ROR 355.7 · calibrated p 3e-12 ✓ | 130.3 EB05 119.2 · IC025 +6.6 3/3 methods agree | Not in label — unassessed | serious n=348 · ♀ 54% (drug 76%) | not reported in cached trials |
| Immunisation | 229 | 237.9 196.8–287.6ROR 238.5 · calibrated p 1e-10 ✓ | 110.2 EB05 98.7 · IC025 +6.3 3/3 methods agree | Not in label — unassessed | serious n=227 | not reported in cached trials |
| Palmoplantar keratoderma | 343 | 192.7 166.4–223.2ROR 193.4 · calibrated p 6e-10 ✓ | 99.7 EB05 91.1 · IC025 +6.3 3/3 methods agree | Not in label — unassessed | serious n=343 · ♀ 54% (drug 76%) | not reported in cached trials |
| Ejection fraction | 174 | 89.3 74.7–106.6ROR 89.4 · calibrated p 3e-7 ✓ | 62.2 EB05 54.9 · IC025 +5.5 3/3 methods agree | Not in label — unassessed | serious n=174 · ♀ 100% (drug 76%) | not reported in cached trials |
| Sensitisation | 221 | 85.4 73.0–99.9ROR 85.6 · calibrated p 4e-7 ✓ | 60.4 EB05 54.0 · IC025 +5.5 3/3 methods agree | Not in label — unassessed | serious n=220 · ♀ 100% (drug 76%) | not reported in cached trials |
| Total lung capacity abnormal | 99 | 73.9 58.7–92.9ROR 74.0 · calibrated p 1e-6 ✓ | 54.2 EB05 45.8 · IC025 +5.1 3/3 methods agree | Not in label — unassessed | serious n=99 · ♀ 0% (drug 76%) · 100% clinician | not reported in cached trials |
| C-reactive protein | 232 | 72.2 62.2–83.9ROR 72.4 · calibrated p 1e-6 ✓ | 53.6 EB05 48.0 · IC025 +5.4 3/3 methods agree | Lab value / disease marker | serious n=232 · ♀ 100% (drug 76%) · 100% clinician | not reported in cached trials |
| Neurologic neglect syndrome | 136 | 67.4 55.6–81.8ROR 67.5 · calibrated p 2e-6 ✓ | 50.7 EB05 44.0 · IC025 +5.1 3/3 methods agree | Not in label — unassessed | serious n=136 · ♀ 100% (drug 76%) · 100% clinician | not reported in cached trials |
| Pulmonary vasculitis | 122 | 63.1 51.5–77.2ROR 63.1 · calibrated p 4e-6 ✓ | 48.2 EB05 41.4 · IC025 +5.0 3/3 methods agree | Not in label — unassessed | serious n=122 · ♀ 0% (drug 76%) · 100% clinician | not reported in cached trials |
| Deep vein thrombosis postoperative | 399 | 53.7 48.1–59.9ROR 53.9 · calibrated p 9e-6 ✓ | 42.7 EB05 39.3 · IC025 +5.2 3/3 methods agree | Not in label — unassessed | serious n=399 · ♀ 100% (drug 76%) · 94% clinician | not reported in cached trials |
| Sedation complication | 479 | 49.8 45.1–55.0ROR 50.0 · calibrated p 1e-5 ✓ | 40.3 EB05 37.3 · IC025 +5.1 3/3 methods agree | Reporting / coding artifact | serious n=478 · ♀ 100% (drug 76%) | not reported in cached trials |
| Multiple drug therapy | 124 | 45.4 37.4–55.1ROR 45.4 · calibrated p 3e-5 ✓ | 37.2 EB05 32.0 · IC025 +4.7 3/3 methods agree | Reporting / coding artifact | serious n=124 · ♀ 100% (drug 76%) · 100% clinician | not reported in cached trials |
| Atrial tachycardia | 365 | 43.9 39.3–49.2ROR 44.1 · calibrated p 3e-5 ✓ | 36.4 EB05 33.3 · IC025 +4.9 3/3 methods agree | Not in label — unassessed | serious n=364 · ♀ 54% (drug 76%) | not reported in cached trials |
| Carotid artery thrombosis | 137 | 40.1 33.4–48.2ROR 40.2 · calibrated p 6e-5 ✓ | 33.6 EB05 29.2 · IC025 +4.6 3/3 methods agree | Not in label — unassessed | serious n=137 · ♀ 100% (drug 76%) · 100% clinician | not reported in cached trials |
| Mite allergy | 99 | 38.5 31.1–47.8ROR 38.6 · calibrated p 8e-5 ✓ | 32.5 EB05 27.4 · IC025 +4.5 3/3 methods agree | Not in label — unassessed | serious n=98 · ♀ 0% (drug 76%) · 100% clinician | not reported in cached trials |
| Spirometry abnormal | 89 | 37.5 29.9–47.0ROR 37.5 · calibrated p 9e-5 ✓ | 31.7 EB05 26.5 · IC025 +4.4 3/3 methods agree | Lab value / disease marker | serious n=89 · ♀ 0% (drug 76%) · 100% clinician | not reported in cached trials |
| Pruritus genital | 352 | 37.4 33.4–41.9ROR 37.5 · calibrated p 8e-5 ✓ | 31.8 EB05 29.1 · IC025 +4.8 3/3 methods agree | Not in label — unassessed | serious n=350 · ♀ 55% (drug 76%) | not reported in cached trials |
| Anti-cyclic citrullinated peptide antibody | 100 | 37.0 29.9–45.8ROR 37.0 · calibrated p 1e-4 ✓ | 31.4 EB05 26.5 · IC025 +4.4 3/3 methods agree | Lab value / disease marker | serious n=100 · ♀ 100% (drug 76%) · 100% clinician | not reported in cached trials |
| Lupus vulgaris | 169 | 34.7 29.5–40.9ROR 34.8 · calibrated p 1e-4 ✓ | 29.8 EB05 26.2 · IC025 +4.5 3/3 methods agree | Not in label — unassessed | serious n=169 · ♀ 100% (drug 76%) · 100% clinician | not reported in cached trials |
| Polycystic ovaries | 223 | 34.7 30.1–40.0ROR 34.8 · calibrated p 1e-4 ✓ | 29.8 EB05 26.7 · IC025 +4.6 3/3 methods agree | Not in label — unassessed | serious n=221 · ♀ 100% (drug 76%) | not reported in cached trials |
| Creatinine renal clearance decreased | 523 | 31.3 28.6–34.3ROR 31.5 · calibrated p 2e-4 ✓ | 27.3 EB05 25.4 · IC025 +4.6 3/3 methods agree | Lab value / disease marker | serious n=523 · ♀ 97% (drug 76%) | not reported in cached trials |
| Swollen joint count increased | 393 | 30.2 27.2–33.6ROR 30.4 · calibrated p 3e-4 ✓ | 26.5 EB05 24.4 · IC025 +4.5 3/3 methods agree | Lab value / disease marker | serious n=393 · ♀ 100% (drug 76%) · 100% clinician | not reported in cached trials |
| Catarrh | 105 | 28.1 22.9–34.4ROR 28.1 · calibrated p 4e-4 ✓ | 24.7 EB05 21.0 · IC025 +4.2 3/3 methods agree | Not in label — unassessed | serious n=104 · ♀ 0% (drug 76%) · 100% clinician | not reported in cached trials |
| Schizoaffective disorder | 210 | 27.8 24.1–32.1ROR 27.9 · calibrated p 4e-4 ✓ | 24.6 EB05 21.9 · IC025 +4.3 3/3 methods agree | Not in label — unassessed | serious n=210 · ♀ 100% (drug 76%) · 100% clinician | not reported in cached trials |
| Bronchopulmonary aspergillosis allergic | 104 | 26.8 21.9–32.9ROR 26.9 · calibrated p 5e-4 ✓ | 23.8 EB05 20.2 · IC025 +4.1 3/3 methods agree | Not in label — unassessed | serious n=104 | not reported in cached trials |
| Mycotic allergy | 95 | 26.6 21.5–33.0ROR 26.7 · calibrated p 6e-4 ✓ | 23.6 EB05 19.9 · IC025 +4.1 3/3 methods agree | Not in label — unassessed | serious n=95 · ♀ 0% (drug 76%) · 100% clinician | not reported in cached trials |
| Steroid dependence | 94 | 26.1 21.1–32.3ROR 26.1 · calibrated p 6e-4 ✓ | 23.2 EB05 19.5 · IC025 +4.0 3/3 methods agree | Not in label — unassessed | serious n=94 · ♀ 0% (drug 76%) · 100% clinician | not reported in cached trials |
| Antineutrophil cytoplasmic antibody positive | 80 | 25.9 20.5–32.7ROR 25.9 · calibrated p 7e-4 ✓ | 23.0 EB05 19.1 · IC025 +4.0 3/3 methods agree | Lab value / disease marker | serious n=80 · ♀ 0% (drug 76%) · 100% clinician | not reported in cached trials |
| X-ray abnormal | 191 | 25.1 21.6–29.2ROR 25.2 · calibrated p 7e-4 ✓ | 22.5 EB05 19.9 · IC025 +4.2 3/3 methods agree | Lab value / disease marker | serious n=191 · ♀ 100% (drug 76%) · 100% clinician | not reported in cached trials |
| Rheumatic fever | 450 | 24.1 21.9–26.6ROR 24.2 · calibrated p 8e-4 ✓ | 21.7 EB05 20.0 · IC025 +4.2 3/3 methods agree | Not in label — unassessed | serious n=450 · ♀ 100% (drug 76%) · 94% clinician | not reported in cached trials |
| Adjustment disorder | 133 | 23.8 19.9–28.5ROR 23.8 · calibrated p 9e-4 ✓ | 21.4 EB05 18.5 · IC025 +4.0 3/3 methods agree | Not in label — unassessed | serious n=132 · ♀ 100% (drug 76%) · 100% clinician | not reported in cached trials |
| Carotid artery occlusion | 369 | 23.5 21.1–26.2ROR 23.6 · calibrated p 9e-4 ✓ | 21.2 EB05 19.4 · IC025 +4.2 3/3 methods agree | Not in label — unassessed | serious n=369 | not reported in cached trials |
| Dust allergy | 96 | 23.2 18.8–28.6ROR 23.2 · calibrated p 0.001 ✓ | 20.9 EB05 17.6 · IC025 +3.9 3/3 methods agree | Not in label — unassessed | serious n=95 · ♀ 0% (drug 76%) · 100% clinician | not reported in cached trials |
| Systemic infection | 163 | 22.8 19.4–26.8ROR 22.8 · calibrated p 0.001 ✓ | 20.6 EB05 18.1 · IC025 +4.0 3/3 methods agree | Not in label — unassessed | serious n=163 · 100% clinician | not reported in cached trials |
| Adjustment disorder with depressed mood | 186 | 21.3 18.3–24.8ROR 21.4 · calibrated p 0.002 ✓ | 19.4 EB05 17.2 · IC025 +4.0 3/3 methods agree | Not in label — unassessed | serious n=186 · ♀ 100% (drug 76%) · 100% clinician | not reported in cached trials |
| Tension headache | 381 | 20.4 18.4–22.7ROR 20.5 · calibrated p 0.002 ✓ | 18.6 EB05 17.1 · IC025 +4.0 3/3 methods agree | Not in label — unassessed | serious n=370 | not reported in cached trials |
| Product monitoring error | 123 | 19.7 16.3–23.7ROR 19.7 · calibrated p 0.002 ✓ | 18.0 EB05 15.5 · IC025 +3.8 3/3 methods agree | Reporting / coding artifact | serious n=123 · 100% clinician | not reported in cached trials |
| Neuritis | 131 | 19.5 16.3–23.3ROR 19.5 · calibrated p 0.002 ✓ | 17.9 EB05 15.4 · IC025 +3.8 3/3 methods agree | Not in label — unassessed | serious n=131 · ♀ 0% (drug 76%) | not reported in cached trials |
| Sleep terror | 355 | 19.3 17.3–21.5ROR 19.4 · calibrated p 0.002 ✓ | 17.7 EB05 16.2 · IC025 +3.9 3/3 methods agree | Not in label — unassessed | serious n=349 | not reported in cached trials |
| Conjunctivitis allergic | 113 | 17.6 14.5–21.3ROR 17.6 · calibrated p 0.004 ✓ | 16.2 EB05 13.8 · IC025 +3.6 3/3 methods agree | Not in label — unassessed | serious n=113 · ♀ 0% (drug 76%) · 100% clinician | not reported in cached trials |
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 |
|---|---|---|---|
| Hyponatraemia | 1,439 | 3.83.6–4.0 | signal |
| Arrhythmia / qt | 2,765 | 3.02.9–3.1 | signal |
| Interstitial lung disease | 1,153 | 2.52.4–2.7 | signal |
| Fall / fracture | 4,367 | 2.42.4–2.5 | signal |
| Rhabdomyolysis / myopathy | 900 | 2.42.2–2.5 | signal |
| Anaemia | 3,239 | 2.32.2–2.4 | signal |
| Kidney injury | 4,355 | 2.02.0–2.1 | raised |
| Pancreatitis | 746 | 2.01.8–2.1 | raised |
| Liver injury | 2,767 | 1.91.9–2.0 | raised |
| Gi bleeding | 1,677 | 1.91.8–2.0 | raised |
| Hyperglycaemia / diabetes | 3,145 | 1.91.9–2.0 | raised |
| Heart failure | 1,615 | 1.91.8–2.0 | raised |
| Serious infection | 6,816 | 1.91.8–1.9 | raised |
| Hypoglycaemia | 835 | 1.81.7–2.0 | raised |
| Venous thromboembolism | 1,831 | 1.81.7–1.9 | raised |
| Depression | 2,373 | 1.81.7–1.9 | raised |
Trial evidence (ClinicalTrials.gov)
✓ Trial adverse-event data found on ClinicalTrials.gov
Largest completed trials with posted results that list Levothyroxine Sodium Anhydrous 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).
- NCT00388297 — Thyroid Therapy for Mild Thyroid Deficiency in Pregnancy (N=1203, PHASE3; 17 AE terms posted; arms: Levothyroxine for Subclinical Hypothyroi; Placebo for Levothyroxine - Subclinincal; Levothyroxine for Hypothyroxinemia - Hyp; Placebo for Levothyroxine)
- NCT04124705 — A Study of Armour® Thyroid Compared to Synthetic T4 (Levothyroxine) in Previously Hypothyroid Participants (N=284, PHASE2; 16 AE terms posted; arms: Armour® Thyroid; Levothyroxine)
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) | 8,159 | 2.2 2.2–2.3ROR 2.3 · calibrated p 0.887 | 2.2 EB05 2.2 · IC025 +1.1 3/3 methods agree | Not in label — unassessed | age-adj. PRR 2.0 · serious PRR 2.4 | NCT00388297: 5/259 (1.9%) on Levothyroxine Sodium Anhydrous; 4/336 (1.2%) control |
| Nausea | 7,152 | 1.9 1.9–2.0ROR 2.0 · calibrated p 0.937 | 1.9 EB05 1.9 · IC025 +0.9 | Not in label — unassessed | age-adj. PRR 1.8 · serious PRR 2.2 | NCT00388297: 15/259 (5.8%) on Levothyroxine Sodium Anhydrous; 8/336 (2.4%) control |
| Diarrhoea (diarrhea) | 6,473 | 2.1 2.1–2.2ROR 2.2 · calibrated p 0.947 | 2.1 EB05 2.1 · IC025 +1.0 3/3 methods agree | Labeled adverse reaction exact term | age-adj. PRR 1.9 · serious PRR 2.2 | not reported in cached trials |
| Headache | 6,277 | 2.1 2.1–2.2ROR 2.2 · calibrated p 0.953 | 2.1 EB05 2.1 · IC025 +1.0 3/3 methods agree | Not in label — unassessed | age-adj. PRR 2.1 · serious PRR 2.6 | NCT00388297: 4/259 (1.5%) on Levothyroxine Sodium Anhydrous; 8/336 (2.4%) control |
| Dyspnoea (shortness of breath) | 6,210 | 2.3 2.3–2.4ROR 2.4 · calibrated p 0.850 | 2.3 EB05 2.3 · IC025 +1.2 3/3 methods agree | Not in label — unassessed | age-adj. PRR 2.1 · serious PRR 2.3 | not reported in cached trials |
| Drug ineffective (drug did not work) | 5,307 | 0.8 0.8–0.9ROR 0.8 · calibrated p 0.206 | 0.8 EB05 0.8 · IC025 -0.3 PRR-only: not supported by EBGM or IC | Reporting / coding artifact | age-adj. PRR 1.0 · serious PRR 1.1 | not reported in cached trials |
| Pain | 5,233 | 1.8 1.8–1.8ROR 1.8 · calibrated p 0.854 | 1.8 EB05 1.8 · IC025 +0.8 | Not in label — unassessed | age-adj. PRR 2.1 · serious PRR 1.9 | NCT00388297: 1/339 (0.3%) on Levothyroxine Sodium Anhydrous (serious AE) |
| Dizziness | 4,995 | 2.1 2.1–2.2ROR 2.2 · calibrated p 0.960 | 2.1 EB05 2.1 · IC025 +1.0 3/3 methods agree | Not in label — unassessed | age-adj. PRR 1.9 · serious PRR 2.3 | not reported in cached trials |
| Vomiting | 4,485 | 2.0 2.0–2.1ROR 2.1 · calibrated p 0.983 | 2.0 EB05 2.0 · IC025 +1.0 | Not in label — unassessed | age-adj. PRR 2.0 · serious PRR 2.1 | NCT00388297: 15/259 (5.8%) on Levothyroxine Sodium Anhydrous; 8/336 (2.4%) control |
| Asthenia (weakness) | 4,293 | 2.4 2.3–2.5ROR 2.5 · calibrated p 0.820 | 2.4 EB05 2.3 · IC025 +1.2 3/3 methods agree | Not in label — unassessed | age-adj. PRR 2.0 · serious PRR 2.3 | not reported in cached trials |
| Fall | 4,079 | 2.6 2.5–2.7ROR 2.7 · calibrated p 0.743 | 2.6 EB05 2.5 · IC025 +1.3 3/3 methods agree | Not in label — unassessed | age-adj. PRR 2.0 · serious PRR 2.3 | not reported in cached trials |
| Malaise (feeling unwell) | 4,040 | 1.9 1.9–2.0ROR 2.0 · calibrated p 0.935 | 1.9 EB05 1.9 · IC025 +0.9 | Not in label — unassessed | age-adj. PRR 1.9 · serious PRR 2.2 | not reported in cached trials |
| Off label use (used outside approved label) | 4,025 | 1.0 0.9–1.0ROR 1.0 · calibrated p 0.290 | 1.0 EB05 1.0 · IC025 -0.1 PRR-only: not supported by EBGM or IC | Reporting / coding artifact | age-adj. PRR 1.0 · serious PRR 1.1 | not reported in cached trials |
| Arthralgia (joint pain) | 3,927 | 2.0 1.9–2.1ROR 2.0 · calibrated p 0.969 | 2.0 EB05 1.9 · IC025 +0.9 | Not in label — unassessed | age-adj. PRR 1.9 · serious PRR 2.3 | not reported in cached trials |
| Pruritus (itching) | 3,392 | 1.9 1.8–2.0ROR 1.9 · calibrated p 0.905 | 1.9 EB05 1.8 · IC025 +0.9 | Not in label — unassessed | age-adj. PRR 1.7 · serious PRR 2.2 | 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.
- Cardiospasm — n=348, PRR 354.4
- Immunisation — n=229, PRR 237.9
- Palmoplantar keratoderma — n=343, PRR 192.7
- Ejection fraction — n=174, PRR 89.3
- Sensitisation — n=221, PRR 85.4
- Total lung capacity abnormal — n=99, PRR 73.9
- Neurologic neglect syndrome — n=136, PRR 67.4
- Pulmonary vasculitis — n=122, PRR 63.1
- Deep vein thrombosis postoperative — n=399, PRR 53.7
- Atrial tachycardia — n=365, PRR 43.9
✓ A hand-written Bradford Hill causality assessment exists for this drug: Methotrexate Sodium ↔ Rheumatoid Arthritis.
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 Levothyroxine Sodium Anhydrous?
In FDA FAERS, the most frequently co-reported reaction terms for Levothyroxine Sodium Anhydrous are fatigue, nausea, diarrhoea, headache, dyspnoea, pain. 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 Levothyroxine Sodium Anhydrous 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 Levothyroxine Sodium for Injection, should not be used for the treatment of obesity or for weight loss. ( 5.3 ) Larger doses may produce serious or even life threatening manifestations of toxicity.
Do FAERS signals prove that Levothyroxine Sodium Anhydrous 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 ae9954a5-e196-449c-abea-ebe4afbee517, effective 20260812; matched on
openfda.generic_name.exact:"LEVOTHYROXINE SODIUM ANHYDROUS") - 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, 1,181 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
LEVOTHYROXINE, 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.