HIGH-VOLUME · FEMALE-LED
levothyroxine Side Effects
levothyroxine (also sold as Synthroid, Levoxyl) is HIGH-VOLUME in this FAERS book #13 of 524 by FAERS report count. Signature opener: FEMALE-LED - 81% of sex-coded reports are female (230,810 F / 54,811 M).
Data updated 2026-05-15
- 304,465
- FAERS reports
FAERS voluntary reports, 1997 to 2025. High volume tracks exposure and reporting culture; see methodology for de-dup rules.
levothyroxine reporting skew - 81% of sex-coded reports are female (230,810 F / 54,811 M). Volume band HIGH-VOLUME #13 of 524 by FAERS report count; caseload MEGA-CASE.
High-report extract for levothyroxine (Synthroid): 304,465 FAERS rows (1997-2025). Top named reactions: FATIGUE, NAUSEA, HEADACHE. Outcome stamps DEATH-HEAVY · HOSP-MID · FEMALE-LED. FAERS is voluntary signal detection, not incidence.
Counts from the openFDA FAERS extract (1997–2025). Stamps MEGA-CASE · DEATH-HEAVY · HOSP-MID · FEMALE-LED.
FATIGUE leads 25,847 of 304,465 reports
FEMALE-LED reporters · age peak 45-64
Female-led reporters (81% of sex-coded rows)
Age peak 45-64 (70,265 reports)
FAERS filings rising toward 2025
Reactions in Death Reports
Death-mentioned subset is HEAVY here (19,579 reports, 6.4%). Top co-reported reactions in that subset - voluntary, not causal.
| Reaction | Reports |
|---|---|
| DEATH | 7,288 |
| PNEUMONIA | 1,368 |
| DYSPNOEA | 1,316 |
| FATIGUE | 1,226 |
| ASTHENIA | 1,168 |
| DIARRHOEA | 1,092 |
| NAUSEA | 1,048 |
| VOMITING | 924 |
| PAIN | 903 |
| GENERAL PHYSICAL HEALTH DETERIORATION | 859 |
| FALL | 831 |
| DECREASED APPETITE | 802 |
| RENAL FAILURE | 793 |
| SEPSIS | 772 |
| RESPIRATORY FAILURE | 765 |
| CARDIAC ARREST | 754 |
| MALAISE | 736 |
| ANAEMIA | 719 |
| PYREXIA | 716 |
Reactions in Hospitalization Reports
Hospitalization mid-share (88,368, 29.0%). Co-reported reactions:
| Reaction | Reports |
|---|---|
| DYSPNOEA | 7,990 |
| NAUSEA | 7,480 |
| FATIGUE | 7,224 |
| FALL | 7,097 |
| DIARRHOEA | 6,600 |
| PNEUMONIA | 6,323 |
| ASTHENIA | 6,000 |
| PAIN | 5,982 |
| VOMITING | 5,854 |
| HEADACHE | 5,199 |
| DIZZINESS | 4,857 |
| PYREXIA | 4,621 |
| MALAISE | 4,354 |
| ARTHRALGIA | 3,838 |
| WEIGHT DECREASED | 3,804 |
| HYPERTENSION | 3,651 |
| HYPOTENSION | 3,587 |
| ANAEMIA | 3,554 |
How to read levothyroxine FAERS figures (MEGA-CASE · DEATH-HEAVY · HOSP-MID)
FAERS holds 304,465 voluntary reports linked to levothyroxine (Synthroid, Levoxyl, Tirosint), 1997-2025. Death is listed on 19,579 (6.4%). Hospitalization appears on 88,368 (29.0%). Top co-reported indication: Product Used For Unknown Indication.
MEGA-CASE books overweight common drugs and loud reporting cultures; FEMALE-LED is the page opener, not a per-patient risk.
Read with levothyroxine
Peers ranked by ABS(total_reports), then an ABS(death_share) pole; guide hop follows DEATH-HEAVY · HOSP-MID stamps.
ABS(total_reports) peer at 297,692 FAERS cases (Δ 6,773 lighter vs levothyroxine); DEATH-HEAVY · HOSP-HEAVY · SEX-BALANCED vs this page's MEGA-CASE · DEATH-HEAVY · HOSP-MID · FEMALE-LED.
ABS(total_reports) peer at 285,895 FAERS cases (Δ 18,570 lighter vs levothyroxine); DEATH-HEAVY · HOSP-HEAVY · SEX-BALANCED vs this page's MEGA-CASE · DEATH-HEAVY · HOSP-MID · FEMALE-LED.
ABS(total_reports) peer at 331,875 FAERS cases (Δ 27,410 heavier vs levothyroxine); DEATH-HEAVY · HOSP-HEAVY · SEX-BALANCED vs this page's MEGA-CASE · DEATH-HEAVY · HOSP-MID · FEMALE-LED.
ABS(total_reports) peer at 342,023 FAERS cases (Δ 37,558 heavier vs levothyroxine); DEATH-HEAVY · HOSP-HEAVY · SEX-BALANCED vs this page's MEGA-CASE · DEATH-HEAVY · HOSP-MID · FEMALE-LED.
ABS(death_share) pole at 62.1% death-mentioned reports (Δ 55.7 pp vs levothyroxine's DEATH-HEAVY): CASELOAD · HOSP-MID.
levothyroxine stamps DEATH-HEAVY · HOSP-MID; FAERS outcome shares are signal-detection rates, not incidence. Read them next to caseload MEGA-CASE and the label guide.