What the label lists and what reports show
Thalidomide side effects
Thalidomide's FDA label: “The most common adverse reactions (≥ 20%) are fatigue, hypocalcemia, edema, constipation, neuropathy-sensory, dyspnea, muscle weakness, leukopenia, neutropenia, rash/desquamation, confusion, anorexia, nausea, anxiety/agitation, asthenia, tremor, fever, weight …” FAERS holds 36,498 reports naming it through July 30, 2026; the reaction reported most often, leaving out the conditions it is used for, product-use terms and outcomes, is plasma cell myeloma (2,030 reports).
- No generic listed
- Boxed warning
Check it at the source: the thalidomide FDA label on DailyMed (effective March 24, 2023, Celgene Corporation); the FDA FAERS public dashboard.
What does the patient leaflet say about side effects?
From the patient leaflet: What are the possible side effects of THALOMID?THALOMID can cause serious side effects, including: • See "What is the most important information I should know about THALOMID?" • Drowsiness and sleepiness. See "What should I avoid while taking THALOMID?" • Nerve damage. Nerve damage is common with THALOMID. If the nerve damage is severe, it may not go away. Stop taking THALOMID and call your healthcare provider right away if you have any of these early symptoms of nerve damage in your hands, legs, or feet: o numbness o tingling o pain o burning sensation • Dizziness and decreased blood pressure when changing positions. THALOMID may cause a decrease in your blood pressure, and you may feel dizzy when you go from a lying down or sitting position to standing up. When changing positions, sit upright for a few minutes before standing to help prevent this. • Decreased white blood cell count. […]
Source: FDA drug label, NDA020785 (Bristol-Myers), as published by Celgene Corporation, effective March 24, 2023 (SPL set 2eda833b-1357-4ed4-a093-194524fcb061), via openFDA; the full label on DailyMed
What does the label list?
From the label: adverse reactionsThe most common adverse reactions (≥ 20%) are fatigue, hypocalcemia, edema, constipation, neuropathy-sensory, dyspnea, muscle weakness, leukopenia, neutropenia, rash/desquamation, confusion, anorexia, nausea, anxiety/agitation, asthenia, tremor, fever, weight loss, thrombosis/embolism, neuropathy-motor, weight gain, dizziness, and dry skin.
Table 1: Adverse Reactions Reported in ≥10% of Patients in the THALOMID/Dexamethasone Arm (Study 1 - Safety Population; N=204)
| Reaction | All Grades n (%) | Grade 3/4 n (%) | All Grades n (%) | Grade 3/4 n (%) |
|---|---|---|---|---|
| Metabolic/Laboratory | 97 (95) | 33 (32) | 96 (94) | 30 (29) |
| Hypocalcemia | 73 (72) | 11 (11) | 60 (59) | 5 (5) |
| Neurology | 92 (90) | 30 (29) | 76 (74) | 18 (18) |
| Neuropathy-sensory | 55 (54) | 4 (4) | 28 (28) | 1 (1) |
| Confusion | 29 (28) | 9 (9) | 12 (12) | 3 (3) |
| Anxiety/agitation | 26 (26) | 1 (1) | 14 (14) | 3 (3) |
| Tremor | 26 (26) | 1 (1) | 6 (6) | 0 (0) |
| Neuropathy-motor | 22 (22) | 8 (8) | 16 (16) | 5 (5) |
| Dizziness/ lightheadedness | 20 (20) | 1 (1) | 14 (14) | 0 (0) |
| Depressed level of consciousness | 16 (16) | 3 (3) | 3 (3) | 3 (3) |
| Constitutional Symptoms | 91 (89) | 19 (19) | 84 (82) | 16 (16) |
| Fatigue | 81 (79) | 17 (17) | 72 (71) | 13 (13) |
| Fever | 24 (24) | 1 (1) | 20 (20) | 3 (3) |
| Weight loss | 23 (23) | 1 (1) | 21 (21) | 2 (2) |
| Weight gain | 22 (22) | 1 (1) | 13 (13) | 0 (0) |
| Blood/Bone Marrow | 88 (86) | 29 (29) | 96 (94) | 19 (19) |
| Leukocytes (decreased) | 36 (35) | 6 (6) | 30 (29) | 3 (3) |
| Neutrophils (decreased) | 32 (31) | 10 (10) | 24 (24) | 10 (10) |
| Gastrointestinal | 83 (81) | 22 (22) | 70 (69) | 8 (8) |
| Constipation | 56 (55) | 8 (8) | 29 (28) | 1 (1) |
| Anorexia | 29 (28) | 4 (4) | 25 (24) | 2 (2) |
| Nausea | 29 (28) | 5 (5) | 23 (22) | 1 (1) |
| Mouth dryness | 12 (12) | 1 (1) | 6 (6) | 0 (0) |
| Cardiovascular | 70 (69) | 37 (36) | 60 (59) | 21 (21) |
| Edema | 58 (56) | 6 (6) | 47 (46) | 4 (4) |
Rows and numbers as the label prints them, under its own column headings (the first rows of a longer table where it runs on). A reaction in a trial table is not necessarily caused by the medicine, and trials differ from everyday use.
From the label: adverse reactions, continuedThe following clinically significant adverse reactions are described in detail in other labeling sections: • Teratogenicity [see Boxed Warning, Warnings and Precautions (5.1 , 5.2), and Patient Counseling Information (17) ] • Venous and Arterial Thromboembolism [see Boxed Warning, Warnings and Precautions (5.3), and Patient Counseling Information (17) ] • Increased Mortality in Patients with MM When Pembrolizumab Is Added to a Thalidomide Analogue and Dexamethasone [see Warnings and Precautions (5.4) ] • Drowsiness and Somnolence [see Warnings and Precautions (5.5) ] • Peripheral Neuropathy [see Warnings and Precautions (5.6) ] • Dizziness and Orthostatic Hypotension [see Warnings and Precautions (5.7) ] • Neutropenia [see Warnings and Precautions (5.8) ] • Thrombocytopenia [see Warnings and Precautions (5.9) ] • Increased HIV Viral Load [see Warnings and Precautions (5.10) ] • Bradycardia [see Warnings and Precautions (5.11) ] • Severe Cutaneous Reactions [see Warnings and Precautions (5.12) ] • Seizures [see Warnings and Precautions (5.13) ] • Tumor Lysis Syndrome [see Warnings and Precautions (5.14) ] • Hypersensitivity [see Warnings and Precautions (5.16) ] • MM: The most common adverse reactions (≥ 20%) are fatigue, hypocalcemia, edema, constipation, neuropathy-sensory, dyspnea, muscle weakness, leukopenia, neutropenia, rash/desquamation, confusion, anorexia, nausea …
Source: FDA drug label, NDA020785 (Bristol-Myers), as published by Celgene Corporation, effective March 24, 2023 (SPL set 2eda833b-1357-4ed4-a093-194524fcb061), via openFDA; the full label on DailyMed
What do FAERS reports show?
36,498 reports list thalidomide among the medicines taken, each a report of something that happened, not proof the medicine caused it; 12,161 are coded as a death and 10,617 as a hospital stay. Counts follow how widely a medicine is used and watched, and they are not a measure of how risky it is. Of the 20 reactions below, 16 are named by the same term (in US spelling) in the label's adverse reactions, warnings or patient leaflet; a reaction the label does not name may still be there under another word, and a report does not show that the medicine caused it.
Reports received each year
The 25 most reported reactions
Source: FDA Adverse Event Reporting System (FAERS) via openFDA, reports through July 30, 2026; reactions as MedDRA preferred terms
What next?
- Thalidomide: the full record
- label, generics, price, shortages, recalls
- Report a side effect to the FDA
- MedWatch
- Side effects hub
- the most reported medicines and reactions