What the label lists and what reports show
Glutamine side effects
Glutamine's FDA label: “Most common adverse reactions (incidence > 10%) are constipation, nausea, headache, abdominal pain, cough, pain in extremity, back pain, and chest pain.” FAERS holds 4,739 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 sickle cell anaemia with crisis (1,646 reports).
- Generic listed
Check it at the source: the glutamine FDA label on DailyMed (effective June 20, 2025); the FDA FAERS public dashboard.
What does the label list?
From the label: adverse reactionsMost common adverse reactions (incidence > 10%) are constipation, nausea, headache, abdominal pain, cough, pain in extremity, back pain, and chest pain.
Table 2. Adverse Reactions Occurring at an Incidence > 10% in Clinical Studies of Endari
| Adverse reaction | Endari N = 187 (%) | Placebo N = 111 (%) |
|---|---|---|
| Constipation | 21 | 18 |
| Nausea | 19 | 14 |
| Headache | 18 | 15 |
| Abdominal Pain Abdominal pain = abdominal pain and abdominal pain, upper | 17 | 16 |
| Cough | 16 | 14 |
| Pain in extremity | 13 | 7 |
| Back pain | 12 | 5 |
| Chest pain | 12 | 8 |
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, continuedMost common adverse reactions (incidence > 10%) are constipation, nausea, headache, abdominal pain, cough, pain in extremity, back pain, and chest pain. ( 6 ) To report SUSPECTED ADVERSE REACTIONS, contact Emmaus Medical, Inc. at 1-877-420-6493 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch 6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. The data described below reflect exposure to Endari in 187 patients, including 136 exposed for 6 months and 109 exposed for ≥1 year. Endari was studied in 2 placebo-controlled clinical trials (a phase 3 study, n=230 and a phase 2 study, n=70). In these trials, patients with sickle cell anemia or sickle β 0 -thalassemia were randomized to receive Endari (n=187) or placebo (n=111) orally twice daily for 48 weeks followed by 3 weeks of tapering. Both studies included pediatric and adult patients (5-58 years of age) and 54% were female. The majority of patients were black (97.3%), had a diagnosis of sickle cell anemia (89.9%) and were receiving hydroxyurea at baseline (63.4%). Treatment discontinuation due to adverse reactions was reported in 2.7% (n=5) of patients receiving Endari. …
Source: FDA drug label, Emmaus Medical, Inc., effective June 20, 2025 (SPL set d5a783f4-12ef-4326-8faa-40018e45ba3b), via openFDA; the full label on DailyMed
What do FAERS reports show?
4,739 reports list glutamine among the medicines taken, each a report of something that happened, not proof the medicine caused it; 142 are coded as a death and 1,787 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 18 reactions below, 7 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?
- Glutamine: 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