Comprehensive medication guide to Glutamine including estimated pricing, availability information, side effects, and how to find it in stock at your local pharmacy.
Estimated Insurance Pricing
$10/month for commercially insured patients enrolled in the Emmaus copay assistance program; $0–$150 copay range for other commercially insured patients on Tier 5; Medicare Part D Tier 5 with $2,000 annual OOP cap effective 2025.
Estimated Cash Pricing
$3,200–$3,471 retail per 30-day supply (180 packets); as low as $1,013 with a GoodRx coupon at participating specialty pharmacies.
Medfinder Findability Score
42/100
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Glutamine, sold under the brand name Endari, is an FDA-approved prescription medication for sickle cell disease (SCD). It is a pharmaceutical-grade form of L-glutamine, an amino acid that the body normally produces but that sickle red blood cells have difficulty utilizing effectively. Endari was approved by the FDA in July 2017 — the first new treatment for sickle cell disease in nearly 20 years and the first treatment ever approved specifically for pediatric SCD patients ages 5 and older.
Prescription Glutamine comes in 5-gram foil packets of white crystalline powder, dispensed exclusively through specialty pharmacies. It is taken orally twice daily, mixed with a cold or room-temperature beverage or soft food immediately before ingestion. The first FDA-approved AA-rated generic version was launched by ANI Pharmaceuticals in July 2024.
The Phase 3 clinical trial demonstrated that Glutamine reduced the median number of pain crises from 4 to 3 over 48 weeks (p=0.005) and reduced hospitalizations by 33% compared to placebo. In that trial, 63.4% of patients were also taking hydroxyurea, confirming the safety and tolerability of combination use.
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Sickle cell disease causes abnormally-shaped red blood cells that are prone to oxidative damage — a process in which harmful molecules called reactive oxygen species (ROS) injure cell membranes and accelerate the sickling process. Sickle red blood cells have a lower NAD redox potential than normal red blood cells, meaning they have weaker antioxidant defenses.
Glutamine works by improving the NAD redox potential in sickle red blood cells. When taken orally, L-glutamine is absorbed into the bloodstream and taken up by red blood cells, where it is used to synthesize glutathione — one of the body's most powerful antioxidants — and provides precursors for NAD synthesis. This improved antioxidant capacity reduces oxidative damage to sickle cells, helping them remain more flexible and less prone to clumping in blood vessels.
The FDA notes that the precise mechanism of action has not been fully characterized. In vivo studies demonstrated that L-glutamine supplementation improved NAD redox potential in sickle red blood cells, which is the theoretical basis for its therapeutic effect. Unlike hydroxyurea, which reduces sickling by increasing fetal hemoglobin (HbF), Glutamine targets the downstream oxidative damage caused by sickling — making the two drugs complementary when used together.
5g per packet — oral powder
For patients under 30 kg (66 lbs): 1 packet (5g) twice daily = 10g/day
10g (2 packets) — oral powder
For patients 30–65 kg (66–143 lbs): 2 packets (10g) twice daily = 20g/day
15g (3 packets) — oral powder
For patients over 65 kg (143 lbs): 3 packets (15g) twice daily = 30g/day (maximum dose)
Finding Glutamine can be significantly challenging for patients, despite the absence of an active FDA shortage. The primary barrier is its specialty-only distribution model: Glutamine is classified as a specialty medication and can only be dispensed through specialty pharmacies — not standard retail chains like CVS or Walgreens general counters.
A real-world study found that 33% of patients prescribed L-glutamine never filled their prescription, and only 21% were actively taking it after 10 months of follow-up. Insurance prior authorization requirements, step therapy mandates, high specialty tier cost-sharing, and the limited specialty pharmacy network are the primary access barriers. The launch of a generic version in July 2024 may gradually improve availability and pricing.
If you're struggling to fill your Glutamine prescription, medfinder can help. medfinder calls specialty pharmacies in your area to find which ones have Glutamine in stock and can fill your prescription — results are sent to you by text, saving you hours of phone calls.
Glutamine (Endari) is not a controlled substance and has no DEA scheduling restrictions. Any licensed healthcare provider with prescribing authority can write a prescription for Glutamine. In clinical practice, prescribers typically include:
Hematologists — Primary experts in sickle cell disease; most commonly the prescribing specialist for SCD medications
Pediatric hematologists / oncologists — For pediatric SCD patients (ages 5+); approved for children in the FDA labeling
Oncologists — Particularly those with experience in hematologic disorders
Primary care physicians (PCPs) — Can prescribe when experienced with SCD or in coordination with a hematologist
Pediatricians — For younger patients with SCD; often in collaboration with a pediatric hematology team
Nurse practitioners (NPs) and physician assistants (PAs) — Can prescribe within their scope of practice, often within hematology or SCD clinics
Telehealth prescribing of Glutamine is available. Since Glutamine is not a controlled substance, it can be prescribed via virtual appointment in most states. Emmaus Medical has partnered with telehealth platform providers to enable online prescribing and home delivery of Endari, making it accessible to patients in areas with limited specialty SCD care.
No. Glutamine (Endari) is not a controlled substance. It is an amino acid — a naturally occurring nutrient — and is not subject to DEA scheduling or the restrictions that apply to controlled medications such as stimulants, opioids, or benzodiazepines.
Because Glutamine is not a controlled substance, it can be prescribed by any licensed healthcare provider with prescribing authority — including primary care physicians, pediatricians, nurse practitioners, and physician assistants — without special DEA licensing. It can also be prescribed via telehealth in most states, and refills are not subject to controlled substance refill limits.
While Glutamine itself is not controlled, it does require a prescription (it is not available over the counter for the SCD indication) and is dispensed exclusively through specialty pharmacies. The OTC form of L-glutamine available at health food stores and vitamin shops is not pharmaceutically equivalent and is not FDA-approved for sickle cell disease.
The following side effects occurred in more than 10% of patients in clinical trials and are considered common:
Constipation
Nausea
Headache
Abdominal pain
Cough
Pain in extremities (hands and feet)
Back pain
Non-cardiac chest pain
Seek immediate medical attention for these serious reactions:
Severe allergic reaction: Signs include rash, hives, difficulty breathing, facial swelling, rapid heartbeat. Stop taking Glutamine and seek emergency care immediately.
Hypersplenism: Rare; report symptoms of fatigue, left upper abdominal fullness, or worsening anemia to your doctor.
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Hydroxyurea (Droxia, Siklos, Hydrea)
First-line SCD therapy approved since 1998; increases fetal hemoglobin to reduce sickling. Oral tablet, once daily. Generic widely available. Often prescribed together with Glutamine.
Crizanlizumab (Adakveo)
P-selectin inhibitor approved 2019 for ages 16+; IV infusion monthly. Reduces VOC frequency through a different mechanism than Glutamine. May be used alongside Glutamine or hydroxyurea.
Casgevy (exagamglogene autotemcel)
First CRISPR gene editing therapy approved Dec 2023; potentially curative for SCD. One-time treatment. Available only at specialized treatment centers. Very different from Glutamine — not a daily medication.
Lyfgenia (lovotibeglogene autotemcel)
Gene therapy approved Dec 2023; another curative-intent option for SCD. One-time treatment at specialized centers. Like Casgevy, a fundamentally different intervention compared to ongoing Glutamine therapy.
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Hydroxyurea
minorNo significant interaction. Used concurrently in 63.4% of Phase 3 trial patients without notable safety concerns. Works through a different mechanism; safe to combine.
Crizanlizumab (Adakveo)
minorLimited data on combination use. Both approved for SCD with different mechanisms. Some patients take both. Consult prescriber.
Opioid pain medications
minorNo known pharmacokinetic interaction. Glutamine is preventive, not a rescue analgesic. Disclose all pain medications to your provider.
NSAIDs (ibuprofen, naproxen)
minorNo known direct interaction. Caution in patients with renal impairment as NSAID use may affect kidney function and Glutamine safety has not been established in renal impairment.
OTC L-glutamine supplements
moderateTaking OTC glutamine supplements alongside prescription Endari may increase total glutamine intake beyond intended doses. Not recommended without medical guidance.
Glutamine (Endari) represents an important treatment option for sickle cell disease patients who continue to experience pain crises despite hydroxyurea therapy, or who cannot tolerate hydroxyurea. It was a landmark FDA approval in 2017 — the first new SCD drug in nearly two decades — and the Phase 3 trial demonstrated meaningful reductions in pain crises (25%) and hospitalizations (33%).
The greatest challenge with Glutamine is access. The specialty pharmacy distribution model, high cost without assistance, and complex insurance requirements mean many patients who have a prescription never successfully fill it. However, the Emmaus copay assistance program ($10/month for commercially insured patients), the Endari Support Program for uninsured patients, and discount coupons (GoodRx ~$1,013/month) provide real options for reducing this barrier.
If you're struggling to find a pharmacy that has Glutamine in stock, medfinder can help. Our service calls pharmacies near you to check availability, so you don't have to spend hours on hold. Enter your medication, dosage, and location — and we'll text you the results.
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