L Glutamine for Sickle Cell Disease

L glutamine is an oral amino acid supplement licensed in some regions to reduce acute complications of sickle cell disease in patients aged 5 years and over. It lowers the frequency of pain crises and hospital admissions modestly and can be used with or without hydroxyurea.

Classification. Amino acid; antisickling and antioxidant adjunct.

Mechanism. Raises the reduced to oxidised nicotinamide adenine dinucleotide ratio in sickle red cells, which lessens oxidative damage, adhesion and haemolysis.

Pharmacokinetics. Absorbed in the small intestine and metabolised by the usual amino acid routes. Half-life is about 1 hour, and no dose-linked organ accumulation is described.

Sickle cell disease, to reduce acute complications (age 5 years and over).

• Dose by weight, taken orally twice daily: under 30 kg, 5 g; 30 to 65 kg, 10 g; over 65 kg, 15 g.
• Maximum: 30 g daily. Loading dose: none. Titration: none; the weight band sets the dose.
• Duration: long-term; reassess benefit after 6 to 12 months by crisis frequency and admissions.
• Positioning: add-on for patients who still have crises on an optimised hydroxyurea dose, or who cannot take hydroxyurea.

Adjustments. Kidney: use with care in severe impairment, with limited data. Liver: use with care, as raised liver enzymes and hepatic reactions have been reported. Pregnancy and breastfeeding: no adequate data.

Contraindications. Hypersensitivity.

Adverse effects. Constipation, nausea, headache, abdominal pain, cough, pain in the extremities, back pain, chest pain. Hypersplenism and splenomegaly have been reported. Hepatic and renal events are uncommon.

Interactions. None important; it can be taken with hydroxyurea, folic acid and penicillin prophylaxis. Cytotoxic drugs and drugs affecting glutamine metabolism call for specialist review.

Pregnancy and breastfeeding. Avoid unless the benefit clearly outweighs the risk.

Regional points. Supply in East Africa is limited. Hydroxyurea, penicillin prophylaxis, malaria prevention and vaccination remain the core of care; L glutamine does not replace them.

Common errors. Under-dosing by weight band; using it instead of hydroxyurea; mixing in a hot drink.

Administration. Mix each powder packet (5 g) in 240 mL of a cold or room-temperature drink, or in 120 to 180 mL of soft food, and take immediately. Do not mix in hot liquids.

Baseline. Full blood count, liver and kidney function, record of crisis frequency and admissions in the previous year.

Monitoring. Crisis diary and admissions every 3 months; liver and kidney function every 6 months; full blood count and spleen size at each visit.

Referral and escalation. Refer rising spleen size, abnormal liver enzymes or persistent crises to haematology, and review hydroxyurea dose, adherence and alternative treatments.