Aside from allogenic stem cell transplantation, which is rarely available and very expensive, at present there is no curative treatment for patients with SCD. The current standard of care includes treatment with Hydroxyurea and symptomatic care such as transfusions, antibiotic/analgesic treatment. Recent findings allowed the investigators to come up with a novel pharmacological target for prophylactic treatment of this group of patients. N-methyl D-aspartate receptors (NMDARs) are substantially up-regulated in circulating red blood cells (RBCs) of SCD patients. Ca2+ uptake via these non-selective cation channels has major impact on RBC hydration and facilitates polymerization of deoxygenated hemoglobin S variant in RBCs of patients. In vitro inhibition of NMDARs with Memantine caused re-hydration and largely prevented hypoxia-induced sickling in RBCs. A pilot trial MemSID (NCT02615847) was conducted in August 2015-March 2017 at the Hematology Division of University Hospital Zurich. A small cohort of adult SCD patients was treated with 20 mg Memantine daily to test safety, tolerability and efficacy of this drug and to assess the effect of Memantine on hemolytic activity and RBC stability. Pilot data reveal safety and an impressive therapeutic potential of Memantine in treating SCD patients. Due to a small number of SCD patients in Switzerland, an extended trial including larger number of adult and adolescent patients will be performed at the Pediatric Hematology Unit of the Emek Medical Center in Afula, Israel.