Symptomatic sickle cell disease is worldwide the most frequent cause for hereditary hemolytic anemia with recurrent pain crisis. Hemolysis, vaso- occlusive and pain crises are hallmarks of this disease and are causative for an important socio-economic burden worldwide, especially in Africa.

Aside from allogenic stem cell transplantation, which is rarely available and very expensive, at present there is no curative treatment for patients with sickle cell disease (SCD). The current standard of care includes treatment with hydroxycarbamide and symptomatic care such as transfusions, antibiotic/analgesic treatment.

This study has the aim to study the safety and tolerability of Memantin in patients with sickle cell disease.

During the study participants will be asked if medical occurrences (AEs) happened and laboratory analysis (haematology, coagulation, chemistry) and urine samples will be taken. In addition at each visit a physical examination and measurement of vital signs will be performed.

In addition the number of hospital days and emergency consultations, the impact on working ability (the number of days with inability to work, changes in iv%), the amount and type of analgesic medication, the amount of RBC transfusions, the number of days that antibiotics prescribed and haematology (at local and external laboratory) and chemistry laboratory parameters will be assessed. For the impact on work and social life a questionnaire of quality of life will be filled out monthly by the patient.

At screening and at the end of the study SCD specific assessments will be performed, which include cardiologic examination (ECG, ECHO), abdominal sonography, ophthalmological examination, lung function testing and neuroangiologic examination.

Inclusion Criteria:

• Documented symptomatic sickle cell disease (HbSS or HbS/beta thalassemia)

  • Age 18 years or older
  • Able and willing to provide written informed consent and to comply with the study protocol procedures
  • Willing to use two effective methods of contraception during study treatment until 6 months after stop of study treatment. Effective contraception methods are considered oral, injectable, implantative contraceptives or intrauterine contraceptive devices combined with the use of condom.

Exclusion Criteria:

• History of transfusion during last three months before Screening

  • Patients with active bacterial, viral or fungal infection requiring systemic treatment
  • Patients with known infection with human immunodeficiency virus (HIV) of human T cell leukaemia virus 1 (HTLV-1)
  • Inadequate renal function: creatinine clearance < 30ml/min
  • Inadequate liver function: NCICTC Grade 3 liver function tests (AST, ALT > 5x upper limit of normal (ULN))
  • History of malignancy
  • Women who are pregnant or breast feeding
  • Previous known mental disorder or known family history of psychiatric diseases
  • Known epileptic disease
  • The receipt of any investigational product within 30 days prior to this trial