Patient description: The patient is a 34-year-old African American man with the known history of Sickle cell disease comes to the clinic with severe bone pain. The patient had severe pain in his lower back that radiated to both thighs scored 9 out of 10. The patient has had positive history of sickle cell crises since childhood. He also had the same symptoms in past two weeks treated with oxycodone which was not beneficial to his pain. His PCP sent him to the emergency department to receive intra venous pain modulators. The patient is afebrile within the normal blood pressure. No splenomegaly was detected in the physical exam. He has no positive history of drug allergy. He won't smoke or uses any illicit drugs. The lab study is as bellow: Hgb: 8 g/dl WBC: 10000 /mm3 Plt: 300000 /ml MCV: 106 fL Hemoglobine electrophoresis: 91% HbS 6%HbF 3%HbA2 AST: 22 U/L ALT: 43 U/L Alk P: 53 U/L Ferritin: 1200 ng/ml

Clinical trial eligibility criteria: eligible ages (years): 20.0-45.0,  Healthy Subjects may be entered in the study only if they meet all of the following 1. Male with suitable veins for cannulation or repeated venipuncture, and must be able to swallow the study drug intact; 2. Aged between 20 and 45 years (inclusive) at the screening visit; 3. Has normal hematology results at screening visit WBC: 3.54 ~ 9.06X10^3/μL RBC: 4 ~ 5.52X10^6/μL hemoglobin: 13.2 ~17.2 g/dL hematocrit: 40.4 ~ 51.1% platelet: 148 ~ 339X10^3/μL 4. Has normal biochemistry results at screening visit alkaline phosphatase: 34 ~ 104 U/L total bilirubin: 0.3 ~ 1.0 mg/dL AST: 8 ~ 31 U/L ALT: 0 ~ 41 U/L  Subjects must not satisfy any of the following 1. Has a body weight less than 50 kg and/or body mass index (BMI) less than 18 kg/m^2 or greater than 30 kg/m^2 at the screening visit. Body mass index is determined as total body weight/height^2 (kg/m^2); 2. Is not in good general health as judged by the Investigator based on medical history, vital signs, physical examination, ECG, laboratory tests, and urinalysis at the screening visit or prior to administration of investigational product; 3. Has a history or presence of any disease or condition known to interfere with the absorption, distribution, metabolism, or excretion of drugs at the screening visit or prior to administration of investigational product; 4. Has a clinically significant psychiatric, renal, hepatic, cardiovascular, gastrointestinal, or neurologic disease at screening or prior to administration of investigational product; 5. Is a smoker and/or has used nicotine-containing products within the last 6 months prior to the screening visit; 6. Has a history of alcohol and/or drug abuse; 7. Participation of any clinical investigation during the last 60 days; 8. Blood donation of more than 250 mL within the past 12 weeks; 9. Excessive intake of caffeine containing drinks or food (more than 6 units of caffeine per day). One caffeine unit is contained in the following items: 1 (177.4 mL) cup of coffee, 2 (354.9 mL) cans of cola, 1 (354.9 mL) cup of tea, ½ (118.3 mL) cup of energy drink (e.g., B Liq. or Liq.) or 3 oz of chocolate; 10. Use of drugs with enzyme inducing properties such as St. John's Wort within 4 weeks prior to dosing; 11. Has used prescription or nonprescription medication (except for occasional use of paracetamol and nasal spray) or herbal remedies or vitamins or minerals within 2 weeks or 5 half-lives of the drug, whichever is longer, prior to dosing; 12. Any intake of grapefruit, grapefruit juice, Seville oranges, Seville orange marmalade, or other products containing grapefruit or Seville oranges within 7 days of the first administration of study medication; 13. Male subjects who are unwilling to use barrier contraception in addition to having their partner use another method of contraception, for the duration of the study and for 3 months after dosing; 14. Has a positive result on screening for serum hepatitis B surface antigen (HBsAg), hepatitis C antibody (HCV Ab), or human immunodeficiency virus (HIV); 15. Has received a blood transfusion within the last 6 months at screening; 16. Involved in the planning or conduct of the study