Pharmacokinetic (PK) Study of Tafenoquine in Healthy Adults

Inclusion Criteria: 1. Age 18-65 at the time of consent, weighing between 132 and 250 pounds 2. Ability and willingness to sign informed consent 3. Available for the study period 4. Willing to use contraception for the duration of the study 5. Agree not to take over the counter antioxidants, vitamin C or vitamin E, 2 weeks prior to dosing and 7 days post dosing Exclusion Criteria: 1. Women: positive urine pregnancy test at screening or day of dosing 2. Women who are lactating or intend to become pregnant during the study period. 3. Acute or chronic clinically significant hematologic, pulmonary, cardiovascular, hepatic, or renal functional abnormality as determined by medical history, physical examination or laboratory screening. 4. History of allergic reaction to tafenoquine or primaquine. 5. Scheduled receipt of any vaccine 1 week prior to or after 4 weeks tafenoquine dosing. Routine COVID and influenza vaccination will be allowed outside of this timeframe. 6. Currently taking metformin, dofeltilide or other medication with known multidrug and toxin extrusion enzyme (MATE) metabolism. 7. Known or suspected congenital or acquired immunodeficiency; or receipt of immunomodulation therapy such as anti-cancer chemotherapy or radiation therapy. 8. Diagnosis with Bipolar Disorder or Schizophrenia, hospitalization in the past year for a mental health disorder, or any other psychiatric condition, which in the opinion of the investigator prevents the participant from participating in the study. 9. Participants with hemoglobin, Creatinine, BUN, Albumin, eGFR; ALT, and AST of grade 2 or greater. Any exclusionary lab abnormality may be repeated once. If a repeat screening blood test is performed, only the result of the second test will be reviewed and used to determine eligibility. 10. G6PD result not normal or \< 70% activity 11. Significant screening physical examination abnormalities or chronic medical condition that in the opinion of the investigator may impact participant safety, including BMI \> 35kg/m2 12. Participation (active or follow-up phase) or planned participation in another vaccine, or drug, in the 4 weeks prior to or during the trial 13. Beliefs that bar the administration of blood products or transfusions 14. Clinician discretion