1. Department of Pharmacology, Lagos State University College of Medicine, Ikeja, Lagos, Nigeria
2. Department of Medicine, Lagos State University Teaching Hospital, Ikeja, Lagos, Nigeria
3. Department of Pharmacology, Therapeutics and Toxicology, College of Medicine, University of Lagos, Idi-Araba, Lagos, Nigeria
4. Clinical Pharmacology Department, University College Hospital, Ibadan, Nigeria
5. Department of Medicine, University of Benin Teaching Hospital, Benin-City, Nigeria
6. Department of Medicine, Imo State University Teaching Hospital, Orlu, Imo State, Nigeria
7. Department of Medicine, Ahmadu Bello University Teaching Hospital, Zaria, Nigeria
8. Department of Pharmacy, Jos University Teaching Hospital, Jos, Nigeria
9. Department of Medicine, University of Maiduguri Teaching Hospital, Maiduguri, Nigeria
10. Department of Medicine, Delta State University Teaching Hospital, Asaba, Nigeria
11. National Hospital, Abuja, Nigeria
12. Federal Medical Centre, Jalingo, Nigeria