1. Department of Medicine & Therapeutics School of Medicine & Dentistry, College of Health Sciences, University of Ghana, Accra, Ghana;
2. Pain and Palliative Medicine Department, Federal Medical Centre, Abeokuta, Nigeria;
3. Department of Radiotherapy and Oncology, Ahmadu Bello University Teaching Hospital, Zaria, Nigeria;
4. Global Drug Policy Observatory, University of Swansea, Swansea, UK