[1] Univ Orange Free State, Dept Pharmacol, ZA-9300 Bloemfontein, South Africa
[2] Univ Cape Town, Dept Med, ZA-7700 Rondebosch, South Africa
[3] Rhodes Univ, Dept Pharmacol, Grahamstown, South Africa
[4] Dept Hlth, Therapeut Training Program, Durban, South Africa
[5] Univ Ghana, Dept Med, Ctr Trop Clin Pharmacol & Therapeut, Legon, Ghana