About Dr Orrell

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MBChB (Hons), MSc (Clin Pharmacol), MMed (Clin Pharmacol), PhD (Medicine)


HIV Management Diploma, Diploma in Child Health.


I am a Clinical Pharmacologist, HIV Clinician and Clinical Trial Specialist with particular interest in the rational prescription and use of medication; as well as patient adherence to treatment..


I completed my MBCHB degree at the University of Cape Town and specialised in Clinical Pharmacology under Professor Peter Folb; completing my Masters on the rational use of medication by nurse prescribers in 1998 and my MMed thesis in 2000. I am passionate about the improving the appropriate use of medication, both by prescribers and by patients.


Since 2000 I have worked at the Desmond Tutu HIV Foundation, managing people living with HIV. Much of my work has involved leadership of Phase I to III clinical trials focused on development of new antiretroviral therapy and treatment strategies. My personal research interest and passion has remained focused on improving the use of medication: including novel methods of monitoring tablet taking behavior and research into improving daily medication dosing as well as long term retention.

Special Interests

Rationalisation of prescriptions: including pharmacological review of complex drug interactions and potential side effects, across all medical fields including infectious disease, cardiovascular and psychiatry, in order to offer advice on simplification of current treatment regimens while maintaining efficacy.

Therapeutics: review of current evidence-based treatment guidelines to support rational use of medication at hospital level.

Adherence support: monitoring of adherence behaviour to identify areas of risk; and provide support in improvement of tablet taking behaviour.

HIV management: I have extensive experience in the clinical care of people living with HIV as outpatients, including selecting and supporting current choices in antiretroviral therapy, managing personal and circumstantial issues with adherence and making medication decisions with HIV resistance.

Clinical Trials: I have experience as principal investigator across the clinical trial spectrum; including pharmaceutical and investigator-driven phase I to III studies.



Successful leadership, growth and management of three internationally-funded research sites; First or last author of 20 peer-reviewed articles in high impact medical journals; and co-author on 42 others. Co-editor of a number of editions of the South African Medicines Formulary (including anti-infectives, haematology and chemotherapeutics). Setting up of first large antiretroviral clinic in Gugulethu Cape Town; with early contributions to both local and national antiretroviral treatment guidelines. Ongoing contributions on adherence and ART resistance South African HIV Clinician Society guidelines.


Publications by Doctor Orrell

Academic Papers
HIV Education Programme