Drug substitution in community pharmacies in Kampala city, Uganda. A descriptive study

Abstract

Background In Sub-Saharan Africa where Uganda lies, half of the population lacks reliable access to essential medicines and out of pocket expenditure by patients is as high as 34%. Generic drug substitution, if implemented safely and appropriately can play a key role in reducing the cost of medicines. It is thus important to examine the extent to which drug substitution is utilised in Uganda.

Objectives This study assessed drug substitution in community pharmacies in Kampala city by specifically determining the prevalence, describing the practice and determining the perception of dispensers in community pharmacies towards drug substitution.

Methods A self administered questionnaire was used to collect data from a stratified random sample of 133 community pharmacies across the different divisions of Kampala city. Data were analysed and information generated was presented using descriptive statistics. Mystery buyers were also used to corroborate the prevalence of drug substitution obtained using the questionnaire. Trained research assistants visited 173 community pharmacies participating in the study one week before data collection with the questionnaire. They presented at the pharmacy with study developed prescriptions as simulated patients with a view of eliciting drug substitution occurrences.

Results Prevalence of drug substitution reported by the questionnaire was higher (96%, n=133) than that obtained from the mystery buyer (47%, n=173). Both methods showed the same pattern as far as practice of the various forms of drug substitution. The most prevalent form of drug substitution practiced was innovator-generic at 85% (n=133) and 71% (n=45) of the pharmacies using the questionnaire and mystery buyers respectively. This was followed by generic-generic brand substitution at 82% (n=133) and 57% (n=42) of the pharmacies using the questionnaire and mystery buyers respectively.

Majority (92%, n=133) of the pharmacies substitute over the counter drugs while 56% substitute medicines with prescriptions. Dispensers in majority of the pharmacies (75%, n=133) indicated that price of the drug is one of the considerations they put in mind when performing drug substitution.

Dispensers in majority of pharmacies (82%, n=133) perceive drug substitution as appropriate in ‘most cases’ but there are some situations where it is not. Knowledge of drug substitution policy was limited as 61% (n=133) of community pharmacy dispensers believe Uganda has no policy on drug substitution.

Conclusions and recommendations This study found a high prevalence of innovator-generic brand and generic-generic brand drug substitutions in community pharmacies in Kampala city. Drug substitution is carried out for both over the counter and medicines with prescriptions. Price is the main consideration for carrying out drug substitution. Dispensers in majority of the community pharmacies perceive drug substitution as acceptable in ‘most cases’ but there are certain situations where it is not. Given the wide spread generic-generic brand substitution in community pharmacies, there is risk of substituting generic brands with other generic brands that may not be bioequivalent. To ensure that this does not endanger patient’s lives we recommend post-marketing surveillance, spearheaded by the National Pharmacovigilance Centre, in community pharmacies to detect any therapeutic in-equivalence. Findings from the monitoring should be used to delineate therapeutic failure that may occur due to therapeutic in-equivalence as opposed to that due to substandard medicine products.