Factors associated with prescribing restriction on oncology formulary drugs in Malaysia

Background Drugs listed on formularies are often subjected to a variety of utilization restriction measures. However, the degree of restriction is influenced by multiple factors, including the characteristics and attributes of the listed drugs. Objective To identify the factors that are associated with the levels of prescribing restriction on oncology formulary drugs in Malaysia. Setting Oncology formulary in Malaysia. Method The Malaysia Drug Code assigned to each of the drug products on the Malaysia Ministry of Health (MOH) drug formulary was used to identify oncology drugs belonging to WHO ATC class L (antineoplastic and immunomodulating agents). Main outcome measures Categories of prescribing restrictions, therapeutic class, drug type, administration mode, number of sources and the post-approval use period. Results Oncology drugs having a shorter post-approval use period (p < 0.001), biologic oncology drugs (p = 0.01) and oncology drugs belonging to immunosuppressant therapeutic class (p = 0.03) were all significantly associated with a greater likelihood of being subjected to a higher level of prescribing restriction. Conclusion This study suggests that safety concerns, costs and potentials for inappropriate use were the important considerations influencing a higher level of prescribing restriction placement on oncology drugs in the Malaysia MOH drug formulary.