Aim: Psychosocial symptoms are observed in 30-60% of patients diagnosed with cancer. To address knowledge gaps of cross discipline treatment strategies, this study aimed to develop a tool to assist both psychology and oncology prescribers and pharmacists with identifying interactions between psychotropics and chemotherapeutics commonly used in a large, tertiary teaching hospital.
Methods: Commonly used chemotherapeutics (intravenous), antipsychotics, antidepressants and mood stabilising agents were identified. A comprehensive database of drug interactions between these agents was developed. Interactions were assigned classifications through a systematic process reviewing pharmacological data suggesting potential interactions and reported interactions in tertiary references. For each interaction, classifications were applied (no interaction, theoretical interaction, possible interaction and severe reaction), and risk mitigation strategies identified.
Results: Drug interactions of clinical significance to the clinician were identified for antidepressants (15%); antipsychotics (33%) and mood stabilisers (23%). A search of 17 antidepressants combined with chemotherapeutics (the 37 most commonly prescribed agents in our institution) yielded 629 individual drug–drug combinations in our table. There were 8 CYP450 interactions (1%), 80 QT prolonging effects (13%) and 9 pharmacodynamic cross over effects (1%). A search of 10 antipsychotics combined with chemotherapeutics yielded 370 drug–drug combinations. There were 72 QT prolonging effects (20%) and 14 pharmacodynamic effects (4%). The risk of agranulocytosis with concomitant use of Clozapine and any myelosuppressive agent also contributed a significant portion of the interactions (10%). Finally, a search of 4 mood stabilisers with chemotherapeutics yielded 148 combinations. There were 11 CYP450 interactions (7%), 8 QT prolonging effects (5%) and 16 pharmacodynamic effects (11%).
Conclusion: Development of clinically appropriate quick reference tool for psychotropics and chemotherapeutic agents intended to increased clinician awareness of potential drug interactions and encouraged pharmacist consultation. Future work will focus on broadening applicability of the tools considering outpatient dispensing of targeted therapies.