Recommendations for the prevention of drug-drug interactions associated with kinase inhibitor therapies are based on practices utilised in clinical studies, post-marketing experience and reports and empirical results based on clinical experience, including those of the authors. In all instances, patient education is an important component of management.
Collaboration with Other Healthcare Professionals and Specialists1,2
It is extremely important that there is good communication between the prescribing oncologist and the pharmacist and that everyone knows exactly what other medications the patient is taking. It is also important that the pharmacist uses programs or centralised databases that detect potential harmful drug interactions (or performs this analysis manually if computer programs are unavailable) and contacts the medical oncologist so that if there is a possible drug-drug interaction together they can prescribe alternative medications. To perform an analysis on drug-drug interactions, it is key for the community pharmacist to have access to information on all of the medications the patient is taking, including OTC drugs, in addition to the kinase inhibitor.
Documentation of All Drugs in One Drug Database (Including Chemotherapy)
Ideally, all drugs (including herb- and OTC drugs) prescribed by oncologists, general practitioners and other healthcare professionals should be documented electronically in one national database. Such records should include information on the patient’s medical status, in computer-based patient records to help identify and prevent any potentially harmful DDIs.2 A medication review, before, and during anti-cancer therapy is very important.2
Therapeutic Drug Monitoring
Therapeutic drug monitoring is defined as the measurement of drug in biological samples to individualise treatment by adapting drug dose to improve efficacy and/or reduce toxicity.3,4 This approach should be considered if a drug interaction is suspected, in case of toxicity, or lack of satisfactory clinical response.5 The clinical significance of therapeutic drug monitoring in oncology, and especially with oral agents, should be explored in the near future.
Adherence
Adherence to kinase inhibitors maximizes their effectiveness and minimizes any potential toxicities. Interventions to improve adherence to oral chemotherapy regimens include:6
- Communication about the importance of adherence and the potential consequences of nonadherence
- Simplification of the patient's medication schedule
- Inclusion of a caregiver or family member in the conversation.
- Written materials should always be provided to accompany verbal instructions.
- Information on correct storage and intake should be given
References
- van Leeuwen RW, Swart EL, Boven E et al. Potential drug interactions in cancer therapy: a prevalence study using an advanced screening method. Ann Oncol 2011; 22: 2334-2341.
- van Leeuwen RW, Jansman FG, van den Bemt PM et al. Drug-drug interactions in patients treated for cancer: a prospective study on clinical interventionsdagger. Ann Oncol 2015; 26: 992-997.
- Bardin C, Veal G, Paci A et al. Therapeutic drug monitoring in cancer--are we missing a trick? Eur J Cancer 2014; 50: 2005-2009.
- Mathijssen RH, Sparreboom A, Verweij J. Determining the optimal dose in the development of anti-cancer agents. Nat Rev Clin Oncol 2014; 11: 272-281.
- Haouala A, Widmer N, Duchosal MA et al. Drug interactions with the tyrosine kinase inhibitors imatinib, dasatinib, and nilotinib. Blood 2011; 117: e75-87.
- McCue DA, Lohr LK, Pick AM. Improving adherence to oral cancer therapy in clinical practice. Pharmacotherapy 2014; 34: 481-494.