Importance of Drug-Drug Interactions in Cancer Therapy
Drug-drug interactions are an important consideration for patients undergoing cancer therapy as they often receive several drugs (oral or intravenous) as part of their anti-cancer therapy regimen, as well as additional therapies to manage comorbidities and side effects of therapy.1 In addition, with the mean age of cancer patients increasing, older patients may be at higher risk for drug interactions as they have more comorbidities which require additional drug therapy.2-4 In addition to age- and comorbidity- associated changes in drug absorption that are common in older patients.
Nearly 60% of patients undergoing cancer therapy (regardless of mode of administration) are estimated to have had at least one potential drug-drug interaction.5 For patients receiving oral anticancer therapy, up to 50% have been reported to experience a potential drug-drug interaction, with 16% experiencing a major event.4 In addition, ~30% of drug-drug interactions associated with anticancer therapy required medical intervention,6 and drug-drug interactions are estimated to be the cause of death of ~4% of patients with cancer.7
When coadministered with anticancer therapies, drug-drug interactions occur most frequently with coumarin, quinolones, antiepileptics, hydrochlorothiazide and opioids.4-6 Pharmacodynamic drug-drug interactions may cause QT prolongation, gastrointestinal toxicity and central nervous system depression.4-6
The risk of drug interactions is increased in certain patient groups, including patients using over-the-counter medications, patient subgroups with increased risk of drug interactions are:3-5
- Patients who take multiple medications.
- Patients using over-the-counter drugs or complimentary medicines.
- Patient cancer type.
- Riechelmann RP, Tannock IF, Wang L et al. Potential drug interactions and duplicate prescriptions among cancer patients. J Natl Cancer Inst 2007; 99: 592-600.
- Yancik R, Ries LA. Aging and cancer in America. Demographic and epidemiologic perspectives. Hematol Oncol Clin North Am 2000; 14: 17-23.
- Scripture CD, Figg WD. Drug interactions in cancer therapy. Nat Rev Cancer 2006; 6: 546-558.
- van Leeuwen RW, Brundel DH, Neef C et al. Prevalence of potential drug-drug interactions in cancer patients treated with oral anticancer drugs. Br J Cancer 2013; 108: 1071-1078.
- 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.
- Buajordet I, Ebbesen J, Erikssen J et al. Fatal adverse drug events: the paradox of drug treatment. J Intern Med 2001; 250: 327-341.