PS-085 Drug interactions of tyrosine kinase inhibitors used in the treatment of non small cell lung cancer

Abstract

Background Erlotinib, gefitinib and crizotinib are tyrosine kinase inhibitors (TKIs) used in the treatment of non-small cell lung cancer (NSCLC). Their hepatic metabolism involves several cytochrome p450 isoenzymes, making them susceptible to potential interactions. Purpose To identify and analyse potential interactions between TKI and the patients’ home treatment, and to determine the degree of acceptance of recommendations by the clinician. Materials and methods In our prospective study, we selected all patients with NSCLC treated with TKIs using the Pharmacy Landtools software, monitoring them over a period of six months. Sociodemographic, clinical and home treatment (HT) data were obtained through electronic medical histories. HT was confirmed by interviewing patients. The interactions were consulted in the SPC, the Micromedex and Lexicomp databases and related scientific articles. Results 19 patients were studied (31.58% men and 68.42% women) with a median age of 71 years (aged 46–83). 11 patients were treated with gefitinib, 5 with erlotinib and 3 with crizotinib. 18 potential interactions were detected, distributed as follows: 44.44% gefitinib and 27.78% erlotinib and crizotinib, respectively. 75% were due to the use of proton pump inhibitors. Of these interactions, only those considered relevant were reported (72.22%). 92.31% recommendations were accepted, resulting in substitution (83.33%) or withdrawal (16.67%) of the drug. During our intervention period, no side effects related to a drug-drug interaction were detected. Conclusions Although TKI interactions are described in the literature, they are not always detected by the clinician. It is essential to detect, report and improve patients’ drug treatment, preventing these potential interactions which may result in adverse effects or in lack of effectiveness of the antitumor treatment. No conflict of interest.