Introduction: Pemetrexed is a pharmacotherapeutic cornerstone in the treatment of non-small cell lung cancer. As it is primarily eliminated by renal excretion, adequate renal function is essential to prevent toxic exposure. There is growing evidence for the nephrotoxic potential of pemetrexed, which even becomes a greater issue now combined immuno-chemotherapy prolongs survival. Therefore, the aim of this study was to describe the incidence of nephrotoxicity and related treatment consequences during pemetrexed-based treatment. Methods: A retrospective cohort study was conducted in the Jeroen Bosch Hospital, Den Bosch, the Netherlands. All patients that received at least 1 cycle of pemetrexed based therapy were included in the dataset. The primary outcome was defined as a ≥25 % reduction in eGFR. Additionally, the treatment consequences of decreased renal function were assessed. Logistic regression was used to identify risk factors for nephrotoxicity during treatment with pemetrexed. Results: Of the 359 patients included in this analysis, 21 % patients had a clinically relevant decline in renal function after treatment and 8.1 % of patients discontinued treatment due to nephrotoxicity. Cumulative dose (≥10 cycles of pemetrexed based therapy) was identified as a risk factor for the primary outcome measure . Conclusion:This study shows that patients on pemetrexed-based treatment are at risk of developing renal impairment. Risk significantly increases with prolonged treatment. Renal impairment is expected to become an even greater issue now that pemetrexed-based immuno-chemotherapy results in longer survival and thus longer treatment duration.

Introduction Correct interpretation of drug labels instructions (DLIs) is needed for safe use and better adherence to prescribed drugs. DLIs are often too difficult for patients, especially for those with limited health literacy. What is yet unknown, is how specific textual elements in DLIs (e.g., the presentation of numbers, or use of medical jargon) and patients’ health literacy skills are related to the comprehension of DLIs. In order to provide concrete directions for health professionals on how to optimize drug prescriptions, we performed a systematic review to summarize the available research findings on which textual elements facilitate or hinder the correct interpretation of DLIs in relation to patients’ health literacy. Method A systematic search was performed in PubMed, EMBASE, PsychINFO, and Smartcat (until April 2019) to identify studies investigating textual elements that facilitate or hinder the correct interpretation of DLIs in relation to patients’ health literacy. Results A total of 434 studies were identified of which 28 studies met our inclusion criteria. We found that textual elements contributing to the correct interpretation of DLIs were: using explicit time periods in dosage instructions, using plain language, presenting numbers in a numerical format, and providing DLIs in patients’ native language. Multistep instructions per instruction line, using abbreviations and medical jargon seem to hinder the correct interpretation of DLIs. Although health literacy was taken into account in a majority of the studies, none of them assessed the effectiveness of specific textual elements on patients’ comprehensibility of DLIs. Conclusion Based on our findings, we provide an overview of textual elements that contribute to the correct interpretation of DLIs. Optimizing the textual instruction on drug labels may increase the safety and adherence to prescribed drugs, taking into account that a significant proportion of patients has low health literacy.