Patients in intensive care units (ICUs) are at high risk of drug–drug interactions (DDIs) due to polypharmacy. Little is known about type and frequency of DDIs within German ICUs. Clinical pharmacists’ interventions (PI) recorded in a national database (ADKA-DokuPIK) were filtered for ICU patients. Binary DDIs involving ≥1 anti-infective agent with >1 database entry were selected. A modified two-step Delphi process with a group of senior hospital pharmacists was employed to evaluate selected DDIs for clinical relevance by using a five-point scale and to develop guidance for clinical practice. In total, 16,173 PI were recorded, including 1836 (11%) DDIs in the ICU setting. Of the latter, 41% (756/1836) included ≥1 anti-infective agent, 32% (590/1836) were binary DDIs, and 25% (455/1836) were listed at least twice. This translates into 88 different DDIs, 74% (65/88) of which were rated as being clinically relevant by our expert panel. The majority of DDIs (76% [67/88]) included macrolides, antifungals, or fluoroquinolones. This percentage was even higher in DDIs being rated as clinically relevant by the experts (85% [55/65]). It is noted that an inter-professional discussion and approach is needed in the individual patient management of DDIs. The guidance developed might be a tool for decision support.

Background: The project ‘Multicenter Renal Pharmacist Group—Implementation of Pharmaceutical Care for Patients with Renal Impairment at four Non-University Hospitals in Germany’ started in the beginning of 2020 with the goal to establish high-quality pharmaceutical care to improve patient safety for hospitalized patients with renal impairment at German non-university hospitals. Pharmaceutical service quality should be optimized by intense and effective intraprofessional collaboration within the network. Methods: Over a period of two years (2020–2022), we implemented renal pharmacists (RPs) for patients with renal impairment (RI) at four non-university hospitals in Germany (Starnberg Hospital, Rudolf Virchow Hospital Glauchau, Catholic Hospital in the Märkisch District (KKiMK), and Hospital Sindelfingen-Boeblingen). The RPs conducted medication analyses identifying renal-drug-related problems (rDRPs) two to five days a week. The rDRPs, including recommendations to solve them, were forwarded to the attending physicians via written consultations or personally during ward rounds. The RPs were mentored by a renal pharmacist expert from LMU Munich and formed a multicentered team with close collaboration. Data about the RP service were collected and were retrospectively evaluated. Results: During the two-year project period, a total of 3924 patients from various disciplines were visited across all four locations. In total, 1425 patients (36.3%; with a range from 22.7 to 56.4% between hospitals) received one or more interventions by RPs concerning 2454 rDRPs (a median of one to three rDRPs per patient). In cooperation with the physicians, 77.6 to 88.2% of the rDRPs were solved. The most common causes were ‘dosage too high’ and ‘contraindication’. Conclusion: The implementation of pharmaceutical care for patients with renal impairment at four non-university hospitals in Germany increased appropriate prescribing by physicians. The multicenter team proved to be an excellent support for the newly established services.