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“I Like Solving Medication Puzzles”

Femke de Velde
“I Like Solving Medication Puzzles”

Femke de Velde is a hospital pharmacist Quality Assurance at the Leiden University Medical Center (LUMC) in Leiden, The Netherlands. Femke chose to work in the field of pharmacy for its versatility. “I like to solve the puzzles about medication: to answer the questions of physicians and nurses, to formulate accurate dosing advice for special patient groups”.

A Path in Pharmacy

Femke began her career in Pharmacy in 2003, when she started the Pharmacy Study at the University of Groningen, the Netherlands, from which she graduated in 2009. She got her first job in a hospital in 2010, at the Maasstad Hospital in Rotterdam where she worked until 2014 as a hospital pharmacist trainee. After finishing this training,  Femke started a combination job of 50% PhD and 50% hospital pharmacist at the Erasmus Medical Center in the same city, until 2018. It was here that Femke was introduced to the COMBACTE project by her PhD supervisor, the late Prof. Johan Mouton. Femke has been part of COMBACTE-NET’s statistical network STAT-Net since 2014. Currently she works at the LUMC, and plans to defend her PhD thesis in the summer of 2020.

Prof. Mouton was Femke’s PhD supervisor until last year. “He is greatly missed, not only because of his knowledge, but also as an inspiring and enthusiastic supervisor. I highly appreciated our scientific discussions and his feedback on my papers. Also on a personal level, I have warm memories” says Femke.

During her time in COMBACTE, Femke has been lead author for three scientific papers (two of them published in the Journal of Antimicrobial Chemotherapy –1 & 2 -, and one in Clinical Pharmacokinetics), and contributed to one STAT-Net white paper (published in Clinical Infectious Diseases Journal). Her most recent one on imipenem – which will be followed by a second – can be found here.

“What I liked most about working on these papers was to search for an answer to our research questions. Pharmacokinetics (PK) describes the behavior of drugs and metabolites in the body in terms of absorption, distribution, metabolism and elimination. Pharmacodynamics (PD) describes the relationship between concentrations and effects.”

— Femke de Velde

Optimizing dosing via PK/PD modelling

“Modelling of PK/PD can support dosing optimization with the objectives to maximize efficacy and minimize resistance and toxicity. We developed several population PK models for old antibiotics (amoxicillin, clavulanic acid and imipenem) to evaluate and improve dosing regimens. These antibiotics were developed decades ago when PK/PD principles were largely unknown and sophisticated population PK methods did not exist. So in fact, we redeveloped the dosing of these agents”.

Amoxicillin, clavulanic acid and imipenem

“Amoxicillin alone and amoxicillin with clavulanic acid are the most consumed antibiotics in the majority of European countries, but their population PK is poorly studied. It is therefore unknown if their dosing is optimal. We developed popPK models to optimize dosing for these frequently used antibiotics.

Imipenem dosing in the product information is not developed for critically ill patients. As they have an altered PK than non-critically ill patients, the dosing in the product information might therefore not be extrapolated to critically ill patients. A few imipenem population PK models in critically ill patients has been previously published using several popPK software. The popPK parameters of these models differ remarkably. Therefore, we developed two popPK models of imipenem, using parametric and nonparametric popPK software. We compared both popPK models and we studied the influence of the modelling differences on dosing recommendations following from these models.”

Future papers

“I will submit the second imipenem paper soon (on behalf of COMBACTE). I am also currently working on a small PK study about intravenous amoxicillin in renally impaired patients (not on behalf of COMBACTE). The latter paper will be a poster at ECCMID 2020”.

After she defends her PhD Femke plans to still write scientific papers.  “I will however first focus on my job as a hospital pharmacist and my family”.