A pharmacist-researcher based at Midwestern University's Downers Grove campus spent three and a half years coordinating 19 international experts to develop new guidance for antibiotic dosing in critically ill patients.

The result: individualized dosing nearly doubled the likelihood of a successful clinical outcome compared with standard treatment.

Dr. Nathaniel "Jim" Rhodes, a professor of pharmacy practice at Midwestern University's College of Pharmacy and clinical and computational science lead for the university's Pharmacometrics Center of Excellence, co-chaired the panel alongside Erin Barreto of Mayo Clinic. Their consensus guidance was published in Pharmacotherapy, the official journal of the American College of Clinical Pharmacy, and has been endorsed by seven healthcare organizations, including the Infectious Diseases Society of America.

The guidance targets beta-lactam antibiotics, a class that includes penicillins and cephalosporins. Up to 70% of patients with sepsis receive a beta-lactam antibiotic, according to Midwestern University's announcement published Wednesday, July 29.

"Most beta-lactam dosing still relies on weight and kidney function — pretty blunt instruments," Rhodes said. "Drug levels can vary 10- to 30-fold between patients even when the standard dose looks right on paper."

Two patients can receive the same dose and end up with wildly different drug levels in their blood. The new guidance recommends using patient-specific blood tests that measure antibiotic concentrations, helping clinicians tailor doses rather than relying on weight and kidney function alone. It also identifies which patients should be prioritized for individualized dosing.

Rhodes, who also practices as an infectious diseases pharmacist at Northwestern Memorial Hospital in Chicago, said the endorsement process took years for a reason. Coordinating experts across multiple countries and disciplines was lengthy, he said, but the systematic review and evidence evaluation give hospitals confidence to adopt the recommendations.

The Infectious Diseases Society of America lists the guidance on its practice guidelines page, confirming its endorsement. The full list of all seven endorsing organizations was not detailed in available materials.

The work connects to a broader effort at Midwestern University's Downers Grove campus, where the Pharmacometrics Center of Excellence focuses on developing individualized medication dosing strategies through computer modeling and lab analysis. The guidance is now available for hospital adoption.