Multivalent cations interactions with fluoroquinolones or tetracyclines: A cross-sectional study.

Area of Science:

• Pharmacology
• Drug Interactions
• Clinical Pharmacy

Background:

• Oral fluoroquinolones and tetracyclines are susceptible to chelation interactions with divalent or trivalent cation-containing compounds (DTCCs).
• These drug-drug interactions (DDIs) can reduce the absorption and efficacy of these antibiotics.

Purpose of the Study:

• To determine the prevalence of DDIs between oral fluoroquinolones or tetracyclines and DTCCs in an inpatient setting.
• To assess the rate of simultaneous administration and inappropriate separation of these interacting medications.

Main Methods:

• A cross-sectional study of hospitalized adults receiving oral fluoroquinolones or tetracyclines concurrently with DTCCs in 2019.
• Data were collected from electronic health records and handwritten medication administration records (MARs).
• Primary outcome: percentage of simultaneous administration; Secondary outcome: percentage of inappropriate separation time.

Main Results:

• Out of 47 patients studied, 26.6% received interacting DTCCs.
• Ciprofloxacin was the most frequent interacting antibiotic (61.7%), followed by moxifloxacin (25.5%) and doxycycline (12.8%).
• Most patients (74.5%) received interacting medications simultaneously, and 2.1% had inappropriately separated administration times.

Conclusions:

• A high prevalence of simultaneous co-administration of oral fluoroquinolones/tetracyclines with polyvalent cations was observed, despite being a known contraindicated DDI.
• Antimicrobial stewardship programs should address this DDI.
• Further research is needed to evaluate practical solutions for mitigating this interaction in clinical practice.