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The Effect of Losartan on Cephalexin

The Effect of Losartan on Cephalexin

Status
Recruiting
Phases
Phase 1
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT07300670
Acronym
KEFALOS
Enrollment
12
Registered
2025-12-24
Start date
2026-03-04
Completion date
2026-05-08
Last updated
2026-03-25

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Healthy, Possible Interaction Between Losartan and Cephalexin

Keywords

losartan, cephalexin, pharmacokinetic interaction, absorption

Brief summary

The goal of this clinical trial is to investigate the effects of the blood pressure-lowering drug losartan on the blood levels and urinary excretion of the antibiotic cephalexin during simultaneous and staggered ingestion in healthy volunteers. The main questions it aims to answer are: 1. Does losartan affect cephalexin levels and excretion when ingested at the same time? 2. Does a three-hour interval between ingestion of losartan and cephalexin eliminate a possible effect? Researchers will compare the effects of losartan ingested at the same time, losartan ingested three hours prior, and no losartan ingested on oral cephalexin in each participant to see whether an interaction exists and could be avoided. Participants will visit the research laboratory on three days during which they will ingest single doses of losartan at the same time with, three hours prior to, and not at all prior to ingesting single doses of cephalexin.

Interventions

DRUGlosartan

100 mg tablet orally, single dose

DRUGcephalexin

500 mg tablet orally, single dose

Sponsors

Aleksi Tornio
Lead SponsorOTHER_GOV
Turku University Hospital
CollaboratorOTHER_GOV
University of Turku
CollaboratorOTHER
University of Helsinki
CollaboratorOTHER
Helsinki University Central Hospital
CollaboratorOTHER

Study design

Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
TREATMENT
Masking
NONE

Eligibility

Sex/Gender
ALL
Age
18 Years to 40 Years
Healthy volunteers
Yes

Inclusion criteria

* written informed consent * 18-40 years of age * good health * systolic blood pressure of at least 115 mmHg * all screening laboratory results (P-Krea, Pt-GFReEPI, P-Na, P-K, P-ALAT, P-AFOS, P-GT, B-PVK+T) acceptable; minor deviations from reference ranges are acceptable at the discretion of a physician-scientist with the exceptions of Pt-GFReEPI which must be at or above the reference limit and P-K which must be at or below the higher reference limit (Reference limits: Tyks Laboratories, Turku University Hospital) * regarding female subjects, a negative pregnancy test (S-HCG-O) before the study, and the use of a highly effective contraceptive method (e.g. copper intrauterine device, bilateral tubal occlusion, vasectomised partner, or abstinence from heterosexual intercourse), according to CTFG Recommendations related to contraception and pregnancy testing in clinical trials, are required

Exclusion criteria

* inability to provide written informed consent in Finnish * remarkable illness * confirmed or reasonably suspected allergy to cephalexin, amoxicillin, benzylpenicillin, phenoxymethylpenicillin, piperacillin, cefaclor, or cefamandole * confirmed or reasonably suspected severe delayed allergic reaction to any beta-lactam antibiotic * underweight (BMI less than 18.5 kg/m2) * obesity (BMI greater than 30 kg/m2) * smoking * regular medication, including hormonal contraception in the form of pills, intrauterine device, subdermal implant etc. * current or planned pregnancy, and breastfeeding * less than three months elapsed since a prior clinical trial * less than three months elapsed since donating blood

Design outcomes

Primary

MeasureTime frame
Plasma concentrations of cephalexin over time, the cumulative urinary excretion of cephalexin, and the pharmacokinetic parameters derived from these measurements following simultaneous or staggered ingestion of losartanup to 8 hours after ingestion of cephalexin on three consecutive days separated by at least one-week intervals

Secondary

MeasureTime frameDescription
Plasma concentrations of losartan and losartan carboxylic acid over time, the cumulative urinary excretion of losartan and losartan carboxylic acid, and the pharmacokinetic parameters derived from these measurementsup to 11 hours after ingestion of losartan or water on three consecutive days separated by at least one-week intervalsfollowing simultaneous and staggered ingestion of cephalexin

Countries

Finland

Contacts

CONTACTAleksi Tornio, M.D., Ph.D.
aleksi.tornio@utu.fi+358504765715
PRINCIPAL_INVESTIGATORAleksi Tornio, M.D., Ph.D.

Unit of Clinical Pharmacology, Turku University Hospital

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Mar 26, 2026