Why Combining Blood Pressure Drugs That Target the Same System May Not Work Better
Combining RAS inhibitors changed angiotensin peptide profiles in complex ways but did not consistently improve blood pressure beyond single-drug therapy in hypertensive rats.
Quick Facts
What This Study Found
Lisinopril produced the strongest antihypertensive effect; dual RAS blockade created complex angiotensin peptide profile changes but only modest additional blood pressure reduction in this low-RAS model.
Key Numbers
SHR (spontaneously hypertensive rats). Tested lisinopril, olmesartan, aliskiren, and dual combinations. Lisinopril and olmesartan increased Ang I and Ang 1-7. Lisinopril suppressed Ang II while olmesartan increased it. Aliskiren reduced Ang II and Ang 1-7.
How They Did This
Preclinical study in spontaneously hypertensive rats (SHR) measuring hemodynamics and circulating and tissue angiotensin peptide levels during single and dual RAS inhibitor treatment.
Why This Research Matters
Understanding why combined RAS blockade fails to improve outcomes despite better blood pressure control is critical for developing safer and more effective antihypertensive strategies.
The Bigger Picture
This research explains at the peptide level why the clinical strategy of dual RAS blockade — which seemed logical on paper — has failed in practice. The angiotensin peptide system is more complex than simply blocking more receptors.
What This Study Doesn't Tell Us
Animal study in spontaneously hypertensive rats, which may not fully replicate human RAS physiology. The low-RAS setting of SHR may limit applicability to high-RAS forms of hypertension.
Questions This Raises
- ?Would results differ in high-RAS models of hypertension where angiotensin levels are elevated?
- ?Could tissue-specific peptide changes explain the adverse outcomes seen in clinical dual RAS blockade trials?
Trust & Context
- Key Stat:
- Modest additional benefit Dual RAS blockade provided only small blood pressure improvements over single-agent lisinopril despite changing multiple angiotensin peptide levels
- Evidence Grade:
- Preclinical animal study providing mechanistic insight. While it explains clinical observations, direct translation to human treatment decisions requires caution.
- Study Age:
- Published in 2025, adding modern peptide profiling data to the long-standing question of dual RAS blockade efficacy.
- Original Title:
- Combined RAS Modulation: The Effect on Plasma and Tissue Angiotensin Peptide Levels.
- Published In:
- Physiological research, 74(Suppl 2), S205-S218 (2025)
- Authors:
- Paulis, L, Rajkovicova, R, Repova, K, Gubo, G, Barta, A, Poglitsch, M, Domenig, O, Andelova, N, Ferko, M, Pechanova, O, Simko, F
- Database ID:
- RPEP-12991
Evidence Hierarchy
Tests effects in animals (usually mice or rats), not humans.
What do these levels mean? →Frequently Asked Questions
Why do doctors not usually combine blood pressure drugs from the same class?
Clinical trials showed that combining RAS inhibitors (like ACE inhibitors with ARBs) did not improve patient outcomes and sometimes increased side effects like kidney problems and high potassium. This study helps explain why — the peptide changes are complex and unpredictable.
What is the renin-angiotensin system?
The RAS is a hormone system that regulates blood pressure and fluid balance. Angiotensin II is its main effector, causing blood vessels to constrict and raising blood pressure. Many common blood pressure drugs work by blocking different steps in this system.
Read More on RethinkPeptides
Cite This Study
https://rethinkpeptides.com/research/RPEP-12991APA
Paulis, L; Rajkovicova, R; Repova, K; Gubo, G; Barta, A; Poglitsch, M; Domenig, O; Andelova, N; Ferko, M; Pechanova, O; Simko, F. (2025). Combined RAS Modulation: The Effect on Plasma and Tissue Angiotensin Peptide Levels.. Physiological research, 74(Suppl 2), S205-S218.
MLA
Paulis, L, et al. "Combined RAS Modulation: The Effect on Plasma and Tissue Angiotensin Peptide Levels.." Physiological research, 2025.
RethinkPeptides
RethinkPeptides Research Database. "Combined RAS Modulation: The Effect on Plasma and Tissue Ang..." RPEP-12991. Retrieved from https://rethinkpeptides.com/research/paulis-2025-combined-ras-modulation-the
Access the Original Study
Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.
This study breakdown was produced by the RethinkPeptides research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.