Serelaxin dosage in published studies and labels

These are the doses used for Serelaxin in FDA labelling and published clinical studies, reported as each source states them, one row per regimen. They describe what was studied or approved for a specific population. They are not a recommendation, and none of them is a dose for any individual.

Research and educational reference only. This is not medical advice, and no figure on this page is a dosing recommendation.

Last checked against primary sources: November 7, 2026

Studied regimens and sources

Serelaxin has no approved dosage; there is no serelaxin label on DailyMed. Its human dosing comes from the RELAX-AHF trials in people hospitalised for acute heart failure, which gave a 48-hour intravenous infusion of 30 mcg/kg per day. RELAX-AHF met one of its two dyspnoea endpoints, but the larger RELAX-AHF-2 trial did not reduce cardiovascular death at 180 days or worsening heart failure at 5 days.

Clinical Trial Evidence

Dosage evidence summary for Serelaxin
Human dosing established	Yes
Route	Intravenous
Frequency	Continuous intravenous infusion
Duration studied	48 hours, started within 16 hours of presentation
Evidence level	Clinical Trial Evidence
Last reviewed	2026-11-07

Research-reported dosing

Doses as studied, one row per regimen. Different trials used different regimens; they are listed separately rather than averaged.

Research-reported dosing for Serelaxin, one row per studied regimen
Study / context	Population	Dose	Route	Frequency	Duration	Outcome studied	Source
RELAX-AHF — Lancet 2013 (NCT00520806)Clinical trial · Randomised, double-blind, placebo-controlled trial	Adults hospitalised for acute heart failure with dyspnoea, congestion, raised natriuretic peptides, mild-to-moderate renal insufficiency and systolic blood pressure above 125 mm Hg (n=1,161)	30 mcg/kg per day, or placebo, with standard care	Intravenous	Continuous infusion	48 hours	Improved dyspnoea on the visual analogue scale (one primary endpoint) but not on the Likert scale (the other); no effect on cardiovascular death or readmission at 60 days; fewer deaths at day 180 was a prespecified additional endpoint	Serelaxin, recombinant human relaxin-2, for treatment of acute heart failure (RELAX-AHF): a randomised, placebo-controlled trial. Lancet. 2013.
RELAX-AHF-2 — NEJM 2019 (NCT01870778)Clinical trial · Event-driven, randomised, double-blind, placebo-controlled trial	Adults hospitalised for acute heart failure meeting the same criteria (6,545 analysed)	30 mcg/kg per day, or placebo, with standard care	Intravenous	Continuous infusion	48 hours	Both primary endpoints missed: cardiovascular death at 180 days 8.7% versus 8.9% (HR 0.98) and worsening heart failure at 5 days 6.9% versus 7.7% (HR 0.89); adverse events similar	Effects of Serelaxin in Patients with Acute Heart Failure. N Engl J Med. 2019.

Where sources disagree

Serelaxin is recombinant human relaxin-2. Its trial dose is weight-based and was given only as a 48-hour hospital infusion; no other route or schedule was tested in these trials.
The fewer deaths at day 180 reported in RELAX-AHF were an additional endpoint; in the larger RELAX-AHF-2 trial, cardiovascular and all-cause death at 180 days did not differ from placebo.