Evidence Snapshot
What this grade covers
Applies to Ornipressin's direct human evidence: one randomized controlled trial in a defined surgical-anesthesia-hypotension context (PMID 10825311, N=60) plus three additional direct human case-series studies across two distinct clinical contexts — ENT local-vasoconstrictor use (PMID 6721128, N=262) and continuous-infusion hepatorenal-syndrome treatment (PMID 9425914 N=16; PMID 10498636 N=7). This is real, multi-context, directly-administered human evidence, including one genuine RCT — not an absence-of-evidence grade, and not downgraded merely because the hepatorenal-syndrome results were ultimately unfavorable on safety grounds (a well-documented safety failure is evidence, not its absence). The grade is capped at 'C' rather than higher because: the evidence is dated (1980s-1990s, no modern trial identified), sample sizes outside the RCT are small/single-center, the drug's main modern-relevant indication (HRS) was ultimately abandoned specifically for ischemic-safety reasons in its continuous-infusion form, and current-status information is genuinely unresolved rather than reassuring. This grade does not extend to or from AVP, Terlipressin, or any other vasopressin-analogue subject in this project, despite superficial V1-mechanistic similarity to Terlipressin specifically.
Regulatory Context
No current FDA approval or US marketing history was identified for Ornipressin. Historical marketing, where documented, was specific to Germany, Switzerland, New Zealand, and Australia. Its current regulatory or clinical-availability status in any jurisdiction was not established in this review.
Research Takeaway
Ornipressin (POR-8, 8-ornithine-vasopressin) is a synthetic vasopressin analogue substituting ornithine for arginine at position 8, pharmacologically characterized as a V1-receptor-selective vasoconstrictor with materially reduced antidiuretic (V2) activity relative to native AVP — directly confirmed by a clinical case series finding no antidiuretic effect at vasoconstrictor doses.
See all 6 evidence claims →Quick Summary
Ornipressin (POR-8) is a synthetic, V1-selective vasopressin analogue with real historical human clinical use as both a local surgical vasoconstrictor and a continuous-infusion treatment for hepatorenal syndrome. Its strongest evidence includes a randomized trial showing effective, fast blood-pressure restoration during surgery, and case series showing genuine hepatorenal-syndrome reversal — but its major limitation is a well-documented ischemic-complication risk with continuous infusion that led to its abandonment in that specific indication, superseded by terlipressin.
Mechanism & Research Overview
Ornipressin (POR-8) is a synthetic, V1-selective vasopressin analogue with real historical human clinical use as both a local surgical vasoconstrictor and a continuous-infusion treatment for hepatorenal syndrome. Its strongest evidence includes a randomized trial showing effective, fast blood-pressure restoration during surgery, and case series showing genuine hepatorenal-syndrome reversal — but its major limitation is a well-documented ischemic-complication risk with continuous infusion that led to its abandonment in that specific indication, superseded by terlipressin.
Evidence Claims
Individual scientific statements drawn from the sources cited below, each shown with the specific evidence boundary that statement does not establish.
Supported
Ornipressin (POR-8, 8-ornithine-vasopressin) is a synthetic vasopressin analogue substituting ornithine for arginine at position 8, pharmacologically characterized as a V1-receptor-selective vasoconstrictor with materially reduced antidiuretic (V2) activity relative to native AVP — directly confirmed by a clinical case series finding no antidiuretic effect at vasoconstrictor doses.
Supported
In a randomized controlled trial, low-dose ornipressin restored blood pressure during anesthesia-induced hypotension as effectively and about as quickly as norepinephrine, and faster than dopamine, without major ischemic complications or ECG changes at this specific low dose and short duration.
Does not establish
Evidence boundary: This short-duration, low-dose surgical-adjunct finding does not extend to or contradict the continuous-infusion hepatorenal-syndrome ischemic-complication findings below, which involve a different dose, duration, and clinical population.
Supported
Prolonged (continuous-infusion) ornipressin administration, combined with albumin, can reverse hepatorenal syndrome in cirrhotic patients, with the greatest renal-function improvement seen after 15 days versus 3 days of treatment in one case series.
Sources: Reversibility of hepatorenal syndrome by prolonged administration of ornipressin and plasma volume expansion; Long-term therapy and retreatment of hepatorenal syndrome type 1 with ornipressin and dopamine
Supported
Continuous-infusion ornipressin for hepatorenal syndrome carries a well-documented risk of ischemic complications (mesenteric, myocardial, and associated arrhythmias in some reports), directly stated as a caution by the researchers who studied it, and adverse events limited continued treatment in at least one case series.
Sources: Reversibility of hepatorenal syndrome by prolonged administration of ornipressin and plasma volume expansion; Long-term therapy and retreatment of hepatorenal syndrome type 1 with ornipressin and dopamine
Supported
Ornipressin's use for continuous-infusion hepatorenal-syndrome treatment has been widely abandoned specifically because of this ischemic-complication risk, superseded by terlipressin in that indication; this is distinct from, and must not be generalized to, its separate historical use as a short-acting local/regional surgical vasoconstrictor, whose current status was not established in this review.
Sources: Reversibility of hepatorenal syndrome by prolonged administration of ornipressin and plasma volume expansion; Long-term therapy and retreatment of hepatorenal syndrome type 1 with ornipressin and dopamine
Supported
No current national regulator approval, hospital formulary listing, or FDA marketing status for Ornipressin was identified in this review; its historical marketing footprint, where documented, was specific to Germany, Switzerland, New Zealand, and Australia, never the United States.
Safety & Evidence Limitations
Considerations reported in the sources cited on this page — not a complete list of every possible risk, and not medical advice.
Higher-Priority Safety Consideration
Mesenteric, myocardial ischemia and associated arrhythmias documented in the primary HRS literature itself; the specific, well-documented reason this use was abandoned.Safety Consideration
Measurable gastric intracellular PCO2 rise (splanchnic vasoconstriction) seen even in the short-duration, low-dose RCT that otherwise showed no major ischemic complications.Safety Consideration
Evidence is 1980s-1990s era; no modern trial identified; current clinical status is genuinely unresolved, not confirmed as either continued or fully discontinued.Safety Consideration
The documented abandonment is specific to continuous-infusion HRS treatment; it must not be stated as a global discontinuation across all historical indications without further evidence.
Research Areas Being Studied
Research areas discussed on this page reflect the Renal / Fluid-Balance Signaling category and the sources cited below.
Findings Reported in Studies
Educational summary only — reported in cited studies, not a claim of proven benefit.
- Ornipressin (Por 8): An efficient alternative to counteract hypotension during combined general/epidural anesthesia (2000):
- Long-term therapy and retreatment of hepatorenal syndrome type 1 with ornipressin and dopamine (1999):
- Reversibility of hepatorenal syndrome by prolonged administration of ornipressin and plasma volume expansion (1998):
- [POR 8 (ornipressin). Local vasoconstrictive effect and hemodynamic activity during surgery in ENT clinics] ():
Study Tables by Evidence Type
Human Studies & Clinical Data
| Title | Year | Population / Model | Dose / Duration / Finding | Safety Notes | Source |
|---|---|---|---|---|---|
| Ornipressin (Por 8): An efficient alternative to counteract hypotension during combined general/epidural anesthesia | 2000 | N=60 patients undergoing intestinal surgery, randomized double-blind to dopamine, norepinephrine, or ornipressin (1 IU/h starting dose) | Ornipressin restored blood pressure in 8±2 minutes (comparable to norepinephrine's 7±3 minutes, faster than dopamine's 11±3 minutes) without major ischemic side effects or ECG (S-T segment) changes at this low, short-duration surgical-adjunct dose. | Significantly increased intracellular gastric PCO2, indicating measurable splanchnic vasoconstriction even at this low dose — distinct from, and not contradicting, the continuous-infusion HRS ischemic-complication finding (different dose, duration, and clinical context). | |
| Long-term therapy and retreatment of hepatorenal syndrome type 1 with ornipressin and dopamine | 1999 | N=7 HRS type 1 patients, continuous ornipressin (6 IU/h) + dopamine after albumin/dopamine alone had failed | HRS reverted in 4/7 patients after 5-27 days. | Treatment was continued 'until creatinine clearance had increased... or adverse events prevented further treatment' — adverse events were a real, treatment-limiting factor in this cohort, consistent with the ischemic-complication pattern reported elsewhere in the HRS literature. | |
| Reversibility of hepatorenal syndrome by prolonged administration of ornipressin and plasma volume expansion | 1998 | N=16 cirrhotic HRS patients, ornipressin + albumin for 3 or 15 days (8 each) | 15-day treatment produced marked improvement in renal function (normalized creatinine, increased renal plasma flow/GFR); 3-day treatment normalized RAAS/sympathetic overactivity with only slight renal improvement. | The paper's own conclusion states this treatment 'should be used with great caution in clinical practice because of the risk of ischemic complications.' | |
| [POR 8 (ornipressin). Local vasoconstrictive effect and hemodynamic activity during surgery in ENT clinics] | N=262 ENT operations; POR-8 5 IU/10 mL 1% lidocaine as local infiltration vasoconstrictor | Good local vasoconstriction in 60-90% of cases depending on anesthesia type; hemodynamic effects varied by anesthetic technique (BP fell under inhalational anesthesia, rose under diazepam-fentanyl); no antidiuretic effect observed (V1-selectivity confirmation). |
Animal / Cell / Preclinical Data
| Title | Year | Population / Model | Dose / Duration / Finding | Safety Notes | Source |
|---|---|---|---|---|---|
| Synthetic 8-ornithine-vasopressin, a clinically used vasoconstrictor, causes cardiac effects mainly via changes in coronary flow | Isolated guinea pig heart (Langendorff technique, constant-flow vs constant-pressure perfusion) | Ornipressin's cardiac depressive effects are mediated mainly indirectly, via reduced myocardial perfusion from coronary vasoconstriction, not by a direct negative-inotropic action on cardiac tissue. |
Regulatory Documents & Official Trial Registries
No Regulatory Documents & Official Trial Registries Listed Yet
This section will be updated as sources are added.
Anecdotal Reported Patterns — Not Medical Advice
Anecdotal Reported Patterns — Not Medical Advice
Reported dosing patterns are included for educational context only. They are self-reported, unverified, not medical advice, and not instructions for human use. Community-submitted patterns are not yet available in this Phase 1 prototype; this section is a placeholder reserved for moderated, aggregated community data.
Lab Markers to Discuss With a Clinician
Educational topics only — not self-monitoring instructions.
FAQ
Disclaimer
Educational information only. This page summarizes published historical clinical research about Ornipressin and does not provide medical advice, an individualized treatment recommendation, or dosing instructions.
Educational use only. This content is provided for informational and research-summary purposes only. It is not medical advice, not a treatment recommendation, not a dosing guide, and not a substitute for care from a licensed medical professional. Nothing here is intended to diagnose, treat, cure, prevent, or mitigate disease. Reported dosing patterns, when shown elsewhere on the site, must be labeled either as Study / Trial Dosing or Anecdotal Reported Patterns — Not Medical Advice. Community reports are self-reported, unverified, and not scientific proof.
Community-reported experiences, once enabled, must be displayed only as moderated, anonymized, or aggregated data. They are anecdotal, self-reported, unverified, and should never be presented as proof of safety, efficacy, or expected results.
Content status: Published. Last updated .
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