Ornipressin
A V1-selective form of vasopressin used for decades to reduce bleeding in surgery and tested in hepatorenal syndrome
Ornipressin is vasopressin with ornithine in place of the eighth amino acid. The change makes it act almost only on V1 receptors, which tighten blood vessels, with little of vasopressin's water-retaining effect. From the 1970s it was injected with local anaesthetics to reduce bleeding in ear, nose, plastic, burn and gynaecological surgery, and in the 1990s it was given by infusion to reverse hepatorenal syndrome, where it worked but caused ischaemic complications. It has no US approval, and no product containing it appears in the EU's current medicines data.
Used in human trials: 1-2 IU/h, Continuous infusion, started at 1 IU/h, Intravenous (Study: hypotension under combined general/epidural anaesthesia (ran...) Details ↓
Recommended Dosing
Used in human trials
No manufacturer dose exists for this use: these are amounts given in published trials, not recommendations.
What is it?
Ornipressin is a synthetic analogue of vasopressin, the pituitary hormone that conserves water and constricts blood vessels. Swapping the arginine at position 8 for ornithine gives a peptide that acts mainly on V1 receptors on blood vessel muscle. In a 262-operation series it showed no measurable antidiuretic effect, so its use has always been as a vasoconstrictor. Its potency is given in international units; one unit is about 2.8 micrograms (PMID 9113189).
Its longest use was local. Surgeons mixed it with lidocaine and injected it into the operating field to reduce bleeding in nose, ear, plastic, burn, spine and gynaecological operations, often as an alternative to adrenaline. Trials from the 1970s and 1980s found it about as effective as adrenaline in some settings and less effective in middle ear surgery. Its appeal was that it did not raise heart rate or trigger arrhythmias with inhaled anaesthetics the way adrenaline can.
It is not free of cardiovascular effects. Once absorbed it constricts vessels throughout the body: blood pressure, especially diastolic, can rise, heart rate falls, cardiac output can drop, and in guinea pig hearts it narrowed the coronary arteries. Under some anaesthetic techniques blood pressure rose sharply after infiltration. Those effects are the same mechanism that made it useful when given by vein.
In the 1990s hepatologists used intravenous ornipressin for hepatorenal syndrome, the kidney failure of advanced cirrhosis, which is driven by widened gut blood vessels and a squeezed renal circulation. A four-hour infusion improved kidney blood flow and filtration; 15 days with albumin normalised creatinine; and with dopamine it reversed type 1 hepatorenal syndrome in four of seven patients. But intestinal ischaemia and arrhythmia stopped treatment in several patients, and terlipressin, which has its own entry, became the vasoconstrictor used for this condition.
Its present status is unclear from public records. Drugs@FDA holds no record, and EMA's Article 57 data, which list every human medicine authorised in the EU and EEA, contain no ornipressin product, while they do list felypressin and terlipressin. A 2015 trial from Kenya still used ornipressin during fibroid surgery. We did not search other countries' registers, so this page does not say where, if anywhere, it is sold today.
Mechanism of Action
Ornipressin activates vasopressin V1 receptors on vascular smooth muscle, constricting small vessels locally where it is injected and throughout the body once it reaches the circulation.
Local vasoconstriction
Injected into tissue with a local anaesthetic it narrows small vessels, reducing bleeding and, in rats, deepening and lengthening the nerve block.
Systemic pressure
By vein it raises vascular resistance and blood pressure, which restored pressure during epidural-related hypotension.
Kidney perfusion in cirrhosis
Constricting the dilated gut circulation raised arterial pressure, damped renin and sympathetic activity and let kidney blood flow recover.
Heart and gut effects
It slows the heart, can lower cardiac output and constricts coronary and splanchnic vessels, the source of its ischaemic complications.
Published Research
These are studies of ornipressin read from their PubMed abstracts: randomised and observational studies of local infiltration in surgery, infusion trials for low blood pressure under anaesthesia and for hepatorenal syndrome, a volunteer skin study, a bronchoscopy series, and two animal studies. Many date from the 1970s to 1990s.
Restores blood pressure under combined anaesthesia
Sixty patients having bowel surgery under combined general and epidural anaesthesia were studied; those whose pressure fell by 20% were randomised, double-blind, to dopamine, norepinephrine or ornipressin. Ornipressin brought pressure back in about 8 minutes, as fast as norepinephrine (7) and faster than dopamine (11), mostly at the second infusion step in the study's schedule (11 of 15 patients). It caused no ST-segment changes, but gastric tonometry showed constriction of the gut circulation.
Reverses hepatorenal syndrome with albumin, at a cost
Sixteen patients with cirrhosis and hepatorenal syndrome received ornipressin with albumin volume expansion for 3 or 15 days (eight each). Three days normalised the overactive renin and sympathetic systems but improved kidney function only slightly; 15 days normalised serum creatinine and raised kidney blood flow and filtration. Three of the eight patients on the 15-day course had to stop because of ischaemic complications.
Longer courses with dopamine in type 1 hepatorenal syndrome
Seven patients with type 1 hepatorenal syndrome, whose kidneys kept failing despite albumin and low-dose dopamine, were given continuous intravenous ornipressin with dopamine. The syndrome reversed in four after 5 to 27 days. One patient stopped after 15 days with intestinal ischaemia and another, on retreatment, after 2 hours with ventricular tachyarrhythmia; three of the seven survived, two of them via liver transplantation.
A four-hour infusion improves kidney function in cirrhosis
In 11 patients with decompensated cirrhosis and worsening kidney function, a four-hour ornipressin infusion raised inulin clearance by 65%, kidney blood flow by 44% and sodium excretion more than threefold. Systemic vascular resistance rose 60% while kidney vascular resistance fell 27%, and the raised noradrenaline and renin levels roughly halved, reversing the hyperdynamic circulation typical of cirrhosis.
Finding the right strength for skin infiltration
Thirty volunteers had small intradermal injections of five strengths of ornipressin into skin whose blood flow had been raised with histamine. Constriction began at the weakest strength and was strongest at the middle two; the strongest solution was less effective and always left a red centre. The authors suggested a low strength for skin haemostasis to reduce the total amount and side effects.
As good as adrenaline for haemostasis in children, with a steadier heart
In a double-blind randomised trial in 30 children having surgery for protruding ears under enflurane, blood loss was similar with local ornipressin (14.3 mL) and adrenaline (11.7 mL). Heart rate fell steadily with ornipressin, from 134 to 116 beats per minute, but rose with adrenaline, which also raised systolic pressure; the authors noted that adrenaline's rises predispose to ventricular arrhythmia.
Weaker than adrenaline in middle ear surgery
In a double-blind comparison during middle ear operations, local adrenaline gave significantly better haemostasis than ornithine-8-vasopressin. Adrenaline raised systolic pressure and pulse rate, whereas ornipressin markedly raised diastolic pressure and slowed the pulse; transient ECG changes occurred in 6% to 17% of patients across the groups.
A high strength in nose surgery depends on the anaesthetic
In 127 patients having nasal surgery, a concentrated ornipressin solution in lidocaine gave good haemostasis in 86.5% under halothane or enflurane anaesthesia, with steady blood pressure and heart rate. Under diazepam-fentanyl anaesthesia blood pressure rose after infiltration and haemostasis was good in only about 60%, so the authors advised against that strength in patients with unstable blood pressure.
Local vasoconstriction in 262 ENT operations
Infiltrated with lidocaine in 262 ear, nose and throat operations, ornipressin gave good vasoconstriction in 85% to 90% under inhalational anaesthesia and 60% to 83% under diazepam-fentanyl. Under inhaled anaesthesia systolic pressure dipped about 10% and diastolic rose 6%; under diazepam-fentanyl both rose by about a quarter. Sodium, potassium and osmolality were unchanged at 24 hours, showing no antidiuretic effect.
Less bleeding when burn wounds in children are excised
In a paediatric burn unit, ornipressin infiltrated under the eschar before excision, and later into donor sites, was used in 145 and then 25 children. Bleeding fell sharply, grafts of up to 20% of body surface could be done in one operation with 95% to 100% take, heart rate did not change and arterial pressure rose 5% to 10%, with no general or local complications recorded.
Halves transfusions in childhood spine surgery with haemodilution
In 67 children having spinal surgery, those who had deliberate haemodilution plus local ornipressin lost about 151 mL of blood per vertebra against 344 mL in those who had neither, and needed a mean of three units of transfused blood instead of seven. Because the two measures were combined, the share due to ornipressin cannot be separated.
Bloodless field for laparoscopic gynaecological surgery
Dilute ornipressin injected locally in 60 patients having pelviscopic surgery, including fibroid removal, salpingotomy for tubal pregnancy and ovarian cystectomy, produced local ischaemia that made the procedures easier. The authors reported that it was well tolerated with no side effects observed; there was no comparison group.
Background haemostat in a Kenyan myomectomy trial
In this randomised double-blind trial from Nairobi, all 34 women having open myomectomy received ornipressin diluted in saline during surgery, and half also received intravenous tranexamic acid. Median blood loss was 398 mL with ornipressin alone and 251 mL with the combination, a difference that was not significant. The trial tested tranexamic acid; it shows ornipressin still in surgical use in 2015 rather than testing ornipressin itself.
Instilled into the airway for bronchoscopy bleeding
In a retrospective review of 2,592 bronchoscopies, 110 caused bleeding needing treatment. In 15 patients given ornipressin through the bronchoscope, heart rate and blood pressure did not change, while in 15 given terlipressin heart rate rose and pressure fell slightly. No patient died of bleeding or needed further intervention; efficacy was not compared directly.
Worrying haemodynamic effects in maxillofacial surgery
Invasive haemodynamic monitoring in five patients given ornipressin for oral and maxillofacial surgery under general anaesthesia showed marked rises in blood pressure and peripheral vascular resistance with a fall in cardiac output. The authors noted that it does not provoke arrhythmias with inhaled anaesthetics but that these effects were a concern.
Depresses the heart mainly by narrowing coronary arteries
In isolated guinea pig hearts, ornipressin reduced coronary flow in a concentration-dependent way when perfused at constant pressure, slowing the heart, lowering ventricular pressure and raising oxygen extraction. At constant flow, its direct effect on the heart muscle was small. The authors concluded that its cardiac depression is mostly secondary to coronary vasoconstriction.
Speeds and deepens lidocaine nerve block in rats
In anaesthetised rats, measuring conduction in a branch of the sciatic nerve, adding ornipressin to lidocaine shortened the onset of the block and improved its depth and duration, whereas adding adrenaline only lengthened it. The authors offered ornipressin as an alternative where adrenaline is unwanted.
Dosing Data
Ornipressin has no current US approval and no product in the EU's medicines data. These amounts come from published human studies, as stated in their abstracts; each was given by clinicians under monitoring during surgery or intensive care.
Educational information, not medical advice. Each dose above is tagged with its source: an approved label, a published human study, animal data, or amounts reported by users. None is a recommendation for you. An unapproved compound has no established safe or effective human dose, and products sold for “research use only” are not made or tested for people. Talk to a doctor before acting on anything on this site, including before you start, stop or change any medicine or dose. Full medical disclaimer.
What a Buyer Needs to Know
What is sold, how it is mixed, stored and taken, and what is known about its safety, quality and legal status. Each part names its source. Where we have none, it says unknown.
What is sold
Unknown: we hold no label and no published test that says what forms or vial sizes Ornipressin is sold in. A vial's own label is a seller's claim, not a source.
Mixing a vial: a worked example
No worked example: none of the doses on this page is a fixed amount in mg or mcg injected under the skin or into a muscle (the routes given are: endobronchial, intravenous, local infiltration). There is no home-mixing step to show. The reconstitution calculator does the arithmetic for any vial.
Source: the route and amount of each dose row in Dosing Data below.
Storage before and after mixing
Unknown: no label or published stability study on file says how to store Ornipressin, before or after mixing. The mixing guide sets out the general rules, with their sources: keep a mixed vial in the fridge, and use it promptly, as the bacteriostatic water label says of any drug dissolved in it. The 28 days often quoted is the limit for an opened multiple-dose vial from a manufacturer, an outer limit set for sterility, not a time a mixed solution has been shown to keep. Nobody has published how long Ornipressin stays intact once mixed.
How it is taken
As it was given in human studies: Intravenous (Continuous infusion, started at 1 IU/h; Study: hypotension under combined general/epidural anaesthesia (randomised)); Local infiltration (Single infiltration (5 IU per 10 mL of 1% lidocaine); Study: local vasoconstriction in 262 ENT operations); Endobronchial (Single instillation through the bronchoscope; Study: bronchoscopy-related bleeding (retrospective, 15 patients)).
For injection technique, sites and needle disposal, see the mixing guide.
Source: Used in human trials: the route and frequency of each row in Dosing Data below.
What to expect, and when
How long it stays in the body: not established by a measurement cited on this entry.
How long the doses were given: Study: hypotension under combined general/epidural anaesthesia (randomised): Until blood pressure recovered; 2 IU/h worked in 11 of 15; Study: type 1 hepatorenal syndrome, with dopamine (7 patients): 5 to 27 days, until creatinine clearance passed 40 mL/min or adverse events; Study: functional renal failure in decompensated cirrhosis (11 patients): 4 hours.
When effects appear: unknown; no source on this page gives a time to effect for Ornipressin. Results reported in the studies are under Published Research.
Source: Used in human trials, the duration of each row in Dosing Data below.
Side effects, and when to stop or get help
From the Side Effects section: Ischaemic complications stopped a 15-day course in 3 of 8 hepatorenal patients (PMID 9425914); Intestinal ischaemia and ventricular tachyarrhythmia during infusion for type 1 hepatorenal syndrome (PMID 10498636); Constriction of the gut circulation on gastric tonometry at low infusion rates (PMID 10825311); Rises in blood pressure and vascular resistance with reduced cardiac output after infiltration (PMIDs 2041535, 6612181); Slowing of the heart rate (PMIDs 7124315, 855911). Full list and cautions ↓
When to stop or get help: unknown; no label or trial on file sets rules for stopping Ornipressin. Treat a severe or unexpected reaction as a reason to stop and see a doctor.
Source: the Side Effects section below (“Side effects in the studies follow from vasoconstriction, locally and once the drug reaches the circulation”).
Interactions
Unknown: a PubMed search for human interaction studies of Ornipressin (reviewed 2026-10-28) found none. Unknown is not the same as safe to combine.
Every peptide's record, with its source: the interaction matrix.
Checking what you bought
Unknown: no published independent test of Ornipressin products is in our lab-results database yet, so how products sold under this name measure up is not known.
To read a certificate of analysis, paste it into the COA decoder; it checks the measured mass against Ornipressin's expected mass, 1,042.2 Da, from this entry's molecular data. Trust & Verification explains what independent testing can and cannot show.
Legal status
US: Not FDA Approved (Not FDA-approved: Drugs@FDA (openFDA) returns no record). Sport: Unsettled (S0 may apply).
Country by country ↓ · Regulatory tracker
Source: this entry's approval status and the WADA Prohibited List, as in Legal Status below.
Side Effects & Contraindications
Reported Side Effects
Side effects in the studies follow from vasoconstriction, locally and once the drug reaches the circulation.
Contraindications & Cautions
No current label was found; the studies point to these cautions.
Legal Status
Ornipressin has no US approval, and no product containing it appears in the EU's current medicines data; we did not check other countries' registers.
Frequently Asked Questions
?What is ornipressin?
A synthetic vasopressin analogue with ornithine at position 8. It acts mainly on V1 receptors to constrict blood vessels, with little antidiuretic effect.
?What was it used for?
Mainly as a local vasoconstrictor mixed with a local anaesthetic to reduce bleeding in surgery, and in studies by infusion for low blood pressure under anaesthesia and for hepatorenal syndrome.
?Is it better than adrenaline for surgical bleeding?
Results were mixed: as effective in children's ear surgery, less effective in middle ear surgery. It does not speed the heart like adrenaline, but it can raise diastolic pressure and slow the heart.
?Why is terlipressin used for hepatorenal syndrome instead?
Ornipressin did reverse hepatorenal syndrome in small studies, but ischaemic complications and arrhythmias stopped treatment in several patients. Terlipressin, covered on its own entry, became the standard vasoconstrictor.
?Is ornipressin approved?
Not in the US, and no product containing it appears in the EU's current medicines data. We did not verify its status in other countries.
?How is it dosed?
In international units. Studies infused 1 to 6 IU per hour by vein or infiltrated a few units locally; those were monitored hospital uses, not recommendations.
References
- [other] PubChem CID 14257660, Ornipressin: formula C45H63N13O12S2, molecular weight 1042.2. Read October 28, 2026. https://pubchem.ncbi.nlm.nih.gov/compound/14257660
- [clinical-trial] De Kock M, et al. "Ornipressin (Por 8): An efficient alternative to counteract hypotension during combined general/epidural anesthesia." Anesth Analg, 2000;90(6):1301-7. PMID: 10825311.
- [clinical-trial] Guevara M, et al. "Reversibility of hepatorenal syndrome by prolonged administration of ornipressin and plasma volume expansion." Hepatology, 1998;27(1):35-41. PMID: 9425914.
- [pubmed] Gülberg V, et al. "Long-term therapy and retreatment of hepatorenal syndrome type 1 with ornipressin and dopamine." Hepatology, 1999;30(4):870-5. PMID: 10498636.
- [pubmed] Lenz K, et al. "Ornipressin in the treatment of functional renal failure in decompensated liver cirrhosis. Effects on renal hemodynamics and atrial natriuretic factor." Gastroenterology, 1991;101(4):1060-7. PMID: 1832407.
- [pubmed] Fruhstorfer H, et al. "Dose-response relation of ornipressin with regard to vasoconstriction in human skin." Br J Anaesth, 1994;73(2):220-4. PMID: 7917739.
- [clinical-trial] Sharkey AJ, et al. "A comparative study of the haemostatic properties and cardiovascular effects of adrenaline and ornipressin in children using enflurane anaesthesia." Acta Anaesthesiol Scand, 1982;26(4):368-70. PMID: 7124315.
- [clinical-trial] Saarnivaara L, et al. "Comparison of the haemostatic and cardiovascular effects of adrenaline and ornithine-8-vasopressin (POR 8) in middle ear operations." Anaesthesist, 1977;26(3):144-7. PMID: 855911.
- [clinical-trial] Sigg O, et al. "Ornipressin as vasoconstrictor in rhinosurgery." Rhinology, 1983;21(2):159-64. PMID: 6612181.
- [pubmed] Hirlinger WK, et al. "[POR 8 (ornipressin). Local vasoconstrictive effect and hemodynamic activity during surgery in ENT clinics]." Anaesthesist, 1984;33(3):149-53. PMID: 6721128.
- [pubmed] De Mey A, et al. "Use of POR-8 in the management of burned children." Acta Anaesthesiol Belg, 1985;36(3):189-93. PMID: 3904301.
- [pubmed] Bernière J, et al. "[Value of deliberate normovolemic hemodilution associated with a capillary vasoconstrictor, ornipressin, in surgery of the spine]." Ann Fr Anesth Reanim, 1982;1(4):419-23. PMID: 7171139.
- [pubmed] Semm K, et al. "Local infiltration of ornithine 8-vasopressin (POR 8) as a vasoconstrictive agent in surgical pelviscopy (applied to myoma enucleation, salpingotomy in cases of tubal pregnancy and peripheral salpingostomy)." Endoscopy, 1988;20(6):298-304. PMID: 3229389.
- [clinical-trial] Ngichabe S, et al. "Intravenous tranexamic acid as an adjunct haemostat to ornipressin during open myomectomy. A randomized double blind placebo controlled trial." Ann Surg Innov Res, 2015;9:10. PMID: 26568770.
- [pubmed] Tüller C, et al. "Hemodynamic effects of endobronchial application of ornipressin versus terlipressin." Respiration, 2004;71(4):397-401. PMID: 15316215.
- [pubmed] Chiarini L, et al. "[The adverse effects induced by ornipressin during oral and maxillofacial surgical interventions under general anesthesia]." Minerva Stomatol, 1991;40(1-2):77-9. PMID: 2041535.
- [pubmed] Graf BM, et al. "Synthetic 8-ornithine-vasopressin, a clinically used vasoconstrictor, causes cardiac effects mainly via changes in coronary flow." Acta Anaesthesiol Scand, 1997;41(3):414-21. PMID: 9113189.
- [pubmed] Prokopiou AA, et al. "The effects of ornipressin and adrenaline on lignocaine nerve blocks." Acta Anaesthesiol Scand, 1986;30(8):647-50. PMID: 3811808.
Sources & Citations
Every study on this page was read from its PubMed record on October 29, 2026. Status comes from Drugs@FDA (openFDA) and EMA's Article 57 product data, read the same day. Grey Peptides sells nothing and links to no vendor.
Medical Disclaimer: This content is for educational and informational purposes only. It is not medical advice, and nothing here is an instruction to obtain or use any compound. Talk to a licensed clinician about your own situation.