What Is Felypressin? Definition and What Research Reports

Definition

Felypressin is a synthetic octapeptide analogue of vasopressin, the posterior-pituitary hormone also known as antidiuretic hormone. Structurally it is described as 2-phenylalanine-8-lysine vasopressin: phenylalanine occupies position 2 where vasopressin carries tyrosine, and lysine occupies position 8 where human vasopressin carries arginine. Unlike epinephrine or norepinephrine, felypressin is not a catecholamine and does not belong to the adrenergic amine family — it is a small disulfide-bridged peptide. In the published literature the term appears almost entirely in two settings: dental and oral-surgery anaesthesia research, where felypressin is the vasoconstrictor combined with the local anaesthetic prilocaine in certain cartridge formulations, and comparative pharmacology, where peptide-type vasoconstrictors are studied alongside catecholamine vasoconstrictors. This page is for educational purposes only and is not medical advice; consult a licensed physician before making any health decisions.

What Class of Molecule Is It?

Felypressin sits in the vasopressin analogue class — the same broad family that includes desmopressin, terlipressin and ornipressin. All are laboratory-modified versions of the native nonapeptide hormone, engineered by substituting individual amino acids to shift the balance between antidiuretic activity and vascular activity, or to alter how quickly the molecule is cleared. Because the parent hormone is produced in the hypothalamus and released from the posterior pituitary, felypressin is often introduced in textbooks and reviews as a “synthetic pituitary hormone derivative,” although the compound itself is made synthetically rather than extracted from tissue.

How it relates to vasopressin receptors

Vasopressin and its analogues are generally discussed in terms of two receptor groupings: V1-type receptors associated with vascular smooth muscle, and V2-type receptors associated with renal water handling. Felypressin is characterised in the pharmacology literature as a vasopressin analogue whose interest in dentistry lies in vascular rather than antidiuretic activity, and a review in Anesthesia Progress examined the cardiovascular effects of felypressin specifically in the context of local anaesthesia (PMID 17177590). Researchers in that literature have contrasted this peptide-receptor route with the adrenergic-receptor route used by epinephrine, since the two act through entirely different receptor systems.

Where the Term Comes From

The name follows the convention used for vasopressin derivatives, where the “-pressin” suffix marks the lineage from vasopressin. Felypressin entered clinical vocabulary through dental anaesthesia, where a vasoconstrictor is added to a local anaesthetic solution to slow the removal of the anaesthetic from the injection site. Prilocaine with felypressin became a recognised formulation internationally, and much of the research vocabulary around the term — “prilocaine-felypressin,” “felypressin-containing solution,” “non-catecholamine vasoconstrictor” — comes from that setting. A 2004 paper in Current Drug Targets: Immune, Endocrine and Metabolic Disorders, for example, used the term in exactly this paired form when it examined lidocaine-epinephrine and prilocaine-felypressin in relation to functions related to natural immunity in neutrophils and macrophages (PMID 15032623).

How the Term Is Used in Peptide Research

For readers coming from peptide science, felypressin is a useful reference point for several reasons:

• As an example of analogue design. It illustrates how substituting two residues on a native nonapeptide hormone produces a distinct pharmacological agent with a different application profile from the parent molecule.
• As a comparator in vasoconstrictor studies. Experimental work frequently sets a peptide vasoconstrictor against a catecholamine vasoconstrictor; a 2015 study in the Journal of Anesthesia compared the pressure effects of epinephrine and felypressin in one-kidney, one-clip (1K1C) hypertensive rats treated or not treated with atenolol (PMID 24962945).
• As a clinical-pharmacology term. Cardiovascular monitoring studies in dental settings have used the word to describe the vasoconstrictor variable under investigation, as in a 2012 Arquivos Brasileiros de Cardiologia report on blood pressure during dental procedures in hypertensive patients (PMID 22735869).

Terminology map

What the Published Literature Reports

The evidence base summarised here is narrow and clinical in orientation rather than exploratory. The 2006 Anesthesia Progress article addressed the cardiovascular effects of felypressin directly, framing the compound within local-anaesthesia pharmacology (PMID 17177590). In an animal model, researchers compared the pressure effects of epinephrine and felypressin in 1K1C hypertensive rats, including animals treated and not treated with the beta-blocker atenolol, which allowed the two vasoconstrictor mechanisms to be examined against a background of beta-adrenergic blockade (PMID 24962945). On the human side, a 2012 study reported that felypressin increased blood pressure during dental procedures in hypertensive patients (PMID 22735869).

A separate strand of work looked beyond haemodynamics. The 2004 immunology paper examined immunological modulation by lidocaine-epinephrine and prilocaine-felypressin on functions related to natural immunity in neutrophils and macrophages, placing local anaesthetic-vasoconstrictor combinations in the context of innate immune cell function rather than blood pressure (PMID 15032623). Taken together, the literature referenced on this page is descriptive of what has been measured; it is not a basis for any individual decision, and no dosing information is presented here because doses are outside the scope of a definitional entry.

Cardiovascular and Immune Findings: What Studies Report

Where felypressin is discussed in terms of unwanted or unintended effects, the recurring theme in the cited literature is cardiovascular. The 2012 clinical report described an increase in blood pressure during dental procedures in hypertensive patients when felypressin was involved (PMID 22735869), and the 2006 review was devoted to the cardiovascular effects of the compound (PMID 17177590). The rat study extended the question to whether concurrent atenolol treatment altered the pressure response relative to epinephrine (PMID 24962945). Outside the cardiovascular domain, the 2004 study is the reference point for effects on innate immune cell function, having assessed prilocaine-felypressin alongside lidocaine-epinephrine in neutrophils and macrophages (PMID 15032623).

Common Points of Confusion

1. Felypressin is not epinephrine. Both function as vasoconstrictor components in local anaesthetic solutions, but one is a peptide and the other a catecholamine; the 2015 rat study treated them as distinct comparators (PMID 24962945).
2. Felypressin is not desmopressin. Both are vasopressin analogues, but they were designed for different purposes and appear in different literatures.
3. It is a prescription pharmaceutical ingredient, not a research chemical. Where felypressin appears in formulations, those products are regulated medicines subject to national approval frameworks, and the studies cited here were conducted in clinical or laboratory settings.

Summary of the Entry

Felypressin is a synthetic, two-residue-substituted analogue of vasopressin, classed as a peptide vasoconstrictor and encountered chiefly in dental anaesthesia research paired with prilocaine. The published work cited above examined its cardiovascular effects (PMID 17177590), compared it with epinephrine in a hypertensive rat model (PMID 24962945), reported blood-pressure increases during dental procedures in hypertensive patients (PMID 22735869), and assessed prilocaine-felypressin in relation to neutrophil and macrophage function (PMID 15032623). This entry is definitional and does not describe how the compound is used.

References

• Immunological modulation by lidocaine-epinephrine and prilocaine-felypressin on the functions related to natural immunity in neutrophils and macrophages (Current Drug Targets. Immune, Endocrine and Metabolic Disorders, 2004)
• Cardiovascular effects of felypressin (Anesthesia Progress, 2006)
• Felypressin increases blood pressure during dental procedures in hypertensive patients (Arquivos Brasileiros de Cardiologia, 2012)
• Comparison of epinephrine and felypressin pressure effects in 1K1C hypertensive rats treated or not with atenolol (Journal of Anesthesia, 2015)