From the Guidelines
Terlipressin causes more vasoconstriction in the mesenteric vessels compared to midodrine. Terlipressin is a vasopressin analog that acts primarily on V1 receptors found abundantly in the splanchnic circulation, producing potent mesenteric vasoconstriction 1. It is typically administered at doses of 1-2 mg intravenously every 4-6 hours. Midodrine, an alpha-1 adrenergic agonist, also causes vasoconstriction but has less selective effects on the mesenteric vessels. Midodrine is usually given orally at doses of 5-10 mg three times daily. The difference in vasoconstrictor potency in the mesenteric circulation explains why terlipressin is often preferred in conditions like hepatorenal syndrome and variceal bleeding, where reducing portal pressure through mesenteric vasoconstriction is crucial. Terlipressin's stronger effect on reducing portal pressure and increasing effective arterial blood volume makes it more effective for these specific conditions, though it carries risks of ischemic complications due to its potent vasoconstrictive properties 1.
Some key points to consider when using terlipressin include:
- It is contraindicated in patients with hypoxemia and in patients with ongoing coronary, peripheral, or mesenteric ischemia 1
- It should be used with caution in patients with acute-on-chronic liver failure grade 3 1
- The benefits may not outweigh the risks in patients with serum creatinine >5 mg/dL and in patients listed for transplantation with a Model for End-stage Liver Disease ≥35 1
- Terlipressin treatment does not require intensive care unit monitoring and can be administered intravenously through a peripheral line 1
In contrast, midodrine is a peripheral selective α1-adrenergic agonist that exerts a pressor effect through both arteriolar constriction and venoconstriction of the capacitance vessels, but its effects on the mesenteric vessels are less potent compared to terlipressin 1.
Overall, the choice between terlipressin and midodrine depends on the specific clinical context and the patient's individual needs, with terlipressin being the preferred option for conditions like hepatorenal syndrome and variceal bleeding due to its potent vasoconstrictive effects on the mesenteric vessels.
From the Research
Vasoconstriction in Mesentery Vessels
- Midodrine and terlipressin are both used to treat various medical conditions, but their effects on vasoconstriction in mesentery vessels differ.
- Terlipressin has been shown to have direct vasoconstrictor properties, causing a rapid and dose-dependent contraction of rat aortas and human uterine arteries 2.
- The study also found that terlipressin induced a saturable and dose-dependent vasoconstriction of coronary arteries, which was reversible and antagonized by selective V1a antagonists 2.
- Another study found that terlipressin elevated blood pressure and inhibited intestinal epithelial apoptosis and macrophage M1 polarization via the PI3K/Akt pathway in a model of acute mesenteric ischemia 3.
- There is no direct comparison between midodrine and terlipressin in terms of vasoconstriction in mesentery vessels in the provided studies.
- However, based on the available evidence, terlipressin appears to have a more significant vasoconstrictive effect on mesentery vessels due to its direct vasoconstrictor properties and its ability to elevate blood pressure and inhibit intestinal epithelial apoptosis and macrophage M1 polarization 3, 2.
Comparison of Midodrine and Terlipressin
- Midodrine is an alpha-adrenergic agonist used to treat orthostatic hypotension, while terlipressin is a vasopressin analog used to treat hepatorenal syndrome and other conditions.
- The provided studies do not directly compare the effects of midodrine and terlipressin on vasoconstriction in mesentery vessels.
- However, the studies suggest that terlipressin has a more significant vasoconstrictive effect on mesentery vessels due to its direct vasoconstrictor properties and its ability to elevate blood pressure and inhibit intestinal epithelial apoptosis and macrophage M1 polarization 3, 2.
- Further studies are needed to directly compare the effects of midodrine and terlipressin on vasoconstriction in mesentery vessels.