isoxsuprine isoxsuprine isoxsuprine (used as isoxsuprine hydrochloride) is a drug used as a vasodilator in humans (under the trade name duvadilan) and equines. isoxsuprine is a β2 adrenoreceptor agonist that causes direct relaxation of uterine and vascular smooth muscle via β2 receptors. isoxsuprineclinical datapronunciation/aɪˈsɒksjʊpriːn/ trade namesduvadilan, vasodilanmedlineplusa682831routes ofadministrationoral (tablets)atc codec04aa01 (who) legal statuslegal status in general: ℞ (prescription only) pharmacokinetic databioavailability~100% (humans), 2.2% (horses; oral)onset of action1 hourelimination half-life<3 hours (horses)excretionmainly renalidentifiers iupac name 4-phenol cas number395-28-8pubchem cid3783drugbankdb08941chemspider3651 yuniir15ui3245nkeggd08092 ychemblchembl1197051 ncomptox dashboard (epa)dtxsid9023178 echa infocard100.006.272 chemical and physical dataformulac18h23no3molar mass301.386 g·mol−13d model (jsmol)interactive image smiles o(c1ccccc1)cc(nc(c)c(o)c2ccc(o)cc2)c inchi inchi=1s/c18h23no3/c1-13(12-22-17-6-4-3-5-7-17)19-14(2)18(21)15-8-10-16(20)11-9-15/h3-11,13-14,18-21h,12h2,1-2h3 ykey:bmukktuhudjsnz-uhfffaoysa-n y use in humans isoxsuprine is used in humans for treatment of premature labor, i.e. a tocolytic, and as a vasodilator for the treatment of cerebral vascular insufficiency, raynaud's phenomenon, and other conditions. isoxsuprine may increase the heart rate, cause changes in blood pressure, and irritate the gi tract. it should therefore be used with caution if combined with other drugs that affect blood pressure, such as sedatives and anesthetic drugs. in horses isoxsuprine is most commonly used to treat hoof-related problems in the horse, most commonly for laminitis and navicular disease, as its effects as a vasodilator are thought to increase circulation within the hoof to help counteract the problems associated with these conditions. isoxsuprine is given orally, and many horses find the pills quite palatable. isoxsuprine is a prohibited class b drug in fei-regulated competition, and is often prohibited by other equine associations. it may be detected in the urine for several weeks or months following administration. it is therefore important to check the drug-rules within an animal's given competitive organization, before administering the drug. because it is a vasodilator, it should not be used in horses that are bleeding, or in mares following foaling.