Isoprenaline was one of the first syntheticsympathomimeticamines and was the first selective β-adrenergic receptor agonist.[7][14] The medication was discovered in 1940[5] and was introduced for medical use in 1947.[15]
Historically, it was used to treat asthma via metered aerosol or nebulizing devices; it was also available in sublingual, oral, intravenous, and intramuscular formulations.[15] The U.S. National Asthma Education and Prevention Program Expert Panel recommends against its use as a nebulizer for acute bronchoconstriction.[18]
Available forms
Many formulations of isoprenaline appear to have been discontinued in the United States and many other countries.[4][1][2][3] In the United States, it remains available only as an injectablesolution.[4] It was previously also available in the United States as a solution, metered aerosol, powder, or disc for inhalation and as a tablet for sublingual and rectal administration, but these formulations were discontinued.[4]
Isoprenaline is minimally able to cross the blood–brain barrier and hence is a peripherally selective drug.[29][30] This is attributed to its high hydrophilicity.[29] Whereas the extraction of isoprenaline in a single passage of the brain circulation following intravenous injection in humans was 3.8%, the extraction of propranolol, which is a more lipophilic compound and is readily able to cross into the brain, was 63.0%.[29]
Isoprenaline is excreted primarily in the urine, as sulfateconjugates.[7][31][32][3] It is excreted 59 to 107% in urine and 12 to 27% in feces.[3] A majority of isoprenaline is excreted in urine in conjugated form, whereas 6.5 to 16.2% is excreted as unchanged isoprenaline and 2.6 to 11.4% is excreted as 3-O-methylisoprenaline and conjugates.[3][6]
Between 1963 and 1968 in England, Wales, Scotland, Ireland, Australia, and New Zealand there was an increase in deaths among people using isoprenaline to treat asthma. This was attributed to unintentional overdose: the inhalers produced in that area were dispensing five times the dosage dispensed by inhalers produced in the United States and Canada, where the deaths were not observed.[38][39]
The short duration of action and poor oral activity of isoprenaline led to the development of the much longer-acting and orally active orciprenaline (metaproterenol).[40][7]
Society and culture
Names
Isoprenaline is the major generic name of the drug and its INNTooltip International Nonproprietary Name, BANTooltip British Approved Name, and DCFTooltip Dénomination Commune Française.[35][1][36][2]Isoprenalina is its Italian generic name and its DCITTooltip Denominazione Comune Italiana.[1][2]Isoprenaline hydrochloride and isoprenaline sulfate are its BANMTooltip British Approved Name in the case of the hydrochloride and sulfatesalts, respectively.[1]Isoproterenol is another important synonym of the drug.[35][1][2]Isoproterenol hydrochloride is its USANTooltip United States Adopted Name and JANTooltip Japanese Accepted Name in the case of the hydrochloride salt and isoproterenol sulfate is its USAN and JAN in the case of the sulfate salt.[35][1][36][2] Other synonyms of the drug include isopropylnorepinephrine, isopropylnoradrenaline, and isopropydine.[35][1][36][2] It is additionally known by the former developmental code name WIN-5162.[1][2]
Isoprenaline has been marketed under many brand names worldwide.[1][2] These include Aleudrina, Asthpul, Iludrin, Iprenol, Isomenyl, Isuprel, Isoprenaline, Isoprenalina, Isoproterenol, Neo-Epinine, Neodrenal, Proternol, and Saventrine, among others.[1][2] It is also marketed as a combination drug with cromoglicic acid as Frenal Compositum, in combination with pronase as Isopal P, and in combination with atropine as Stmerin D.[2]
^Cohagan B, Brandis D (August 2022). "Torsade de Pointes". StatPearls. Treasure Island (FL): StatPearls Publishing. PMID29083738. NBK459388.
^Kusumoto FM, Schoenfeld MH, Barrett C, Edgerton JR, Ellenbogen KA, Gold MR, et al. (August 2019). "2018 ACC/AHA/HRS Guideline on the Evaluation and Management of Patients With Bradycardia and Cardiac Conduction Delay: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society". Circulation. 140 (8): e382–e482. doi:10.1161/CIR.0000000000000628. PMID30586772.
^ abcdOlesen J, Hougård K, Hertz M (1978). "Isoproterenol and propranolol: ability to cross the blood-brain barrier and effects on cerebral circulation in man". Stroke. 9 (4): 344–349. doi:10.1161/01.str.9.4.344. PMID209581. Mean extraction of isoproterenol in a single passage of the brain circulation was 3.8% and the calculated PS product was 2.0 ml/100g/min. The mean extraction of propranolol was 63.0% and the mean PS product 46.7 ml/100 g/min. [...] Passage of Isoproterenol and Propranolol Across Blood–Brain Barrier: No data are available in the literature concerning the ability of isoproterenol to cross the blood-brain barrier. From the hydrophilic nature of the molecule one might expect diffusion to be very slow, but the possibility of active uptake mechanisms still existed. The extraction of 3.8% found in the present study corresponds to that of sodium or other hydrophilic molecules.12 It is likely that a significant part of this extraction stems from areas known to be devoid of a blood-brain barrier. The extraction is clearly much smaller than that seen for amino acids and other substances that pass the barrier by facilitated diffusion.14
^Crystal GJ, Salem MR (October 2002). "Beta-adrenergic stimulation restores oxygen extraction reserve during acute normovolemic hemodilution". Anesth Analg. 95 (4): 851–857, table of contents. doi:10.1097/00000539-200210000-00011. PMID12351256. The lack of effect of blood-borne catecholamines, including isoproterenol, on cerebral blood flow has been attributed to their inability to cross the blood-brain barrier (26).
^Jalba MS (2008). "Three generations of ongoing controversies concerning the use of short acting beta-agonist therapy in asthma: a review". The Journal of Asthma. 45 (1): 9–18. doi:10.1080/02770900701495512. PMID18259990. S2CID31732029.
† References for all endogenous human TAAR1 ligands are provided at List of trace amines
‡ References for synthetic TAAR1 agonists can be found at TAAR1 or in the associated compound articles. For TAAR2 and TAAR5 agonists and inverse agonists, see TAAR for references.