Etilefrine is a cardiac stimulant used as an antihypotensive. Intravenous infusion of this compound increases cardiac output, stroke volume, venous return and blood pressure in man and experimental animals, suggesting stimulation of both α and β adrenergic receptors. However, in vitro studies indicate that etilefrine has a much higher affinity for β1 (cardiac) than for β2 adrenoreceptors. Intravenous etilefrine increases the pulse rate, cardiac output, stroke volume, central venous pressure and mean arterial pressure of healthy individuals. Marked falls in pulse rate, cardiac output, stroke volume and peripheral bloodflow, accompanied by rises in mean arterial pressure, occur when etilefrine is infused after administration of intravenous propranolol 2,5 mg. These findings indicate that etilefrine has both β1 and α1 adrenergic effects in man. The French Health Products Agency concluded that etilefrine and heptaminol have an unfavourable harm-benefit balance, and also placed restrictions on the use of midodrine.

Dopexamine hydrochloride is a synthetic catecholamine, structurally related to dopamine, with marked intrinsic agonist activity at beta 2-adrenoceptors, lesser agonist activity at dopamine DA1- and DA2-receptors and beta 1-adrenoceptors, and an inhibitory action on the neuronal catecholamine uptake mechanism. The drug is administered by intravenous infusion, and is characterized by a rapid onset and short duration of action. Dopexamine is being tested as a treatment for heart failure and sepsis.

Xamoterol (ICI 118,587) is a partial agonist of beta1-adrenoceptors. Xamoterol acts on the cardiac beta 1-adrenergic receptor, modifies the response of the heart to variations in sympathetic activity. At rest, it produces modest improvements in cardiac contractility, relaxation, and filling without increase in myocardial oxygen demand. The improvements are maintained during exercise although the attendant tachycardia is attenuated. The beneficial effects of xamoterol on both systolic and diastolic function suggested that it would be effective in patients with mild-to-moderate heart failure, and this was demonstrated in small placebo-controlled studies where effort tolerance and symptoms were improved. Xamoterol produced improvements in exercise capacity, clinical signs, symptoms and quality of life with a low incidence of adverse experiences. Xamoterol is effective as monotherapy in heart failure.

Gepefrine (Pressionorm and Wintonin) is an antihypotensive agent. It was used for therapy of orthostatic dysregulation. One hour after oral administration of 30 mg or 45 mg gepefrine the blood pressure increased significantly at rest and more markedly on standing and during the step test. Gepefrine led to a reduction in pathological orthostatic regulation during the early phase as well as to the prevention of subjective and objective signs of orthostatic adjustment disorder during the late phase. Patients with insufficient rise in blood pressure during the step test (80 watts) showed after gepefrine a distinct tendency towards normalisation and the regression of subjective states of exhaustion. Gepefrine caused on average no substantive alternations in heart rate during all phases of the investigation. Complications or side-effects due to the method or the medicament were not observed.

Norfenefrine or meta-octopamine, also known as 3,β-dihydroxyphenethylamine, is an adrenergic agent used as a sympathomimetic drug which is marketed in Europe, Japan, and Mexico. Along with its structural isomer p-octopamine and the tyramines, norfenefrine is a naturally occurring, endogenous trace amine and plays a role as a minor neurotransmitter in the brain. Norfenefrine controls blood pressure in acute hypotensive states eg pheochromocytomectomy, sympathectomy, poliomyelitis, spinal anesth, MI, septicemia, blood transfusion and drug reactions. Adjunct in treatment of cardiac arrest and hypotension.

Levosimendan (Simdax) is a novel intravenous agent that exerts inotropic effects through sensitization of myofilaments to calcium and vasodilator effects by binding to cardiac troponin C in a calcium-dependent manner. It also has a vasodilatory effect, by opening adenosine triphosphate (ATP)-sensitive potassium channels in vascular smooth muscle to cause smooth muscle relaxation. Unlike other calcium sensitizing compounds, the binding of levosimendan is highly dependent on the intracellular concentration of calcium, such that calcium sensitivity is enhanced only when the calcium level is elevated. Levosimendan is licensed for the treatment of decompensated heart failure in many countries but not in North America. This drug also passed phase III clinical trials for the prevention of low cardiac output syndrome in pediatric patients after open heart surgery.

Bucladesine is a cyclic nucleotide derivative which mimics the action of endogenous cAMP and is a phosphodiesterase inhibitor. The compound is used in a wide variety of research applications because it mimics cAMP and can induce normal physiological responses when added to cells in experimental conditions. cAMP is only able to elicit minimal responses in these situations. The neurite outgrowth instigated by bucladesine in cell cultures has been shown to be enhanced by nardosinone. Recently, the effect of bucladesine as a cAMP analog has been studied on the pentylenetetrazol-induced seizure in the wild-type mice. The data showed that bucladesine (300nM/mouse) reduced the seizure latency and threshold. In addition they found that combination of bucladesine and pentoxyfillin has additive effect on seizure latency and threshold. Bucladesine is more lipophilic than cAMP and in contrast to cAMP capable of penetrating cell membranes. Bucladesine interferes with different protein kinases which are normally activated by cAMP. Bucladesine has undergone in the past clinical developments as systemic treatment for cardioprotection and as topical treatment to improve wound healing. In Japan, a bucladesine ointment (Actosin® ointment; Daiichi Pharmaceutical Co., Ltd., Tokyo, Japan) was marketed to treat skin ulcers. Clinical studies have shown favourable effects on diabetic foot ulcers or decubitus, but the compound was later withdrawn despite good tolerability. One possible reason for the withdrawal may be the odour of the cream formulation which can be related to the hydrolytic cleavage in aqueous solutions resulting in release of butyric acid.

Angiotensin is a peptide hormone that causes vasoconstriction and a subsequent increase in blood pressure. It is part of the renin-angiotensin system, which is a major target for drugs that lower blood pressure. Angiotensin also stimulates the release of aldosterone, another hormone, from the adrenal cortex. Aldosterone promotes sodium retention in the distal nephron, in the kidney, which also drives blood pressure up. Angiotensin is an oligopeptide and is a hormone and a powerful dipsogen. Angiotensin I is derived from the precursor molecule angiotensinogen, a serum globulin produced in the liver. Angiotensin I is converted to angiotensin II (AII) through removal of two C-terminal residues by the enzyme angiotensin-converting enzyme (ACE), primarily through ACE within the lung (but also present in endothelial cells and kidney epithelial cells). ACE found in other tissues of the body has no physiological role (ACE has a high density in the lung, but activation here promotes no vasoconstriction, angiotensin II is below physiological levels of action). Angiotensin II acts as an endocrine, autocrine/paracrine, and intracrine hormone. Angiotensin II has prothrombotic potential through adhesion and aggregation of platelets and stimulation of PAI-1 and PAI-2. When cardiac cell growth is stimulated, a local (autocrine-paracrine) renin-angiotensin system is activated in the cardiac myocyte, which stimulates cardiac cell growth through protein kinase C. The same system can be activated in smooth muscle cells in conditions of hypertension, atherosclerosis, or endothelial damage. Angiotensin II is the most important Gq stimulator of the heart during hypertrophy, compared to endothelin-1 and α1 adrenoreceptors. Angiotensin II increases thirst sensation (dipsogen) through the subfornical organ of the brain, decreases the response of the baroreceptor reflex, and increases the desire for salt. It increases secretion of ADH in the posterior pituitary and secretion of ACTH in the anterior pituitary. It also potentiates the release of norepinephrine by direct action on postganglionic sympathetic fibers. Angiotensin II acts on the adrenal cortex, causing it to release aldosterone, a hormone that causes the kidneys to retain sodium and lose potassium. Elevated plasma angiotensin II levels are responsible for the elevated aldosterone levels present during the luteal phase of the menstrual cycle. Angiotensin II has a direct effect on the proximal tubules to increase Na+ reabsorption. It has a complex and variable effect on glomerular filtration and renal blood flow depending on the setting. Increases in systemic blood pressure will maintain renal perfusion pressure; however, constriction of the afferent and efferent glomerular arterioles will tend to restrict renal blood flow. The effect on the efferent arteriolar resistance is, however, markedly greater, in part due to its smaller basal diameter; this tends to increase glomerular capillary hydrostatic pressure and maintain glomerular filtration rate. A number of other mechanisms can affect renal blood flow and GFR. High concentrations of Angiotensin II can constrict the glomerular mesangium, reducing the area for glomerular filtration. Angiotensin II is a sensitizer to tubuloglomerular feedback, preventing an excessive rise in GFR. Angiotensin II causes the local release of prostaglandins, which, in turn, antagonize renal vasoconstriction. The net effect of these competing mechanisms on glomerular filtration will vary with the physiological and pharmacological environment. Angiotensin was independently isolated in Indianapolis and Argentina in the late 1930s (as 'angiotonin' and 'hypertensin', respectively) and subsequently characterised and synthesized by groups at the Cleveland Clinic and Ciba laboratories in Basel, Switzerland.

Angiotensinamide is octapeptide amide of bovine angiotensin II used to increase blood pressure by vasoconstriction. Angiotensinamide is indicated for the treatment of severe hypotension unresponsive to traditional pressor agents. Angiotensinamide has a strong pressure effect, due to the increased peripheral resistance of blood vessels, especially small caliber arterioles. Under the influence of angiotensinamide, the vessels of the internal organs, skin, kidneys are particularly narrowed. Blood circulation in skeletal muscles and coronary vessels does not change significantly. The drug has no direct effect on the heart and does not cause arrhythmias in therapeutic doses. Angiotensinamide is rapidly inactivated by enzymes contained in the blood, and therefore, when administered once, it has a short-term (2–3 min) pressure effect. However, the duration of the effect can be relatively easily controlled by selecting the appropriate rate of administration of the drug solution.

Droxidopa (Northera, Chelsea Therapeutics) is a synthetic catecholamino acid precursor of norepinephrine indicated for the treatment of orthostatic dizziness or lightheadedness in adult patients with symptomatic neurogenic orthostatic hypotension (NOH) caused by primary autonomic failure, dopamine beta-hydroxylase deficiency, and non-diabetic autonomic neuropathy. Droxidopa was approved as oral therapy in February 2014 under the FDA’s accelerated approval program. Droxidopa is directly metabolized to norepinephrine by dopadecarboxylase. The specific mechanism of action of the drug is not known completely, but it is supposed to exert the pharmacological effects through norepinephrine and not through the parent molecule or other metabolites. It increases blood flow to the brain by stimulating peripheral arterial and venous vasoconstriction.