Dopexamine is used in hospitals as an inotropic agent to reduce exacerbations of heart failure and to treat heart failure following cardiac surgery. It is administered intravenuously. As of 2010 dopexamine was not often administered in cardiac care because other, more well established drugs can accomplish the same effect, other such drugs include epinephrine, dopamine, dobutamine, norepinephrine, and levosimendan. It should not be used in people taking monoamine oxidase inhibitors, nor in people who have certain adrenal cancers, low platelet counts, or people with left ventricular outlet obstruction. It also should not be used in people with severe low blood pressure or reduced systemic vascular resistance. It should be used in caution in people with ischemic heart disease especially following heart attack or a recent episode of angina due to the risk of tachycardia. It should not be used in people with reduced blood volume. Safety in pregnant women has not been established.
Adverse effects
Very common adverse effects include fast heart beats and nausea. Common adverse effects include tremor, headache, transient low blood pressure, vomiting, increased sweating, sepsis, sinus and nodal slow heart beat, cardiac arrest, myocardial infarction, cardiac enzyme changes, non-specific ECG changes, high blood pressure, hemorrhage, respiratory failure, acute respiratory distress syndrome, pulmonary edema, pulmonary hypertension, and kidney failure. Like other ß2-agonists, dopexamine lowers potassium levels and raises glucose levels, so there is a risk of exacerbating hypokalaemia or hyperglycaemia. People can develop drug tolerance to dopexamine if it is administered over a long period of time, as with other catecholamines. Dopexamine may potentiate the effects of other catecholamines like noradrenaline. Effects of depexamine may be suppressed by concomitant use with ß2-adrenergic and dopamine receptor antagonists requires caution.
Pharmacology
The half-life of IV dopexamine is 6–7 minutes in healthy adults and 11 minutes in patients with heart failure.
Mechanism of action
Dopexamine stimulates beta-2 adrenergic receptors and peripheral dopamine receptor D1 and dopamine receptor D2. It also inhibits of neuronal re-uptake of norepinephrine. These activities increase cardiac output and increase blood flow to peripheral vascular beds. It is not an α-adrenergic agonist, does not cause vasoconstriction, and is not a pressor agent. As of 2004 there was some controversy surrounding the mechanism of dopexamine. Some held that its local effects of increased tissue perfusion were due only to increased output from the heart, while others held that were direct peripheral effects.
Chemistry
Dopexamine is a synthetic analogue of dopamine, a catecholamine. Its formula may be stated 4--hexyl]amino]ethyl]-1,2-benzenediol or 4--amino]ethyl]pyrocatechol. Chinese manufacturers dominated the market for the active pharmaceutical ingredient as of 2015.
History
Dopexamine was discovered by scientists at Fisons and Fisons received the USAN name dopexamine in 1985 for its compound, then called FPL 60278. The drug was marketed by 1992 and by 1996 had been approved in several countries. Fisons licensed the rights to Ipsen in 1993, and Ipsen in turn licensed the rights to Elan in 1999. The patent on dopexamine was controlled by Elan when it expired in 2003. Dopexamine was approved for use in the European Union for treatment of symptoms related to heart failure in 2010. In 2008 the UK company Circassia acquired the US, Canadian, and Japanese marketing rights to dopexamine from Ipsen; at the time, the company said it was planning to develop a new formulation of dopexamine in combination with fluids delivered via IV fluids, looking to improve outcomes following surgery. As of 2008 dopexamine had not been approved for any use in the US, Canada, or Japan. A Teva recalled batches of dopexamine in the UK in 2014 due to quality control issues by the manufacturer, Cephalon.
Research
Use in sepsis has been explored in clinical trials, but use of an inotropic agent like dobutamine or dopexamine did not reduce mortality compared with norepinephrine or epinephrine. Use of dopexamine may be harmful in sepsis
