Dopexamine

Dopexamine - is the synthetic analogue of dopamine. It has potent B2 activity with one-third the potency of dopamine on dopamine 1 receptor. There is no a activity. Dopexamine increases HR and CO, causes peripheral vasodilatation, renal and splanchnic blood flow and ↓PCWP. Current interest in dopexamine is centred on its dopaminergic and anti-inflammatory activity. The anti-inflammatory activity and improved splanchnic blood flow may be due to dopexamine’s B2 rather than DA 1 effect.The usual dose for its anti-inflammatory activity and to improve renal, mesenteric, splanchnic and hepatic blood flow is between 0.25 and 0.5 μg/kg/min. In comparison with other inotropes, dopexamine causes less increase in myocardial oxygen consumption.

Uses:
To improve renal, mesenteric, splanchnic and hepatic blood flow Short-term treatment of acute heart failure

Contraindications:
Concurrent MAOI administration
Left ventricular outlet obstruction (HOCM, aortic stenosis)
Phaeochromocytoma

Administration:
Correction of hypovolaemia before starting dopexamine
• Dose: start at 0.25 μg/kg/min, increasing up to 6 μg/kg/min Titrate according to patient’s response: HR, rhythm, BP, urine output
and, whenever possible, cardiac output 50 mg made up to 50 ml glucose 5% or sodium chloride 0.9% (1000 μg/ml)

Dosage chart (ml/h)

Weight (kg)	Dose (ug/kg/min)
	0.25	0.5	1	2	3
50	0.8	1.5	3.0	6.0	9.0
60	0.9	1.8	3.6	7.2	10.8
70	1.1	2.1	4.2	8.4	12.6
80	1.2	2.4	4.8	9.6	14.4
90	1.4	2.7	5.4	10.8	16.2
100	1.5	3.0	6.0	12.0	18.0
110	1.7	3.3	6.6	13.2	19.8
120	1.8	3.6	7.2	14.4	21.6

How not to use dopexamine
Do not connect to CVP lumen used for monitoring pressure (surge of drug during flushing of line)
Incompatible with alkaline solutions, e.g. sodium bicarbonate, frusemide, phenytoin and enoximone

Adverse effects
Dose-related increases in HR
Hypotension
Angina
Hypokalaemia
Hyperglycaemia

Cautions
Thrombocytopenia (a further decrease may occur)
IHD (especially following acute MI)