الدوبامين والدبيوتامين..الفرق والاستخدام

Dopamine Hydrochloride

&
Dobutamine Hydrochloride










Dopamine Hydrochloride


Drug Classes:

· Sympathomimetic

· Alpha –Adrenergic agonist

· Beta1-selective adrenergic agonist

· Dopaminergic drug



Therapeutic actions


* Dopamine, the most widely used inotropic drug

* It’s administered to patients with conditions that cause hypotension, decreased cardiac output, and oliguria.


* Dopamine directly stimulates dopaminergic, beta-adrenergic, and alpha-adrenergic receptors and promotes release of norepinephrine from sympathetic nerve terminals.

* Dopamine is given by continuous IV infusion and its dose is titrated to achieve the desired effect.

* Doses of 3 μg/kg/minute or less stimulate vasodilatation of the renal arterioles and may improve renal function.


* Increased myocardial contractility results from dosages of 3 to 10 μg/kg/minute.

* Higher dosages predominantly cause vasoconstriction and increased blood pressure.

* Dopamine is usually given through a central line to enhance its distribution and to avoid extravasation, which may cause local vasoconstriction and tissue necrosis.






Indications


· Correction of hemodynamic imbalances present in the shock syndrome due to MI, trauma, endotoxic septicemia, open heart surgery, renal failure, and chronic cardiac decopansation in CHF




Contraindications & Cautions


· Contraindicated with pheochromocytoma, tachyarrhythmia ventricular fibrillation, hypovolemia

· Use cautiously with atherosclerosis. Arterial embolism, cold injury, pregnancy, lactation






Adverse effects


· CV: Ectopic beats, tachycardia, anginal pain, palpitation, hypotension, vasoconstriction, dyspnia, bradycardia, hypertension, widened QRS

· GI: Nausea, vomiting

· Other: Headache, gangrene with prolong use



Interaction

Drug-drug





· Increased risk of hypertension with Furazolidone, methyldopa



· Seizures, hypotension, bradycardia when infused with phenytoin


· Decreased cardiostimulating effects with guanethidine





Dobutamine Hydrochloride



Drug classes:


· Sympathomimietic

· Beta1-selective adrenergic agonist


Therapeutic actions


* Dobutamine acts on beta1 receptors and increases myocardial contractility.

* Dobutamine is used after cardiac surgery, during some cardiac diagnostic stress procedures, and for patients with heart failure, shock, or other conditions that cause poor cardiac contractility or a low cardiac output.

* The dosage for dobutamine is 2 to 20 μg/kg/minute by continuous IV infusion


Indications


· For inotropic support in the short term treatmnt of adults with cardiac decompansation due to depressed contractility, resulting frrom either organic heart disease or from cardiac surgical procedures




Contraindications & Cautions




· Contraindicated with IHSS; hypovolemia, acute MI, pregnancy

· Use cautiously with D.M, lactation, allergy to sulphate, more common in asthmatic patients







Adverse effects

· CNS: Headache

· CV: Increase heart rate, increase in systolic blood pressure, PVCs, anginal pain, palpitaion, shortness of braeth

· GI: Nausea


Interaction

Drug-drug




· Decreased effects of guanethidine with dobutamine

· Increased risk of arrhythmias with bretylium





Calculations:

Dose (Micro) x Wt x volume x 60


Concentration x 1000

Example
Start 5 Mic dopamine for pt consider Wt 60 kg,
Volume: كمية المحلول المراد وضع الدوبامين فيها
Consider 500 cc-ml
Concentration of dopamine consider 200mg
1000: ثابت
60 = 1 hour
الحل:
(5 Mic *60 kg*500 ml *60 ) / (200 mg*1000)

= 9000000 / 200000
= 45 ml / hour
اذا 45 مل لكل ساعة

مع ملاحظة ان اعطاء الدوبامين عن طريق
Infusion === Dropper Machine
وكذلك ينطبق على الدوبيوتامين


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