Today's drug is dobutamine.
Drug which you might familiar with its name but do you know about its indications?
INDICATIONS :
- It is a cardiac drug.
- Positive inotrope (affects the force with which the heart muscle contracts) used in cardiovascular decompensation secondary to loss of ventricular contractility as in CHF(Congestive heart failure) or after cardiac surgery.
- Positive inotrope used in CHF patients after acute myocardial infarction.
How does dobutamine work?
MECHANISMS OF ACTION :
- Dobutamine belongs to the catecholamine family and is a beta-adrenergic agonist.
- Dobutamine directly stimulate beta-1 receptors exerting a positive inotropic effect on the myocardium resulting in increased cardiac output due to improved myocardial contractility.
- Onset of Action : 1-2 mins
- Duration of Action : 5-6 mins
How is dobutamine taken?
ROUTE OF ADMINISTRATION :
- For IV(intravenous) use only.
Is there any contraindication?
CONTRAINDICATIONS :
- It is contraindicated in patients with Idiopathic Hypertophic Subaortic Stenosis (IHSS - a disease characterized by marked hypertrophy of the left ventricle, involving in particular the interventricular septum and the left ventricular outflow tract.).
Are there any possible side effects?
SIDE EFFECTS :
- Tachyarrhythmias- any disturbance of the heart rhythm in which the heart rate is abnormally increased. (atrial fibrillation patients are at increased risk), ectopy.
- Hypertension. Patients with pre-existing hypertension may show exaggerated pressor responses.
- Angina, chest discomfort, and palpitations.
- Non-cardiac related adverse effects: nausea, vomiting, paresthesias, dyspnea, headache, mild leg cramps, nervousness, and fatigue.
- Mild local pain and irritation if extravasation occurs. Infiltration can be treated with Phentolamine injection. 5 to 10 mg of phentolamine is injected subcutaneously in a pin-wheel fashion surrounding the area of infiltration. This will avoid dermal necrosis/sloughing.
- Rare hypovolemia.
What precautions are necessary?
PRECAUTIONS :
- During the administration of dobutamine, as with any adrenergic agent, ECG and blood pressure should be continuously monitored. In addition, pulmonary wedge pressure and cardiac output should be monitored whenever possible to aid in the safe and effective infusion of dobutamine.
- Hypovolemia should be corrected with suit-able volume expanders before treatment with dobutamine is instituted.
- No improvement may be observed in the presence of marked mechanical obstruction, such as severe valvular aortic stenosis.
DRUG INTERACTIONS :
- Alkaline solutions, e.g. sodium bicarbonate, inactivate dobutamine.
- Anesthetics such as halothane and cyclopropane may sensitize the heart to the effects of dobutamine resulting in ventricular arrhythmias.
- Concomitant use of dobutamine and nitroprusside results in a higher cardiac output and usually lower pulmonary capillary wedge pressure(PCWP) than with either agent alone.
- Increased vasopressor effect of dobutamine when used with bretylium, guanethidine, oxytocic drugs or TCAs (tricyclic antidepresssants).
Pregnancy and breastfeeding:
- Reproduction studies performed in rats at doses up to the normal human dose (10 mcg/kg/min for 24 h, total daily dose of 14.4 mg/kg), and in rabbits at doses up to twice the normal human dose, have revealed no evidence of harm to the fetus due to dobutamine. There are, however, no adequate and well-controlled studies in pregnant women. Because animal reproduction studies are not always predictive of human response, this drug should be used during pregnancy only if clearly needed.
- It is not known whether this drug is excreted in human milk. Because many drugs are excreted in human milk, caution should be exercised when dobutamine is administered to a nursing woman. If a mother requires dobutamine treatment, breastfeeding should be discontinued for the duration of the treatment.
References :
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