Dofamine

Uses

Dofamine is recommended for the correction of haemodynamic imbalance present in-

• Acute hypotension or shock associated with myocardial infarction, endotoxic septicaemia, trauma and renal failure.
• As an adjunct after open heart surgery, where there is persistent hypotension after correction of hypovolaemia.
• In chronic cardiac decompensation as in congestive failure.

Dofamine is also used to associated treatment for these conditions: Arrhythmia, Circulatory collapse and shock, Hypotension caused by Trauma, endotoxic septicemia, Open-heart Surgery, Renal Failure, chronic cardiac decompensation, Myocardial Infarction, Urine flow decreased caused by Trauma, endotoxic septicemia, Open-heart Surgery, Renal Failure, chronic cardiac decompensation, Myocardial Infarction, Decreased cardiac output caused by Trauma, endotoxic septicemia, Open-heart Surgery, Renal Failure, chronic cardiac decompensation, Myocardial Infarction

How Dofamine works

Dofamine is a precursor to norepinephrine in noradrenergic nerves and is also a neurotransmitter in certain areas of the central nervous system. Dofamine produces positive chronotropic and inotropic effects on the myocardium, resulting in increased heart rate and cardiac contractility. This is accomplished directly by exerting an agonist action on beta-adrenoceptors and indirectly by causing release of norepinephrine from storage sites in sympathetic nerve endings. In the brain, dopamine actas as an agonist to the five dopamine receptor subtypes (D!, D2, D3, D4, D5).

Dosage

Dofamine dosage

Intravenous-Acute heart failure:

• Adult: Initially, 2-5 mcg/kg/min, increased gradually by up to 5-10 mcg/kg/min according to patient’s cardiac and urine output. Seriously ill patient: Up to 20-50 mcg/kg/min may be required.

Dilute solution (usually 1.6 mg/ml or 3.2 mg/ml) in glucose 5%, NaCl 0.9% or other suitable diluent. More dilute solution may be used where fluid expansion is not a problem.

Side Effects

Ectopic heartbeats, angina, tachycardia, palpitation, hypotension, vasoconstriction, dyspnoea, nausea, vomiting, headache, cardiac conduction abnormalities, HTN, azotemia, anxiety, widened QRS complex, bradycardia, piloerection, peripheral cyanosis.

Toxicity

LD₅₀ oral mice = 1460 mg/kg, LD₅₀ oral rats = 1780 mg/kg. Spasm or closing of eyelids, nausea, vomiting, cardiac arrhythmias, involuntary movements of the body including the face, tongue, arms, hand, head, and upper body; hypotension, haemolytic anaemia, urinary retention, duodenal ulcer, sialorrhea, ataxia, abdominal pain, dry mouth, nightmares, tachypnoea, bruxism, confusion, and insomnia.

Precaution

Patient with CV disease, cardiac arrhythmias and/or occlusive vascular disease, active myocardial ischaemia or recent MI. Correct hypovolaemia prior to treatment. Pregnancy and lactation.

Interaction

Cyclopropane and halogenated hydrocarbon anaesth may enhance the arrhythmogenic effect of dopamine. Cardiac effects are antagonised by β-adrenergic agents (e.g. propanolol, metoprolol). α-adrenergic blocking agents may antagonise the vasoconstricting effect of high dose dopamine. Prolonged and enhanced effect with MAOIs. Risk of hypotension and bradycardia with phenytoin. May potentiate diuretic effect of hydrochlorothiazide or furosemide. Enhanced vasopressor effect with TCAs and guanethidine. Risk of excessive vasoconstriction with ergot alkaloids.

Food Interaction

Dofamine Drug Interaction

Unknown: aspirin, aspirin, epinephrine, epinephrine, lorazepam, lorazepam, diltiazem, diltiazem, glucose, glucose, furosemide, furosemide, norepinephrine, norepinephrine, acetaminophen, acetaminophen, methylprednisolone, methylprednisolone, midazolam, midazolam

Dofamine Disease Interaction

Major: arrhythmias, asthmatics, dehydration, ischemic heart disease, peripheral vascular disease, pheochromocytoma

Elimination Route

Dofamine is rapidly absorbed from the small intestine.

Half Life

2 minutes

Elimination Route

It has been reported that about 80% of the drug is excreted in the urine within 24 hours, primarily as HVA and its sulfate and glucuronide conjugates and as 3,4-dihydroxyphenylacetic acid. A very small portion is excreted unchanged.

Pregnancy & Breastfeeding use

Pregnancy: It is not known whether dopamine crosses the placental barrier. The benefits of using this product should be weighed against the possible risks to the fetus.

Lactation: It is not recommended for breast-feeding mothers unless the expected benefits outweigh any potential risks.

Contraindication

Administration of dopamine is contraindicated in the following cases: Pheochromocytoma, atrial or ventricular tachyarrhythmias, ventricular fibrillation, hyperthyroidism, concurrent use with ergotamine.

Acute Overdose

Symptoms: Excessive BP elevation, vasoconstriction.

Management: Reduce dose or discontinue infusion. May also consider infusion of phentolamine mesylate.

Storage Condition

Store below 30 °C and protect from light.

Innovators Monograph

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