Interacting drugs- summary

Dopamine + 

Guanethidine-                                                                                                                    antihypertensive effects of guanethidine may be partially or totally reversed by mixed-acting sympathomimetics 

Phenytoin-                                                                                                                     concomittant infusion of dopamine has been reported to lead to seizures, severe hypotension and bradycardia. If necessary discontinue phenytoin and provide supportive treatment 

Tricyclic antidepressants-                                                                                                    pressor response of the mixed-acting vasopressors may be decreased by these agents; a higher dose of these sympathomimtic may be necessary

Myocardial syndrome,trauma,endotoxic septicaemia,open heart surgery,renal failure. 

VASSOPRESSORS USED IN SHOCK- includes-

Inotropic effects - Isoproternol, Dobutamine, Dopamine, Ephinephrine, Mixed effects- Norephinephrine, Ephedrine, Mephentermine Pressors effects- Metaraminol Methoxamine Phenylephrine 

Most frequent- Ectopic beats, nausea, vomiting, tachycardia, angina pain, palpitation, dyspnea, headache, hypotension,vasoconstriction. Infrequent - berrant conduction, bradycardia, piloerection widened QRS complex, azotemia, elevated pressure.

Gangrene has occurred when high doses were administered for prolonged periods and in patients with occlusive vascular disease receiving low doses of dopamine

Pheochromocytoma, uncorrected tachyarrhythmias or ventricular fibrillation

Special precautions:

Hypovolemia- Prior to treatment with dopamine correct hypovalemia with either whole blood as indicated.

Monitoring- close monitoring of urine flow, cardiac output, pulmonary wedge pressure and blood pressure during infusion is necessary.

Decreased pulse pressure- if a dispropionate rise in the diastolic pressure ) a marked decrease in pulse pressure) is observed in patients receiving dopamine, decrease infusion rate and observe patient carefully for further evidence of predominance vasoconstriction , unless such an effect is desired.

Occulsive vascular disease- Closely monitor patients with a history of occular vascular disease (eg arteriosclerosis, arterial embolism ), Reynauds disease, cold injury, frostbite, diabetic endarteritis and Buergers disease) or for any changes in color or temperature of the skin of the extremities. This condition may be reversed by either decreasing the rate of infusion or discontinuing the drug.

Extravasation- Infuse into large vein to prevent extravastion.Monitor the infusion site closely for free flow. Closely monitor urine flow,cardiac output and blood pressure during infusion.

Discontinuation- when discontinuting the infusion, gradualy decrase the dose of dopamine since sudden cessation, may resulting marked hypotension.

Sulfite sensitivity- some of these products contain sulfites that may cause allergic type reactions including anaphylactic symptoms and life threatening or less severe asthmatic episodes in certain susceptible individuals.

Warnings-

Polyuria- doses < 3mcg/kg/min have been shown to improve kidney function

Pregnancy- the drug may be used in pregnant women when the expected benefits outweigh the potential risk to the fetus.

Lactation- excercise caution when administering to a nursing woman.

Children-safety and efficacy for use in children have not been established.

Date of Approval       2002

Indications:

Myocardial syndrome,trauma,endotoxic septicaemia,open heart surgery,renal failure.

Dosage:

A potent drug.Dilute before use. Administer at rates greater than 50mcg/kg/min Suggested - Begin at 2 to 5mcg/kg/min,increase gradually. at 5 to 10mcg/kg/min increments upto 20 to 50mcg/kg/min as needed.

Overdosage-

Symptoms- Accidental overdosage is manifested by excessive blood pressure elevation

Treatment

1. Reduce rate of administration or temporarily discontinue until patients condition is stabilized.

2. Since duration of action is quite short no additional remedial measures are usually necessary.

3. If these measures fail to stabilize the patients condition consider using the short acting alpha-adrenergic blocking agent, phentolamine

Missed dose-

1. If you miss a dose of this medicine, take it as soon as possible.

2. However, if it is almost time for next dose, skip the missed dose and go back to your regular dosing schedule.

. Do not double doses.

Drugs causing adverse reactions- ( 388 )

1. Centrally acting hypertensive (Reserpine, Methyldopa, Dopamine)

2. Propranalol

3. Corticosteroids

4. MAOI

5. Tricyclic antidepressants

1. This is a potent drug. Dilute before use

2. After dilution, administer IV . A metering dose is essential for controlling the rate of flow

3. Protect from loght. Do not use if the solution is discolored

4. Store at room temperature 15 to 30C.

VASSOPRESSORS USED IN SHOCK- includes

Inotropic effects - Isoproternol, Dobutamine, Dopamine, Ephinephrine, Mixed effects- Norephinephrine, Ephedrine, Mephentermine Pressors effects- Metaraminol Methoxamine Phenylephrine 

Pharmacology:

Dopamine is an endogenous catecholamine and a precursor of norepinephrine. It acts directly and indirectly (releases norepinephrine stores) on alpha and beta1 receptors and has dopaminergic effects. Dopamine causes less increase inmyocardial oxygen consumption than isoproterenol and is usually not associated with tachyarrhythmia.

Pharmacokinetics:

Dopamine has an onset of action within 5 minutes, a plasma half-life of about 2 minutes and a duration of action of less than 10 minutes. The drug is widely distributed in the body but does not cross the blood-brain barrier.

Pregnancy:

The drug may be used in pregnant women when the expected benefits outweigh the potential risk to the fetus

Lactation:

Excercise caution when administering to a nursing woman. Children- Safety and efficacy for use in children have not been established.