antihypertensive effects of guanethidine may be partially or totally
reversed by the mixed-acting sympathomimetics
use metaraminol with caution in digitalised patients, because
the combination of digitalis and sympathomimetics amines may
cause etopic arrhythmias
Halogenated hydrocarbon anesthetics
halogenated hydrocarbon anesthetics may sensitise the effects of
catecholamines. Use of vasopressors may lead to serious
arrthythmias, use with extreme caution
Monoamine oxidase inhibitors
MAOIs increase the pressor response to mixed-acting vasopresors. Possible hypertensive crisis and intracranial hemorrhage may occur. This interaction may also occur with
furazolidone, an antimicrobial with MAOI activity. Avoid this combination
if vasopressor drugs are used in obstertics to correct hyoptension
or added to local anesthetic solution, some oxytocic drugs may
cause severe persistent hypertension
the vasopressor response of the mixed-acting vasopressors may
be decreased by tricyclic antidepressants, a higher dose of the
sympathomimetic may be necessary
Cardiovascular- Sympathomimetics amines may cause sinus or ventricular tachycardia or arrhythmias, especially in patients with MI. Hypertension, hypotension following cessation of the drug cardiac arrhythmias, cardiac arrest and palpitations have occured.
Cirrhosis- treat patients cautiousl and with adequate restoration of electrolyes if diuresis ensures.
Cumulative effects- because of its prolonged action, a cummulative effect is possible. It is important to make frequent assesesment of the blood pressure, particularly when administering IV.
Extravasation- excercise care when selecting the site of administration of this drud, particularly when giving by the IV route.
Malaria- sympathomimetic amines may provoke a relapse in patients with a history of malaria.
Cardiac effects- metaraminol may cause cardiac arrhythmias. This may be particularly dangerous in patients with myocardial infarction or in patients who have received anesthetics which sensitize the heart to catecholamines ie cyclopropane,halothane
Pregnancy- give metaraminol to a pregnant woman only if clearly needed.
Lactation- excercisecaution when giving metaraminol to a nursing woman.
Children- safety and effectiveness in children have not been established.
Dosages/ Overdosage Etc:
Acute hypotensive states
May be given IM,Sc or IV- recommended dose is 2 to 10mg.
Overdosage with metaraminol may cause convulsions, severe hypertension, headache, constricting sensation in the chest, nausea, vomiting, euphoria, disphoresis, pulmonary edema, tachycardia, bradycardia, sinus arrhythmia artial or ventricular arrhythmias, myocardial infarction, cardiac arrest, cerebral hemorrhage or cardiac arrhythmias
Patients with hyperthyroidism or hypertension are particularly sensitive to these effects.
1. An appropiate antiarrhythmic agent may be required.
1. If you are using this medicine regularly and you miss a dose, use it as soonas possible.
2. Then use the remaining dose fotbthat day at regularly spaced intervals.
3. Do not double doses.
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