VASOPRESSIN INJECTION, USP (SYNTHETIC)

Vasopressin Injection, USP is a sterile solution of synthetic vasopressin of the posterior pituitary gland for intramuscular (IM) or subcutaneous use. It is substantially free from the oxytocic principle and is standardized to contain 20 pressor units/mL. The chemical name is Vasopressin, 8-L-arginine and has the following structural formula:

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Each mL contains:  20 USP Vasopressin Units, chlorobutanol (anhydrous) 5 mg as preservative; Water for Injection q.s. Glacial acetic acid and/or sodium hydroxide may have been added for pH adjustment (2.4-4.5).

The antidiuretic action of vasopressin is ascribed to increasing reabsorption of water by the renal tubules.

Vasopressin can cause contraction of smooth muscle of the gastrointestinal tract and of all parts of the vascular bed, especially the capillaries, small arterioles and venules with less effect on the smooth musculature of the large veins. The direct effect on the contractile elements is neither antagonized by adrenergic blocking agents nor prevented by vascular denervation. 

Following subcutaneous or intramuscular administration of vasopressin injection, the duration of antidiuretic activity is variable but effects are usually maintained for 2 to 8 hours. 

The majority of a dose of vasopressin is metabolized and rapidly destroyed in the liver and kidneys. Vasopressin has a plasma half-life of about 10 to 20 minutes. Approximately 5% of a subcutaneous dose of vasopressin is excreted in urine unchanged after 4 hours.

Vasopressin Injection, USP is indicated for prevention and treatment of postoperative abdominal distention, in abdominal roentgenography to dispel interfering gas shadows and in diabetes insipidus.

Anaphylaxis or hypersensitivity to the drug or its components.

This drug should not be used in patients with vascular disease, especially disease of the coronary arteries, except with extreme caution. In such patients, even small doses may precipitate anginal pain, and with larger doses, the possibility of myocardial infarction should be considered. 

Vasopressin may produce water intoxication. The early signs of drowsiness, listlessness and headaches should be recognized to prevent terminal coma and convulsions.

Local or systemic allergic reactions may occur in hypersensitive individuals. The following side effects have been reported following the administration of vasopressin:

Body as a Whole

Anaphylaxis (cardiac arrest and/or shock) has been observed shortly after injection of vasopressin.

Cardiovascular

Cardiac arrest, circumoral pallor, arrhythmias, decreased cardiac output, angina, myocardial ischemia, peripheral vasoconstriction, and gangrene.

Gastrointestinal

Abdominal cramps, nausea, vomiting, passage of gas.

Nervous System

Tremor, vertigo, "pounding" in head.

Respiratory

Bronchial constriction.

Skin and Appendages

Sweating, urticaria, cutaneous gangrene.

Overdosage

Water intoxication may be treated with water restriction and temporary withdrawal of vasopressin until polyuria occurs. Severe water intoxication may require osmotic diuresis with mannitol, hypertonic dextrose, or urea alone or with furosemide.

Vasopressin Injection may be administered IM or subcutaneously.

Ten units (0.5 mL) of Vasopressin Injection will usually elicit full physiologic response in adult patients; 5 units (0.25 mL) will be adequate in many cases. Vasopressin Injection should be given IM at three or four hour intervals as needed. The dosage should be proportionately reduced for pediatric patients. (For an additional discussion of dosage, consult the sections below.)

When determining the dose of Vasopressin Injection for a given case, the following should be kept in mind:

It is particularly desirable to give a dose not much larger than is just sufficient to elicit the desired physiologic response. Excessive doses may cause undesirable side effects-blanching of the skin, abdominal cramps, nausea-which, though not serious, may be alarming to the patient. Spontaneous recovery from such side effects occurs in a few minutes. It has been found that one or two glasses of water given at the time Vasopressin Injection is administered reduces such symptoms.

Store at 20° to 25°C (68° to 77°F) [see USP Controlled Room Temperature].

Do not freeze.

Vial stoppers do not contain natural rubber latex.

APP

APP PHARMACEUTICALS, LLC

Schaumburg, IL 60173

45875E

Revised:  March 2010

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