Pressyn AR

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

Pressyn AR may be administered subcutaneously or intramuscularly.

Ten units of Pressyn AR (0.5 mL) will usually elicit full physiologic response in adult patients; 5 units will be adequate in many cases. Pressyn AR should be given intramuscularly at 3- or 4-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 Pressyn AR 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 Pressyn AR is administered reduce such symptoms.

Abdominal Distention

In the average postoperative adult patient, give 5 units (0.25 mL) initially; increase to 10 units (0.5 mL) at subsequent injections if necessary. It is recommended that Pressyn AR be given intramuscularly and that injections be repeated at 3- or 4-hour intervals as required. Dosage to be reduced proportionately for pediatric patients.

Pressyn AR used in this manner will frequently prevent or relieve postoperative distention. These recommendations apply also to distention complicating pneumonia or other acute toxemias.

Abdominal Roentgenography

For the average case, two injections of 10 units each (0.5 mL) are suggested. These should be given two hours and one-half hour, respectively, before films are exposed. Many roentgenologists advise giving an enema prior to the first dose of Pressyn AR.

Diabetes Insipidus

Pressyn AR may be given by injection or administered intranasally on cotton pledgets, by nasal spray, or by dropper. The dose by injection is 5 to 10 units (0.25 to 0.5 mL) repeated two or three times daily as needed. When Pressyn AR is administered intranasally by spray or on pledgets, the dosage and interval between treatments must be determined for each patient.

Anaphylaxis or hypersensitivity to the drug or its components.

WARNINGS

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.

PRECAUTIONS

General

Vasopressin should be used cautiously in the presence of epilepsy, migraine, asthma, heart failure, or any state in which a rapid addition to extracellular water may produce hazard for an already overburdened system.

Chronic nephritis with nitrogen retention contraindicates the use of vasopressin until reasonable nitrogen blood levels have been attained.

Laboratory Tests

Electrocardiograms (ECG) and fluid and electrolyte status determinations are recommended at periodic intervals during therapy.

Pregnancy Category C

Animal reproduction studies have not been conducted with Pressyn AR. It is also not known whether Pressyn AR can cause fetal harm when administered to a pregnant woman or can affect reproduction capacity. Pressyn AR should be given to a pregnant woman only if clearly needed.

Labor And Delivery

Doses of vasopressin sufficient for an antidiuretic effect are not likely to produce tonic uterine contractions that could be deleterious to the fetus or threaten the continuation of the pregnancy.

Nursing Mothers

Caution should be exercised when Pressyn AR is administered to a nursing woman.

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.

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.

For medical advice about adverse reactions contact your medical professional. To report SUSPECTED ADVERSE REACTIONS, contact JHP at 1-866-923-2547 or MEDWATCH at 1-800-FDA-1088 (1- 800-332-1088) or http://www.fda.gov/medwatch/.