Brand Name
Pitressin, Pressyn (CAN)
Class and Category
Chemical class: Polypeptide hormone
Therapeutic class: Antidiuretic
Pregnancy category: C
To prevent or control symptoms of central diabetes
insipidus caused by insufficient ADH
I.M. OR SUBCUTANEOUS INJECTION
Adults. 5 to 10 units b.i.d. or t.i.d., as needed.
Children. 2.5 to 10 units t.i.d. or q.i.d., as needed.
To prevent or treat abdominal distention
I.M. INJECTION
Adults. 5 units, increased to 10 units every 3 to 4 hr, as needed.
Mechanism
of Action
Vasopressin,
a synthetic form of antidiuretic hormone, treats diabetes insipidus by
decreasing urine output and raising urine osmolality. When vasopressin attaches
to vasopressin2 (V2) receptors on cell membranes in the nephron’s collecting
duct, it activates the enzyme adenyl cyclase to convert adenosine triphosphate
(ATP) to cyclic adenosine monophosphate (cAMP). This action increases the
collecting duct’s permeability and enhances water reabsorption into the blood.
Route Onset Peak
Duration
I.M., SubQ Unknown
Unknown 2–8 hr
Contraindications
Chronic nephritis with nitrogen retention, hypersensitivity to
vasopressin or its components
Interactions
DRUGS
carbamazepine, chlorpropamide, clofibrate, fludrocortisone,
tricyclic antidepressants: Increased antidiuretic effect
demeclocycline, lithium, norepinephrine: Decreased
antidiuretic effect
Adverse Reactions
CNS: Dizziness, headache, light-headedness, tremor
CV: Angina, MI
EENT: Circumoral pallor
ENDO:Water intoxication
GI: Abdominal cramps, diarrhea, eructation, flatulence, intestinal
hypermotility, nausea, vomiting
SKIN: Diaphoresis, pallor
Other: Allergic
reaction
Nursing
Considerations
•
Use vasopressin with extreme caution in patients with coronary artery disease because
it may cause angina or MI; in those with hypertension because it may increase
blood pressure; and in those with asthma, epilepsy, heart failure, or migraine headache
because extracellular fluid may increase rapidly.
•Monitor
fluid and electrolyte balance during therapy. Check intake and output at least
every 8 hours, and watch for evidence of water intoxication and hyponatremia, including
anuria, confusion, drowsiness, headache, listlessness, and weight gain.
PATIENT
TEACHING
•
Teach patient how to administer vasopressin; stress the need to rotate
injection sites.
•
Urge patient to notify prescriber immediately if he has evidence of possible
water intoxication, including anuria, confusion, drowsiness, headache,
listlessness, and unexplained weight gain.
•
Inform patient that abdominal cramps, nausea, and skin blanching will subside after
a few minutes and can be minimized by drinking one or two glasses of water.
