General

Pronunciation
vay-soe-PRESS-in

Trade Name(s)

• Pitressin

• Pressyn [Canada]

Pregnancy Category
Category C

Ther. class.
hormones

Pharm. class.
antidiuretic hormones

Indications

Central diabetes insipidus due to deficient antidiuretic hormone

Unlabelled Use(s):

• Management of pulseless VT/VF unresponsive to initial shocks, asystole, or pulseless electrical activity (PEA) (ACLS guidlines)

• Septic shock

Action

• Alters the permeability of the renal collecting ducts, allowing reabsorption of water

• Directly stimulates musculature of GI tract

• In high doses acts as a nonadrenergic peripheral vasoconstrictor

Therapeutic Effect(s):
Decreased urine output and increased urine osmolality in diabetes insipidus

Pharmacokinetics

Absorption: IM absorption may be unpredictable

Distribution: Widely distributed throughout extracellular fluid

Metabolism and Excretion: Rapidly degraded by the liver and kidneys; <5% excreted unchanged by the kidneys

Half-life: 10–20 min

TIME/ACTION PROFILE (antidiuretic effect)

ROUTE	ONSET	PEAK	DURATION
IM, subcut	unknown	unknown	2–8 hr
IV	unknown	unknown	30–60 min

Contraindication/Precautions

Contraindicated in:

• Chronic renal failure with increased BUN

• Hypersensitivity to beef or pork proteins

Use Cautiously in:

• Perioperative polyuria (increased sensitivity to vasopressin)

• Comatose patients

• Seizures

• Migraine headaches

• Asthma

• Heart failure

• Cardiovascular disease

• Geri: Pedi: Geriatric patients and children ( sensitivity to vasopressin)

• Renal impairment

Adverse Reactions/Side Effects

CNS: dizziness, "pounding" sensation in head.

CV: MI, angina, chest pain.

GI: abdominal cramps, belching, diarrhea, flatulence, heartburn, nausea, vomiting.

Derm: paleness, perioral blanching, sweating.

Neuro: trembling.

Misc: allergic reactions, fever, water intoxication (higher doses).

*CAPITALS indicates life-threatening.
*italic indicates most frequent.

Interactions

Drug-Drug

• Antidiuretic effect may be by concurrent administration of alcohol, lithium, demeclocycline, heparin, or norepinephrine

• Antidiuretic effect may be by concurrent administration of carbamazepine, chlorpropamide, clofibrate, tricyclic antidepressants, or fludrocortisone

• Vasopressor effect may be by concurrent administration of ganglionic blocking agents

Route/Dosage

• IM, SC (Adults): 5–10 units 2–4 times daily.

• IM, SC (Children): 2.5–10 units 2–4 times daily.

• IV (Adults):
Pulseless VT/VF, asystole, or PEA (ACLS guidelines)—40 units as a single dose (unlabeled).
Septic shock-0.04 units/min infusion.

Availability

• Injection: 20 units/ml in 0.5- and 1-ml ampules and vials

Assessment

• Monitor BP, HR, and ECG periodically throughout therapy and continuously throughout cardiopulmonary resuscitation

Diabetes Insipidus

• Monitor urine osmolality and urine volume frequently to determine effects of medication. Assess patient for symptoms of dehydration (excessive thirst, dry skin and mucous membranes, tachycardia, poor skin turgor). Weigh patient daily, monitor intake and output, and assess for edema

Lab Test Considerations

• Monitor urine specific gravity throughout therapy

» Monitor serum electrolyte concentrations periodically during therapy

Toxicity and Overdose

• Signs and symptoms of water intoxication include confusion, drowsiness, headache, weight gain, difficulty urinating, seizures, and coma

» Treatment of overdose includes water restriction and temporary discontinuation of vasopressin until polyuria occurs. If symptoms are severe, administration of mannitol, hypertonic dextrose, urea, and/or furosemide may be used

Potential Nursing Diagnoses

• Deficient fluid volume (Indications)

• Excess fluid volume (Adverse Reaction)

Implementation

Do not confuse Pitressin (vasopressin) with Pitocin (oxytocin)

» Aqueous vasopressin injection may be administered subcut or IM for diabetes insipidus

» Administer 1–2 glasses of water at the time of administration to minimize side effects (blanching of skin, abdominal cramps, nausea)

IV Adminstration:

• Direct IV:
Diluent: Administer undiluted.
Concentration: 20 units/ml

• Rate:
Administer over 1–2 sec during pulseless VT/VF, asystole, or PEA

• Continuous Infusion:
Diluent: Dilute 100 units of vasopressin in 250 ml of 0.9% NaCl or D5W.
Concentration: 0.4 units/ml

• Rate:
See Route/Dosage section

• Y-Site Compatibility:

» amiodarone

» argatroban

» ciprofloxacin

» diltiazem

» dobutamine

» dopamine

» drotrecogin

» epinephrine

» fluconazole

» gentamicin

» heparin

» imipenem/cilastatin

» insulin

» lidocaine

» linezolid

» meropenem

» metronidazole

» milrinone

» nitroglycerin

» norepinephrine

» pantoprazole

» phenylephrine

» procainamide

» sodium bicarbonate

• Y-Site Incompatibility:

» diazepam

» phenytoin

» trimethoprim/sulfamethoxazole

Patient/Family Teaching

• Instruct patient to take medication as directed. Caution patient not to use more than prescribed amount. Take missed doses as soon as remembered, unless almost time for next dose

• Advise patient to drink 1–2 glasses of water at time of administration to minimize side effects (blanching of skin, abdominal cramps, nausea). Inform patient that these side effects are not serious and usually disappear in a few minutes

• Caution patient to avoid concurrent use of alcohol while taking vasopressin

• Patients with diabetes insipidus should carry identification at all times describing disease process and medication regimen

Evaluation/Desired Outcomes

• Decrease in urine volume

» Relief of polydipsia

» Increased urine osmolality in patients with central diabetes insipidus

• Resolution of VT/VF

• Improvement in signs of septic shock

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