Pitressin (vasopressin, antidiuretic hormone, ADH)

Introduction

Tradename: Pitressin.

Indications

• used to control polyuria, polydipsia & dehydration in patients with diabetes insipidus
• used to control massive hemorrhage
• adjunct in treatment of GI hemorrhage & bleeding esophageal varices
• prevention & treatment of post-operative abdominal distension

Contraindications

Caution:

• seizure disorder
• migraine
• asthma
• vascular disease
• renal disease
• cardiac disease

Pregnancy category: C

Safety in lactation ?

Dosage

• diabetes insipidus:
  • adults: 5-10 units IM/SC BID-QID PRN (5-60 units/day)
  • children: 2.5-5 units IM/SC BID-QID PRN
  • intranasal spray
• variceal bleeding: 100 units in 250 mL D5W (0.4 I/mL) IV at 6-24 U/hour (15-60 mL/hour)
• abdominal distension
  • 5 units IM stat
  • 10 units every 3-4 hours

Injection: 20 units/mL (1 mL)

Pharmacokinetics

• elimination: liver, kidney

Adverse effects

• not common (1-10%)
  • sweating, pounding in the head, hypertension, bradycardia, arrhythmias, venous thrombosis, vasoconstriction with higher doses, angina, tremor, vertigo, fever, urticaria, abdominal cramps, nausea/ vomiting, circumoral pallor, flatus
• uncommon (< 1%)
  • allergic reaction, myocardial infarction, water intoxication

Mechanism of action

• maintains serum osmolality by increasing passive resorption of water by the distal renal tubules
  • enables urine osmolality to reach 800-1200 mosm/kg
  • without ADH, urine osmolality reaches only 60-60 mosm/kg
• causes vasoconstriction of the capillaries & small arterioles
• release of ADH from the hypothalamus is stimulated by:
  • plasma osmolality > 280 mosm/kg
    • plasma ADH levels zero for osmolality < 280 mosm/kg
    • plasma ADH levels linearly related to osmolality for values > 280 mosm/kg
    • the organum vasculosum lamina terminalis is a chemoreceptor trigger zone in brain that senses osmolality
  • hypotension
  • decrease in plasma volume (7-10%)
  • decrease in effective plasma volume
    • cirrhosis
    • congestive heart failure
• Pitressin elicits all of the pharmacologic responses of endogenous vasopressin

More general terms

• vasopressin (antidiuretic hormone, ADH)
• endocrine agent
• gastrointestinal agent

Additional terms

• arginine vasopressin (Argipressin, AVP)
• desmopressin (deamino-arginine vasopressin, dDAVP, dDVP, Noctiva, Stimate, Minirin)
• organum vasculosum lamina terminalis (OVLT)
• osmolality (Osm)
• prepro-vasopressin; vasopressin-neurophysin 2 copeptin (AVP)
• vasopressin receptor antagonist (vaptan)
• vasopressin receptor or antidiuretic hormone [ADH] receptor