Vasopressin

INTRODUCTION

Indications

Central diabetes insipidus due to deficient antidiuretic hormone. Unlabeled Use: Management of pulseless VT/VF unresponsive to initial shocks, asystole, or pulseless electrical activity (PEA) (Advanced Cardiac Life Support guidelines). 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 Effects: ↓ urine output and ↑ urine osmolality in diabetes insipidus.

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).

PHYSICAL THERAPY IMPLICATIONS

Examination and Evaluation

• Continually monitor for signs of MI, including sudden chest pain, pain radiating into the arm or jaw, shortness of breath, dizziness, sweating, anxiety, and nausea. Seek immediate medical assistance if patient develops these signs.

• Assess heart rate, ECG, and heart sounds, especially during exercise (See Appendices G, H). Although intended to resolve severe arrhythmias, this drug can unmask or precipitate new arrhythmias (pro-arrhythmic effect). Report any rhythm disturbances or symptoms of increased arrhythmias, including palpitations, chest pain, shortness of breath, fainting, and fatigue/weakness.

• Monitor signs of excess fluid levels (water intoxication), including “pounding” headache, confusion, lethargy, irritability, decreased consciousness, and neuromuscular abnormalities (muscle weakness and cramps). Report these signs to the physician.

• Assess dizziness that might affect gait, balance, and other functional activities (See Appendix C). Report balance problems and functional limitations to the physician and nursing staff, and caution the patient and family/caregivers to guard against falls and trauma.

• Monitor signs of allergic reactions, including pulmonary symptoms (tightness in the throat and chest, wheezing, cough, dyspnea) or skin reactions (rash, pruritus, urticaria). Notify physician or nursing staff immediately if these reactions occur.

Interventions

• Because of the risk arrhythmias and MI, use extreme caution during aerobic exercise and other forms of therapeutic exercise. Assess exercise tolerance frequently (blood pressure, heart rate, fatigue levels), and terminate exercise immediately if any untoward responses occur (See Appendix L).

Patient/Client-Related Instruction

• Advise patient and family or caregivers about the signs of MI (see above under Examination and Evaluation), and to seek immediate medical assistance if these signs develop.

• Instruct patient and family/caregivers to report other troublesome side effects such as severe or prolonged fever, trembling, skin reactions (paleness, blanching around the mouth), or GI problems (nausea, vomiting, diarrhea, heartburn, belching, flatulence, abdominal cramps).

Pharmacokinetics

Absorption: IM absorption may be unpredictable.