Desmopressin

INTRODUCTION

Indications

PO, SC, IV, Intranasal: Treatment of diabetes insipidus caused by a deficiency of vasopressin. Intranasal: Controls bleeding in certain types of hemophilia and von Willebrand's disease.

Action

An analogue of naturally occurring vasopressin (antidiuretic hormone). Primary action is enhanced reabsorption of water in the kidneys. Therapeutic Effects: Prevention of nocturnal enuresis. Maintenance of appropriate body water content in diabetes insipidus. Control of bleeding in certain types of hemophilia or von Willebrand's disease.

Adverse Reactions/Side Effects

CNS: drowsiness, headache, listlessness. EENT: intranasal: nasal congestion, rhinitis. Resp: dyspnea. CV: hypertension, hypotension, tachycardia (large IV doses only). GI: mild abdominal cramps, nausea. GU: vulval pain. Derm: flushing. F and E: water intoxication/hyponatremia. Local: phlebitis at IV site.

PHYSICAL THERAPY IMPLICATIONS

Examination and Evaluation

• Be alert for an imbalance in body water and electrolytes that results in low sodium levels (hyponatremia). Signs include headache, confusion, listlessness, fatigue, irritability, muscle abnormalities (weakness, cramps, spasms), and decreased consciousness that can progress to coma and seizures. Notify physician if these signs occur.

• Assess blood pressure and compare to normal values (See Appendix F). Report changes in blood pressure, either a problematic decrease in BP (hypotension) or a sustained increase in BP (hypertension).

• Assess heart rate, ECG, and heart sounds, especially during administration of high IV doses (See Appendices G, H). Report a rapid heart rate (tachycardia) or symptoms of other such as palpitations, chest discomfort, shortness of breath, fainting, and fatigue/weakness.

• Assess any breathing problems, and report difficult or labored breathing (dyspnea).

• Assess administration site during and after IV administration, and report signs of phlebitis and venous thrombosis (local pain, swelling, inflammation).

Interventions

• Because of the risk of arrhythmias, abnormal BP responses, and pulmonary problems, use 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

• Instruct patient to report other bothersome side effects such as severe or prolonged nasal congestion (when administered intranasally), skin reactions (flushing), or GI problems (nausea, abdominal cramps).

Pharmacokinetics

Absorption: 5% absorbed following oral administration; some 10–20% absorbed from nasal mucosa.

Distribution: Distribution not fully known. Enters breast milk.

Metabolism and Excretion: Unknown.

Half-life: 75 min.