Milrinone

INTRODUCTION

Indications

Short-term treatment of CHF unresponsive to conventional therapy with digoxin, diuretics, and vasodilators.

Action

Increases myocardial contractility. Decreases preload and afterload by a direct dilating effect on vascular smooth muscle. Therapeutic Effects: Increased cardiac output (inotropic effect).

Adverse Reactions/Side Effects

CNS: headache, tremor. CV: VENTRICULAR ARRHYTHMIAS, angina pectoris, hypotension, supraventricular arrhythmias. CV: skin rash. GI: liver function abnormalities. F and E: hypokalemia. Hemat: thrombocytopenia.

PHYSICAL THERAPY IMPLICATIONS

Examination and Evaluation

• Assess heart rate, ECG, and heart sounds, especially during exercise (See Appendices G, H). Report any rhythm disturbances or symptoms of increased arrhythmias, including palpitations, chest discomfort, shortness of breath, fainting, and fatigue/weakness.

• Assess signs and symptoms of CHF (dyspnea, rales/crackles, peripheral edema, jugular venous distention, exercise intolerance) to help document whether drug therapy is effective in reducing these symptoms.

• Assess blood pressure periodically and compare to normal values (See Appendix F). Report low blood pressure (hypotension), especially if patient experiences dizziness, fatigue, or other symptoms.

• Report any muscle weakness, aches, or cramps that might indicate low potassium levels (hypokalemia).

• Monitor and report signs of thrombocytopenia (bruising, nose bleeds, bleeding gums).

Interventions

• Design and implement aerobic exercise and endurance training programs to improve myocardial pumping ability and reduce symptoms of CHF.

• Use caution during aerobic exercise and endurance conditioning because of an increased risk of cardiac arrhythmias. Terminate exercise if patient exhibits untoward symptoms (chest pain, shortness of breath, etc.), or displays other criteria for exercise termination (See Appendix L).

Patient/Client-Related Instruction

• Remind patients to take medication as directed to control CHF even if they are asymptomatic.

• Instruct patients to weigh themselves every day, and call their physician if they gain 3 lb or more in 1 day or more than 5 lb in 1 week. Sudden weight gain may indicate fluid buildup due to worsening heart failure.

• Counsel patients about additional interventions to help control cardiac dysfunction, including regular exercise, weight loss, sodium restriction, stress reduction, moderation of alcohol consumption, and smoking cessation.

• Instruct patient to report signs of liver dysfunction, including yellow skin or eyes, abdominal pain, severe nausea and vomiting, fever, sore throat, malaise, weakness, and facial edema.

• Instruct patient or family/caregivers to report other troublesome side effects such as severe or prolonged headache, tremor, or skin rash.

Pharmacokinetics

Absorption: IV administration results in complete bioavailability.

Distribution: Unknown.

Metabolism and Excretion: 80–90% excreted unchanged by the kidneys.

Half-life: 2.3 hr (increased in renal impairment).