The main advantage of milrinone over amrinone for long-term use is the lack of which adverse effect?

The main advantage of milrinone over amrinone for long-term use is the lack of which adverse effect?

• A. Tachycardia
• B. Hypothyroidism
• C. Thrombocytopenia
• D. Hyperglycemia

Answer: (C)

Milrinone and amrinone both increase cardiac contractility and cause vasodilation by inhibiting phosphodiesterase type 3, raising cAMP in heart muscle and vessels. The important difference for long-term use is hematologic toxicity: amrinone is more likely to cause thrombocytopenia, which can limit continued therapy and raise bleeding risk. Milrinone, by contrast, has a much lower incidence of thrombocytopenia, making it preferable for prolonged treatment. Other adverse effects, like tachycardia, can occur with both drugs and aren’t unique advantages of milrinone, and hypothyroidism or hyperglycemia are not typical concerns with these agents.

Milrinone and amrinone both increase cardiac contractility and cause vasodilation by inhibiting phosphodiesterase type 3, raising cAMP in heart muscle and vessels. The important difference for long-term use is hematologic toxicity: amrinone is more likely to cause thrombocytopenia, which can limit continued therapy and raise bleeding risk. Milrinone, by contrast, has a much lower incidence of thrombocytopenia, making it preferable for prolonged treatment. Other adverse effects, like tachycardia, can occur with both drugs and aren’t unique advantages of milrinone, and hypothyroidism or hyperglycemia are not typical concerns with these agents.