Negative inotropic drugs lessen the heart's workload by decreasing the rate and the strength of the heartbeat. These effects decrease the amount of blood that the heart pumps, the blood pressure in the vessels and the amount of oxygen that the heart uses. The action of these drugs also results in a decrease in the electrical activity in the heart.
The effects of these drugs make them very suitable for treating high blood pressure, angina (chest pain caused by heart disease) and heart attacks. Their effects on electrical activity make them useful for the treatment of some types of arrhythmia (irregular heart rhythm). Some of these drugs are used in the treatment of heart failure.
Although it seems contrary to what one would expect, negative inotropic drugs are sometimes used to treat heart failure, a condition in which the heart is weakened. Studies have shown that the negative inotropic drugs known as beta-blockers significantly improve heart function, symptoms, exercise performance and survival in certain types of heart failure.
Negative inotropic drugs can be divided into three classes based on how they work:
- Beta-blockers are usually used for treating high blood pressure, heart attack, chest pain, and irregular heart rhythm.
- Calcium-channel blockers are used for treating high blood pressure, chest pain, and irregular heart rhythm.
- Centrally acting sympatholytics are used for treating high blood pressure.
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