Quiz 36: Pharmacotherapy of Heart Failure
Digoxin is the drug used to increase the contractility of the heart. The furosemide is the diuretic drug which lowers the blood volume and hence blood pressure. The furosemide leads to the low concentration of potassium in the blood due to which the potassium supplementation is eesential. The combination of these drugs provides the effective way of dealing with heart failure. The potassium supplementation is necessary along with this medication to deal with hypokalemia (low potassium ions in the blood) due to furosemide.
Propanolol is a negative ionotropic agent and it should be used with care in the patients with heart failure and asthma. This is because the negative ionotropic agents decrease the contractility (contraction force) of the heart which may worsen the heart failure condition. The negative ionotropic agents also have a side effect on the bronchioles causing their constriction. This constriction creates difficulty to the asthmatic patient. Thus, these agents should be used with care in heart failure patients and asthmatic patients.
The strong force of contraction of the heart is important to deal with heart failure. The cAMP (cyclic adenosine monophosphate) is important for the contraction which further activates protein kinase A (PKA). The PKA ultimately acts to increase the force of contraction of the heart. Phosphodiesterase is the enzyme which breakdowns the cAMP and thus, PKA gets reduced and is notable to increase the force of contraction in the heart. The milrinone is the drug which is phosphodiesterase 3 inhibitor. It acts by blocking the action of phosphodiesterase enzyme. Hence, the concentration of the cAMP and PKA will be sufficient to increase the force of contraction in the heart. In this way, the milrinone helps or acts in heart failure.