Enalapril: Uses And Side Effects

Enalapril is an ACEI drug, that is, it is an angiotensin converting enzyme inhibitor. It is used to treat hypertension and some types of chronic heart failure. Has it been prescribed for you or have you ever heard of it from a family member, friend or acquaintance? Don’t worry, we’ll also tell you more about it below.

The cardiovascular effects of ACEI drugs are complex and highly beneficial, both in the short and long term. Among them we can mention:

• Reduction of blood pressure.
• Decrease in cardiac hypertrophy.
• Decreased arterial remodeling.
• At the renal level, they produce an increase in renal blood flow and a moderate long-term effect on diuresis and natriuresis.

In principle, the clinical efficacy of enalapril is similar to that of the other ACE inhibitors. The differences lie in the diversity of drug potency and its various pharmacokinetic characteristics.

How does enalapril work in the body?

With the inhibition of the ACE enzyme, the main effect is the reduction of angiotensin II production. This molecule acts as a powerful peripheral vasoconstrictor and stimulates the secretion of aldosterone by the adrenal gland, increasing blood volume. Therefore, enalapril, and also the other ACE inhibitors, interfere with this process of the renin-angiotensin system.

However, the angiotensin converting enzyme also acts on other substrates, such as bradykinin, whose levels increase. In turn, bradykinin increases nitric oxide and prostaglandin levels ; hence, all of them can contribute to the final vascular effect of ACEIs.

In addition, negative feedback processes interfere, so that, in the long run, angiotensin I concentrations increase. Finally, since this could not be converted into II because the conversion enzyme is inhibited, its metabolism is diverted towards the production of angiotensin-1,7.

Pharmacokinetics: what happens to the drug in the body?

Pharmacokinetics encompasses the absorption, distribution, metabolism, and elimination processes that the drug undergoes once administered. In this sense, enclapril is administered orally and, if necessary, intravascularly. However, as the oral route is the majority, we will focus on it.

After administration, peak plasma concentrations can be observed after one hour. It has an absorption of 60% that is not affected by the presence of food in the stomach.

Once it has been absorbed, enalapril is hydrolyzed into another compound called enalaprilat , which is the true ACE inhibitor. Therefore, enalapril is a prodrug of enalaprilat, which is the molecule that will truly carry the antihypertensive action.

Enalapril excretion is primarily renal. This elimination process is, to a large extent, as an active principle, so its clearance decreases in the event that the patient suffers from kidney failure.

Adverse reactions and contraindications of enalapril

The main side effect of this drug, and in general of ACE inhibitors, is the production of a persistent dry cough, which is resistant to antitussive drugs. Enalapril stimulates the C fibers that transmit stimuli to the cough center; in addition, the accumulation of angiotensin I causes vasoconstriction that produces coughing. This adverse reaction disappears 4 days after withdrawing the treatment.

On the other hand, the following adverse effects may also appear :

• Angioedema: potentiated by kinins, forces to suspend treatment.
• Hypotension: venodilation without reflex tachycardia.
• Hyperkalemia: due to decreased release of aldosterone.
• Acute renal failure : in patients with chronic heart failure.
• Neutropenia: in patients with renal failure.

Apart from all these adverse reactions, the patient may suffer other effects not mentioned. However, all these reactions have a very low occurrence rate.

Pregnant women cannot take enalapril as it affects the fetus. Neither can patients who are allergic to any component of the formulation take it.

Interactions

Enalapril can interact with other drugs, increasing or reducing their effect or that of the concomitant medication. Its administration with NSAIDs reduces its hypotensive effect, since the latter decrease the synthesis of prostaglandins.

Another interaction that can occur is when administered with antacids, since the latter reduce the absorption of enalapril. To avoid this interaction, it is recommended to space the dose every 2 hours. Lastly, it also interacts with potassium-sparing diuretics. Their co-administration exacerbates enalapril hyperkalemia.

As we have seen, enalapril is a prescription drug indicated for the treatment of hypertension. If you are taking another medication at the time it is prescribed, you should notify your doctor in order to prevent complications. Remember, no data hurts when it comes to your health.