Enalapril

Enalapril is a drug from the group of so-called angiotensin-conversion enzyme (ACE) inhibitors. Enalapril is derived from the first ACE inhibitor captopril and has several advantages in terms of side effects

ACE inhibitors inhibit the angiotensin converting enzyme(ACE), a peptidase involved in the conversion of angiotensin-I to angiotensin-II. Angiotensin-II is an endogenous substance that binds to the receptors of the blood vessels and thus leads to vasoconstriction. The result is an increase in blood pressure. Enalapril prevents the formation of angiotensin II and thus causes the blood vessels to relax and blood pressure to fall. In addition, it develops effects on the heart that lead to an economization of the work of the heart.

After ingestion, enalapril is rapidly absorbed into the blood through the intestines to about two-thirds of its capacity. The highest levels of enalapril are reached after just one hour. The intake of enalapril is not hindered by food.

In the liver, the prodrug enalapril is converted into enalaprilate (hepatic ester hydrolysis). The highest levels of the active form are found in the blood after about four hours. Enalapril and enalaprilate are excreted via the kidneys with the urine.

Enalapril is used for

• non organ-related high blood pressure (essential hypertension)
• mild to moderate heart failure (NYHA II to III) after acute (2 to 9 days old) heart attack,
• Patients with non-diabetic glomerular nephropathy (creatinine clearance < 70 ml/min/1.73 m2 , protein excretion in urine > 1 g/day) - especially if arterial hypertension is present at the same time.
• kidney diseases associated with diabetes (glomerular diabetic nephropathy with microalbuminuria or macroproteinemia)
• following a heart attack (myocardial infarction) with consecutive heart failure
• Patients with an increased cardiovascular risk, e.g. manifest coronary heart disease), diabetes mellitus with at least one additional risk factor, circulatory disorders of the limbs (peripheral arterial occlusive disease) or a history of stroke.

It makes sense to start the therapy with enalapril with small doses at first and then increase these over several weeks until the desired maintenance dose is reached.

Enalapril causes analogous side effects to other ACE inhibitors (Graefe KH 2016), especially ACE inhibitors induced angioedema, urticaria and itching.

In individual cases have been described:

Normocomplementaemic urticarial vasculitis (Koregol S et al. 2015).

Use in combination with other antihypertensive agents that act on the renin-angiotensin-aldosterone system (RAAS) should only be used in special individual cases, e.g. aliskiren (renin antagonist) and Sartane such as candesartan, losartan or valsartan (angiotensin-II inhibitor).

The combined intake of enalapril and potassium-saving dehydrating agents (such as spironolactone, triamterene, amiloride) or potassium preparations can lead to greatly increased potassium blood levels.

The use of tricyclic antidepressants, neuroleptics and other anaesthetic drugs can also lead to an increased drop in blood pressure. The use of the mood stabilizer lithium should be monitored by blood level controls.

The use of non-steroidal anti-inflammatory drugs (such as ASA or ibuprofen) may reduce the effect of enalapril.

Allergies to enalapril, another ACE inhibitor.

History of angioneurotic edema

Dialysis Patients

Renal artery stenosis

during the last 6 months of pregnancy

with simultaneous intake of aliskiren (renin inhibitor)

Pregnancy

Enalapril should be discontinued during pregnancy. After the 3rd month of pregnancy severe damage to the unborn child may occur.

Breastfeeding: The use of enalapril is not recommended for nursing mothers.

1. Garcia-Pavia P et al (2007) Late-onset angioedema due to an angiotensin-converting enzyme inhibitor. Can J Cardiol 23:315-316.
2. Graefe KH et al. drugs with effects on the vascular system. In: Graefe KH et al (Eds) Pharmacology and Toxicology. Georg Thieme Publisher Stuttgart S.170-174
3. Koregol S et al (2015) Enalapril induced normocomplementemic urticarial vasculitis. Indian J Dermatol Venereol Leprol 81:73-74.