Ace inhibitors

Short name for competitive inhibitors of the angiotensin-converting enzyme (ACE). ACE inhibitors are drugs that are used primarily in the therapy of arterial hypertension and chronic heart failure.

When the blood pressure drops, the so-called "RAAS"(renin-angiotensin-aldosterone system) is activated. This is a cascade-like, interacting enzyme-hormone system that regulates blood pressure in a highly differentiated manner via various mechanisms (increase in blood volume, vasoconstrictive effect). The system is activated by the release of renin in the kidneys, a protein-splitting enzyme that triggers a whole series of reactions. One of the reactions is the conversion of angiotensin I into the peptide angiotensin II. This reaction is catalysed by the angiotensin converting enzyme (ACE).

ACE inhibitors block ACE, which means that angiotensin II, which is important for the regulation of blood pressure, is not produced or is produced in a reduced form. ACE inhibitors block this enzyme, which means that angiotensin II, which is important for the regulation of blood pressure, is not produced or is produced in a reduced form.

Nephroprotective effect ACE inhibitors: they lower the tone of the afferent arterioles in the glomerulum more than in afferent arterioles. This results in a reduction of the gelomerular filtration pressure.

The main agents used in therapy are captopril, enalapril, lisinopril and ramipril.

The inhibition of the angiotensin converting enzyme ( ACE) leads to a reduced angiotensin II production from angiotensin I. Furthermore, the degradation of bradykinin is inhibited and leads to its accumulation (see side effects).

In kidney diseases such as diabetic nephropathy, ACE inhibitors lead to reduced protein excretion (proteinuria) and prevent disease progression (nephroprotection).

Myocardial infarction: Patients with myocardial infarction always benefit from therapy with ACE inhibitors. Treatment should begin between the 2nd and 7th day after the infarction event and should always be continued for an indefinite period of time if left ventricular dysfunction is detected.

At the start of therapy, a sharp drop in blood pressure (in 1% of patients) can occur. This occurs when there is a high activity of the renin-aldosterone system (Cave: Patients must be monitored initially for several hours). This phenomenon of the first dose can be prevented with an appropriate therapy.

As monotherapeutics or in combination with diuretics or calcium antagonists for the treatment of hypertensive heart disease. Also used in chronic heart failure and diabetic nephropathy.

Dry cough, asthmoid complaints (the side effects are associated, among other things, with an accumulation of bradykinin and substance P; no tolerance phenomena are to be expected here, these side effects often lead to discontinuation of therapy) The cough can be suppressed by sodium cromoglicate.

Hepatotoxic side effects (1%); increase in liver-specific enzymes; signs of cholestasis Throm

Reversible increase in serum creatinine

Blood picture changes (leukopenia, neutropenia, thrombocytopenia)

Furthermore:

• hypotension, acute renal failure, hyperkalemia, urticarial exanthema (0.1-1% of cases) and urticaria (0.01-0.1%).
• central nervous complaints such as headaches, dizziness and dizziness
• gastrointestinal disorders (1-3%), upper abdominal pain (reports of isolated visceral angioedema are available)
• Hyperkalemia (clinically relevant hyperkalemia occurs in < 10% of cases. Cave: potassium-retarding diuretics!)
• Pruritus: It is not uncommon for ACE inhibitors to cause a possibly late-manifested, extremely therapy-resistant pruritus (often accompanied by physical urticaria).
• Angioedema: Important from a dermatological/allergological point of view is the angioedema acquired through the use of ACE inhibitors (0.01-0.1%). These side effects are mainly seen in patients with a deficiency of aminopeptidase P (this enzyme, together with ACE, is responsible for the breakdown of bradykinin). ACE-induced angioedema is best treated with 30mg Icatibant (antagonist of the bradykinin B2 receptor).
• For further side effects see under the individual preparations.

ACE inhibitors intensify the haematological side effects of immunosuppressive drugs (immunosuppressants, cytostatics and glucocorticoids)

Examples of active ingredients and preparations from the group of ACE inhibitors:

• Benazepril (Cibacen, generic products)
• Captopril (Lopirin, Tensobon, generic drugs)
• Cilazapril (dynorm)
• Enalapril (Xanef, Pres, generic drugs)
• Fosinopril (Fosinorm, Dynacil)
• Imidapril (Tanatril)
• Lisinopril (Acerbon, Coric, generic products)
• Moexipril (Fempress)
• Perindopril (Coversum, Preterax)
• Quinapril (Accupro, generic products)
• Ramipril (Delix, Vesdil, generic products)
• Spirapril (Quadropril)
• Trandolapril (Gopten, Udrik).

In Germany, about 20% of the population and every second person over 55 years of age takes drugs to treat high blood pressure. About 35% of hypertension patients are treated with an ACE inhibitor in monotherapy and about 55% in combination with another blood pressure lowering drug.

In the case of angioedema triggered by ACEI, switching to an AT1 receptor blocker is not a solution to the problem, as these can also trigger angioedema (although less frequently than ACEI).

1. Graefe KH et al. Pharmak with effects on the vascular system. In: Graefe KH et al. (Eds) Pharmacology and Toxicology. Georg Thieme Publisher Stuttgart S.172-173
2. Wedi B et al.(2011) Pharmacoprophylaxis and concomitant medication for specific immunotherapy. Dermatologist 62: 663-670