Alprenolol

The non-selective beta blocker Alprenolol was developed in the late 1960s and is no longer on the market today. The active ingredient is called nonselective because it does not only act on the ß-adrenoreceptors in the body, which are directly responsible for controlling the heartbeat, but on all three known subgroups of the receptors that take on various functions in the body.

What is alprenolol

Alprenolol is a beta blocker that was patented in 1969 by the pharmaceutical company AB Hässle and brought onto the market. The preparation, which was primarily prescribed for the treatment of high blood pressure, is now no longer on the market.

In terms of its chemical structure, alprenolol has a similar structure to oxprenolol, which is why it is also assigned to the group of non-selective beta blockers. If alprenolol is administered in high doses, it has a stabilizing effect on the cell membrane; here, too, alprenolol is similar to the active ingredient oxprenolol.

The active ingredient is only partially liposoluble and has a plasma half-life of up to three hours after administration. The bioavailability of alprenolol is only relatively low at ten percent. The bioavailability describes the value with which a preparation is available unchanged in the circulation.

Pharmacological effect

Like all beta blockers, alprenolol is used to inhibit the stimulating effects of the hormones adrenaline and noradrenaline. However, because alprenolol does not specifically and exclusively targets the ß1 receptors, which are directly controlled by both heart strength and heart rate, alprenolol is called a non-selective beta blocker.

Rather, Alprenolol acts on all three subtypes of ß-adrenoceptors, which occur in the heart, in adipose tissue and in the smooth muscles in a very high density. All ß-receptors are stimulated by adrenaline. This is produced in the adrenal medulla and is called the stress hormone, which is increasingly released in the event of particular stress and stressful situations.

The result of this hormone release is an increase in heart rate, an increase in blood pressure, an expansion of the bronchi and an accelerated breakdown of fat in order to provide the body with energy. This mechanism, which played a vital role in the early days of human development, stresses the cardiovascular system in particular. Beta blockers like alprenolol block the causes of high blood pressure and a fast heart rate on a biochemical level.

Medical application & use

Beta blockers such as alprenolol are mainly prescribed for chronically high blood pressure. High blood pressure is used when the systolic blood pressure is consistently above a value of 140 mmHg; the limit for diastolic blood pressure is 90 mmHg.

The most common causes of high blood pressure are disorders of the cardiovascular system, the hormonal system and damage to the kidneys. Genetic factors can also play a role. This significantly increases the risk of children one day suffering from high blood pressure if this was already the case with their parents. In addition to diabetes and being very overweight, high blood pressure is an important risk factor for the development of arteriosclerosis, which in turn can cause severe damage to the cardiovascular system, such as heart attacks.

Other complaints for which preparations such as alprenolol are administered are coronary heart disease, heart attack therapy, heart failure and cardiac arrhythmias. In addition, there are a number of other diseases such as hyperthyroidism, anxiety or migraines, in which the preparation can provide relief in individual cases.

Risks & side effects

The active ingredient group ISA contained in Alprenolol leads to sleep disorders more often than ISA-free beta blockers. Otherwise, the same side effects can occur when taking alprenolol as with all beta blockers. The most common side effects include a slow heart rate, heart failure, or asthma attacks.

This side effect is also the reason why alprenolol should not be given to patients suffering from bronchial asthma. Heart failure, known as a disease in its own right, is the inability of the heart muscle to transport the amount of blood that the body needs into the atria without an increase in pressure.

Often other problems such as fatigue, peripheral circulatory disorders, depressive moods or erectile dysfunction can also occur. Conduction disorders in the heart can also occur as an undesirable effect of beta blockers. This is a relatively common form of cardiac arrhythmia.