Bisoprolol is a drug and is used to treat tachycardia, angina pectoris, high blood pressure and coronary heart disease (CHD). Bisoprolol has an antagonistic effect on ß-adrenoreceptors (beta adrenoreceptors) and belongs to the group of beta blockers. Taking the drug can cause side effects such as tiredness, dizziness, and headache.
What is bisoprolol?
Bisoprolol belongs to the group of selective ß-adrenoreceptor blockers and has an antagonistic effect on ß1-adrenoreceptors. As a selective beta blocker, bisoprolol has a specific effect on the heart and has no effect on other organs.
Bisoprolol is medically referred to as a cardioselective drug. From a chemical point of view, bisoprolol is a phenol ether that exists as a racemic mixture. Bisoprolol is a chiral compound and the drug is used in a 1: 1 mixture of stereoisomers (R) and (S). The (S) form of the drug is the active stereoisomer and has a high binding affinity for ß1-adrenoreceptors. (S) -Bisoprolol displaces adrenaline from the binding site of the ß1-adrenoreceptor and acts as an antagonist.
The drug is used to treat angina pectoris, tachycardia, chronic heart failure and high blood pressure. The drug requires regular use. Suddenly stopping therapy leads to withdrawal symptoms and serious side effects.
Pharmacological effect on the body and organs
The beta blocker bisoprolol occupies ß1-adrenaline receptors and prevents adrenaline and noradrenaline from binding to the receptors. Norepinephrine is a neurotransmitter that is formed in the brain and in the adrenal cortex of humans. Adrenaline is a hormone produced in the human adrenal cortex. Adrenaline and noradrenaline differ in their chemical structure through a methyl group. In the case of adrenaline, a methyl group is substituted on the amino group. Noradrenaline and adrenaline bind to ß1-adrenergic receptors in the heart and lead to increased activity of the heart muscle. The heart rate increases by lowering the stimulus threshold in the heart. The pumping capacity of the heart is increased and the blood pressure is increased.
Bisoprolol displaces adrenaline and noradrenaline from the ß1 adrenal receptors and occupies the binding sites. As an antagonist, the drug weakens the effects of adrenaline and noradrenaline. As a result of the receptor binding and the reduced adrenaline and noradrenaline effect, the blood pressure is lowered and the irritation threshold is increased. The heart needs less energy and oxygen consumption is reduced. Overall, the heart muscle is relieved by bisoprolol. Medicine speaks of a negative inotropic effect that all beta blockers have.
The binding and effects of bisoprolol are long-lasting. The half-life in the blood is 10 to 11 hours. Bisoprolol is administered orally and about 90% is absorbed. The bioavailability is excellent at 90% and the maximum plasma concentration is reached approx. 3 hours after ingestion. The beta blocker is excreted renally and metabolized in the liver. The ratio between renal excretion and liver elimination is 50:50.
Due to the targeted effect of bisoprolol on the ß1-adrenoreceptor, the drug has a cardiospecific effect. Nevertheless, it can have a central nervous effect. Effects and side effects of bisoprolol on the central nervous system (CNS) are due to the lipophilic properties of the drug. Intrinsic sympathomimetic activity (ISA) has not been demonstrated.
Medical application & use for treatment & prevention
The beta blocker bisoprolol is used to treat arterial hypertension (high blood pressure), chronic heart failure, angina pectoris and tachycardia. Angina pectoris can be triggered by coronary heart disease (CHD). The beta blocker is often used for high blood pressure and thus serves to prevent serious heart diseases.
The treatment of arterial hypertension and angina pectoris is usually started with a dose of 5 mg bisoprolol per day. The dose depends on the severity of the findings. A daily dose of 2.5 mg is recommended for mild high blood pressure. If a dose of 5 mg bisoprolol is insufficient, an increase to 10 mg bisoprolol per day is recommended. The daily dose should only be above 10 mg in exceptional cases. The dosage should be increased gradually or reduced slowly if necessary. If the drug is suddenly stopped, withdrawal symptoms and severe side effects are the result. The withdrawal from bisoprolol is only possible by tapering off and must be accompanied by a doctor.
Bisoprolol must not be used in patients with bronchial asthma, bradycardia, diabetes mellitus and severe heart failure. Patients who apply MAO inhibitors should also refrain from taking the drug.
Risks & side effects
Taking bisoprolol can cause side effects. Common complaints are tiredness, exhaustion, sensory disturbances, dizziness and headache. Occasional side effects of the drug include depression, sleep disorders, mood swings, and confusion.
Furthermore, when taking the drug, blood circulation disorders, muscle weakness, skin rashes, joint diseases and itchy skin can occur. A disturbed heart function and a slowed heartbeat are also part of the symptoms. A drop in blood pressure from getting up quickly from a sitting or lying position is also an uncommon side effect.
Vomiting, constipation, diarrhea, abdominal pain and nausea are occasional side effects in the gastrointestinal area. Reactions such as increased blood lipid levels, increased perspiration, reduced tearing, weight gain and sexual listlessness occur rarely.
