The active substance metoprolol is used for the therapy of heart diseases and high blood pressure. Furthermore, the drug can be used to prevent migraines.
What is metoprolol?
The active substance metoprolol is used for the therapy of heart diseases and high blood pressure. Metoprolol belongs to the drug group of beta-blockers. Thus, it is suitable for the treatment of coronary artery disease, tachycardic arrhythmias, and arterial hypertension (high blood pressure). Metoprolol was first marketed in the United States in 1978. Further patent claims led to the development of the drug as a succinate. It was approved in the USA in 1992. In the meantime, metoprolol is also available as an inexpensive generic drug. Metoprolol has the advantage of being well tolerated. However, overdosage of the drug should be avoided, as this can result in pronounced side effects. Due to its prescription nature, metoprolol can only be obtained from pharmacies upon presentation of a prescription.
Pharmacologic action
In the event of stress, the human organism releases the hormone adrenaline into the blood. Adrenaline is a stress hormone that reaches all organs after a short time. By docking to beta-adrenoreceptors, the hormone is able to emit stress signals. As a result, the respective organs adapt to the stress situation. In addition, the widening of the bronchial tubes takes place, which means that more oxygen is absorbed. Further processes are the reduction of the digestive function, a stronger blood circulation as well as a faster heartbeat. In this way, the human body receives more energy and oxygen. Sometimes, however, deviations of the system are also possible. The heart then beats faster, although it has not received a signal to do so. As a result, the organism is put under considerable strain, which in turn can cause damage to the blood vessels, the development of blood clots and cardiac arrhythmias. This is where metoprolol comes in. The active ingredient selectively blocks the adrenaline receptors located on the heart. In this way, the drug counteracts the docking of adrenaline so that it is no longer able to exert its effect. Thus, the heartbeat remains normal. When metoprolol is taken orally, almost all of the active substance is absorbed into the intestine. Even before reaching the site of action, however, the drug is largely broken down by the liver. Because metoprolol is rapidly excreted by the kidneys within 3.5 hours, it is usually administered in sustained-release tablets, which delay the release of the drug. The drug level within the organism thus achieves the same continuity for about 24 hours.
Medical application and use
The main indications for metoprolol are hypertension and cardiovascular disease. Furthermore, the beta-blocker is suitable for the treatment of heart disease associated with myocardial insufficiency. This includes, for example, stable angina pectoris that does not cause any symptoms. Also among the indications for metoprolol are cardiac arrhythmias associated with an excessively fast heartbeat. By slowing the heartbeat, the drug exerts a positive influence on the disorders. Metoprolol can also be administered to relieve the heart during treatment of an acute heart attack. Following a heart attack, the beta-blocker is used to prevent further symptoms. In this way, the risk of sudden cardiac death is reduced. However, metoprolol is not only used for the treatment of heart disease, but can also be used for the prophylaxis of migraine attacks. If the drug is taken at regular intervals, the extent and frequency of migraine attacks can be reduced. Metoprolol is used as a salt with succinic acid (succinate), fumaric acid (fumarate) or tartaric acid (tartrate). The drug is usually administered as a sustained-release tablet, from which the active ingredient is released with a delay. Other forms of administration include conventional tablets and injections. Metoprolol can also be administered in combination with calcium channel blockers or diuretics. The advantage of sustained-release tablets is that they only need to be taken once a day. For this purpose, the optimal dose of the active substance is determined by the physician.If metoprolol is to be discontinued, the dose must be reduced step by step to avoid the undesirable rebound phenomenon. This involves a reflex increase in blood pressure after sudden discontinuation of the drug.
Risks and side effects
About one to ten out of one hundred patients suffer side effects after taking metoprolol. These primarily include dizziness after standing up, fatigue, slowed heartbeat, headache, nausea, vomiting, and breathing problems after physical exertion. Other conceivable side effects may include cardiac arrhythmias, circulatory problems with loss of consciousness, worsening of heart muscle weakness, general malaise, lethargy, insomnia, constipation, diarrhea, flatulence, tingling of the skin, feeling of coldness in the limbs, allergic skin reactions, fatigue, and confusion. Even depression, nightmares or hallucinations are within the realm of possibility. If hypersensitivity to metoprolol or other beta-blockers is present, the patient must refrain from taking the drug. The same applies in the event of cardiogenic shock, inadequately treated myocardial insufficiency, conduction disorders to the heart, low blood pressure, circulatory disorders due to Raynaud’s syndrome or peripheral arterial occlusive disease, diseases of the adrenal medulla, pronounced asthma or disorders of the acid-base balance. Attention must also be paid to interactions with other medications. This is because the blood pressure-lowering effect is considerably enhanced by the simultaneous use of metoprolol and other blood pressure-lowering preparations. These include calcium channel blockers of the nifedipine type, ACE inhibitors, blood vessel dilating agents such as hydralazine or dihydralazine, and diuretics (dehydrating agents).
