The active substance pindolol belongs to the group of beta blockers. It is used, among other things, for the therapy of high blood pressure.
What is pindolol?
The active substance pindolol belongs to the group of beta-blockers. It is used, among other things, for the therapy of high blood pressure. Pindolol is a nonselective beta blocker. It is also a class II antiarrhythmic agent. The drug dilates the blood vessels and lowers blood pressure. In Europe, the drug has been used since 1969 and is usually administered in tablet form. Pindolol is also used in rescue medicine.
Pharmacological action
Pindolol is a non-selective beta-blocker. This means that after ingestion, the substance can exert its effect on the one hand at the beta-1 receptors of the heart and on the other hand at the other beta receptors. The beta receptors serve as binding sites for sympathetic fibers belonging to the autonomic nervous system. They are normally activated by the neurotransmitters adrenaline and noradrenaline, which are produced by the body itself. However, the body’s own neurotransmitters are displaced at the receptors by pindolol, which in turn has a suppressive effect on their effects. Pindolol causes a lowering of blood pressure at the beta-1 receptors, which belong to the heart. This leads to a reduction in the volume of the heartbeat. Due to this effect, there is a relief of the heart pumping function. In addition, the number of heartbeats decreases, which results in the restoration of normal rhythm. As a drug, Pindolol is also suitable for local treatment of the eye to lower intraocular pressure. In this procedure, the drug is administered in the form of eye drops. However, it is not yet known how the blockade of the beta receptors produces this positive effect. Some physicians assume that the production of aqueous humor inside the eye is reduced by pindolol. Furthermore, the aqueous humor that is already present drains better. Pindolol is mainly administered orally or intravenously. The bioavailability of the drug is 95 percent, while plasma protein binding is 60 percent. Metabolism occurs via the liver. In this process, pindolol achieves a plasma half-life of four hours on average. Subsequently, 40 percent of the substance is excreted via the kidneys.
Medical use and application
The most important area of use of pindolol is high blood pressure. In this case, the aim is to reduce excessive blood pressure levels and normalize blood pressure permanently. Another indication is heart pain in the context of an angina pectoris attack and coronary heart disease (CHD). Thus, pindolol is suitable for reducing cardiac stress. In addition, rapid cardiac arrhythmias are restored to normal by pindolol. Through the administration of eye drops, Pindolol also serves to lower elevated intraocular pressure, which is evident in glaucoma (glaucoma). This is especially true in the case of chronic open-angle glaucoma, which is a special form of glaucoma. In emergency medicine, pindolol is used to treat supraventicular tachycardia (SVT). In this cardiac arrhythmia, which can manifest itself after the ingestion of nitroglycerin, there is an excessively high pulse rate of more than one hundred beats per minute. Pindolol is commercially available in tablet form. The drug is taken one to three times a day, regardless of meals.
Risks and side effects
Administering pindolol may cause unwanted side effects in patients, but these are not inevitable. In most cases, affected individuals suffer from diarrhea, constipation, nausea, vomiting, fatigue, drowsiness, nervousness, sweating, depression, headache, sleep disturbances, and allergic skin reactions such as itching and redness. Occasionally, a decrease in tear flow, conjunctivitis, slow heartbeat, cold sensations in the arms and legs, dry mouth, muscle cramps, and muscle weakness may also occur. Rarely, increased heart muscle weakness or circulatory problems, potency weakness, difficulty breathing, increased drop in blood pressure, worsening of diabetes mellitus (diabetes), and fainting spells are seen. If a patient suffers from impaired kidney function, the symptoms may additionally worsen. If certain contraindications are present, Pindolol must not be used.These contraindications include severe cardiac conduction system disease, severe myocardial insufficiency, cardiovascular shock, a slowed heartbeat of less than 50 beats per minute, and a recent heart attack. Other contraindications include low blood pressure, bronchial asthma, COPD, hyperacidity of the metabolism, or nutritional disorders of the cornea. In addition, the administration of pindolol must be carefully considered if the functions of the liver and kidneys are impaired, high physical stress or strict fasting has occurred, a pheochromocytoma is present or the patient suffers from severe psoriasis. The same applies to pregnancy and lactation. Likewise, careful consideration of the administration of pindolol in children is required. Interactions with other medical agents are also possible with pindolol. For example, the simultaneous administration of insulin or other substances used in diabetes therapy may increase or prolong their effect. With simultaneous administration of pindolol and tricyclic antidepressants, narcotics, diuretics, phenothiazines, barbiturates as well as vasodilators there is a risk of a drop in blood pressure. The patient’s heart rate may drop if pindolol is administered concomitantly with cardiac glycosides or drugs that act in the brain, such as clonidine, methyldopa, reserpine, and guanfacine. If clonidine is abruptly discontinued and pindolol is taken at the same time, a very large increase in blood pressure is conceivable. Simultaneous administration of non-steroidal anti-inflammatory drugs such as indomethacin and the beta-blocker risks weakening the blood pressure-lowering effect of pindolol. Furthermore, pindolol reduces the effect of adrenaline. In such cases, it is necessary to increase the dose of epinephrine.
