Beta blockers, including metoprolol, may cause erectile dysfunction and may reduce sperm movement, based on published research cited in the labeling. Reduced sex drive and difficulty getting an erection have also been reported since the medicine came on the market, though how often is not known. Beta blockers are medications used to lower blood pressure and manage heart rhythms. See a list of the different types of beta blocker such as metoprolol, atenolol, and more. Beta-blockers work by blocking the effect of adrenaline on the heart, which slows the heart rate, softens the force of each beat, and lowers blood pressure. They are used for far more than blood pressure. Beta-blockers are a class of medication used to block the effects of stress hormones such as adrenaline on the heart. Beta blockers are medicines that lower blood pressure. They also may be called beta-adrenergic blocking agents. These medicines block the effects of the hormone epinephrine, also known as adrenaline. Beta blockers cause the heart to beat more slowly and with less force. This lowers blood pressure. Beta blockers are widely used for the treatment of hypertension. Beta blockers, also known as beta-adrenergic blocking agents, are a class of drugs that works by blocking the neurotransmitters norepinephrine and epinephrine from binding to receptors. There are three known types of beta receptors, known as beta 1 (β 1), beta 2 (β 2) and beta 3 (β 3). Beta-blockers treat a wide range of cardiovascular conditions, like high blood pressure. They slow down your heart rate and relax your blood vessels. There are 2 main types of beta blockers: Beta blockers usually come as tablets or capsules that you swallow. There are also eye drops for glaucoma. Not all beta blockers are listed here. If you cannot find your medicine, check the leaflet that comes with it, or ask your doctor or pharmacist. Beta blockers, also known as beta-adrenergic blocking agents, are drugs that block norepinephrine and epinephrine (adrenaline) from binding to beta receptors on nerves.