Nebivolol is a beta blocker used to treat high blood pressure and heart failure. As with other β-blockers, it is generally a less preferred treatment for high blood pressure. It may be used by itself or with other blood pressure medication. It is taken by mouth. Common side effects include dizziness, feeling tired, nausea, and headaches. Serious side effects may include heart failure and bronchospasm. Its use in pregnancy and breastfeeding is not recommended. It works by blocking β1-adrenergic receptors in the heart and dilating blood vessels. Nebivolol was patented in 1983 and came into medical use in 1997. It is available as a generic medication in the United Kingdom. In 2020, it was the 239th most commonly prescribed medication in the United States, with more than 1million prescriptions. Medical uses It is used to treat high blood pressure and heart failure. Nebivolol is used in the treatment of angina, to decrease the heart rate and contractile force. This is relevant in patients who need to decrease the oxygen demand of the heart so that the blood supplied from stenosed or constricted arteries is adequate. ACE inhibitors, angiotensin II receptor antagonists, calcium-channel blockers, and thiazide diuretics are generally preferred over beta blockers for the treatment of primary hypertension in the absence of co-morbidities. Pharmacology and biochemistry β1-selectivity Beta blockers help patients with cardiovascular disease by blocking β1 receptors, while many of the side-effects of these medications are caused by their blockade of β2 receptors. For this reason, beta blockers that selectively block β1 adrenergic receptors (termed cardioselective or β1-selective beta blockers) produce fewer adverse effects (for instance, bronchoconstriction) than those drugs that non-selectively block both β1 and β2 receptors. In a laboratory experiment conducted on biopsied heart tissue, nebivolol proved to be the most β1-selective of the β-blockers tested, being approximately 3.5 times more β1-selective than bisoprolol. However, the drug's receptor selectivity in humans is more complex and depends on the drug dose and the genetic profile of the patient taking the medication. The drug is highly cardioselective at 5 mg. In addition, at doses above 10 mg, nebivolol loses its cardioselectivity and blocks both β1 and β2 receptors, while the recommended starting dose of nebivolol is 5 mg, sufficient control of blood pressure may require doses up to 40 mg. Furthermore, nebivolol is also not cardioselective when taken by patients with a genetic makeup that makes them "poor metabolizers"