Nebivolol is a β adrenergic receptor blocking agent. Nebivolol inhibits both β1 and β1 adrenergic receptors. Nebivolol lacks intrinsic sympathomimetic and membrane stabilizing activity at therapeutically relevant concentrations. At clinically relevant doses, Nebivolol does not demonstrate β1-adrenergic receptor blockade activity. Various metabolites, including glucuronides, contribute to beta-blocking activity.

Mode of Action of Nebivolol involved include:

• decreased heart rate
• decreased myocardia contractility
• diminution of tonic sympathetic outflow to the periphery from cerebral vasomotor centers
• suppression of renin activity and
• vasodilation and decreased peripheral vascular resistance

Pharmacokinetics: Nebivolol is metabolized by a number of routes, including glucuronidation and hydroxylation by CYP2D6. The active isomer (d-nebivolol) has an effective half-life of about 12 hours in CYP2D6 extensive metabolizers (most people), and 19 hours in poor metabolizers and exposure to d-nebivolol is substantially increased in poor metabolizers. This has less importance than usual, however, because the metabolites, including the hydroxyl metabolite and glucuronides (the predominant circulating metabolites), contribute to b blocking activity.

Absorption and Distribution: Absorption of Nebivolol is similar to an oral solution. Mean peak plasma nebivolol concentrations occur approximately 1.5 to 4 hours post-dosing in EMs and PMs. Food does not alter the pharmacokinetics of nebivolol. Nebivolol may be administered without regard to meals. The in vitro human plasma protein binding of nebivolol is approximately 98%, mostly to albumin, and is independent of nebivolol concentrations.

Metabolism and Excretion: Nebivolol is predominantly metabolized via direct glucuronidation of parent and to a lesser extent via N-dealkylation and oxidation via cytochrome P450 2D6. After a single oral administration of 14C-nebivolol, 38% of the dose was recovered in urine and 44% in feces for EMs and 67% in urine and 13% in feces for PMs.

Digoxin: Concomitant administration of Nebivolol (10 mg once daily) and digoxin (0.25 mg once daily) for 10 days in 14 healthy adult individuals resulted in no significant changes in the pharmacokinetics of digoxin or nebivolol.

Warfarin: Administration of Nebivolol (10 mg once daily for 10 days) led to no significant changes in the pharmacokinetics of nebivolol or R- or S-warfarin following a single 10 mg dose of warfarin. Similarly, nebivolol has no significant effects on the anticoagulant activity of warfarin, as assessed by Prothrombin time and INR profiles from 0 to 144 hours after a single 10 mg warfarin dose in 12 healthy adult volunteers. The starting dose should be reduced in patients with moderate hepatic impairment. No formal studies have been performed in patients with severe hepatic impairment and nebivolol should be contraindicated for these patients.

Nebivolol is indicated in-

• Hypertension
• Treatment of essential hypertension
• Chronic heart failure (CHF)
• Treatment of stable mild and moderate chronic heart failure in addition to standard therapies in elderly patients.

The dose of Nebivolol should be individualized to the needs of the patient. For most patients, the recommended starting dose is 5 mg once daily, with or without food, as monotherapy or in combination with other agents. For patients requiring further reduction in blood pressure, the dose can be increased at 2-week intervals up to 40 mg. A more frequent dosing regimen is unlikely to be beneficial.

Nebivolol is contraindicated in patients with severe bradycardia, heart block greater than first degree, cardiogenic shock, decompensated cardiac failure, sick sinus syndrome (unless a permanent pacemaker is in place), or severe hepatic impairment (Child-Pugh >B), and in patients who are hypersensitive to any component of this product.

Headache, nausea and bradycardia.

Abrupt Cessation of Therapy: Patients with coronary artery disease treated with Nebivolol should be advised against abrupt discontinuation of therapy. Severe exacerbation of angina and the occurrence of myocardial infarction and ventricular arrhythmias have been reported in patients with coronary artery disease following the abrupt discontinuation of therapy with β-blockers. Myocardial infarction and ventricular arrhythmias may occur with or without preceding exacerbation of the angina pectoris. Even patients without overt coronary artery disease should be cautioned against interruption or abrupt discontinuation of therapy. As with other β-blockers, when discontinuation of Nebivolol is planned, patients should be carefully observed and advised to minimize physical activity. Nebivolol should be tapered over 1 to 2 weeks when possible. If the angina worsens or acute coronary insufficiency develops, it is recommended that Nebivolol be promptly reinstituted, at least temporarily.

Cardiac Failure: Sympathetic stimulation is a vital component supporting circulatory function in the setting of congestive heart failure, and (β-blockade may result in further depression of myocardial contractility and precipitate more severe failure. In patients who have compensated congestive heart failure, Nebivolol should be administered cautiously. If heart failure worsens, discontinuation of Nebivolol should be considered.

Angina and Acute Myocardial Infarction: Nebivolol was not studied in patients with angina pectoris or who had a recent Ml.

Bronchospastic Diseases: In general, patients with bronchospastic diseases should not receive (3-blockers.

Anesthesia and Major Surgery: If Nebivolol is to be continued perioperatively, patients should be closely monitored when anesthetic agents which depress myocardial function, such as ether, cyclopropane, and trichloroethylene, are used. If β-blocking therapy is withdrawn prior to major surgery, the impaired ability of the heart to respond to reflex adrenergic stimuli may augment the risks of general anesthesia and surgical procedures. The β-blocking effects of Nebivolol can be reversed by β-agonists, e.g., dobutamine or isoproterenol. However, such patients may be subject to protracted severe hypotension. Additionally, difficulty in restarting and maintaining the heartbeat has been reported with (β-blockers).

Diabetes and Hypoglycemia: β-blockers may mask some of the manifestations of hypoglycemia, particularly tachycardia. Nonselective β-blockers may potentiate insulin-induced hypoglycemia and delay recovery of serum glucose levels. It is not known whether nebivolol has these effects. Patients subject to spontaneous hypoglycemia, or diabetic patients receiving insulin or oral hypoglycemic agents, should be advised about these possibilities and nebivolol should be used with caution.

Thyrotoxicosis: β-blockers may mask clinical signs of hyperthyroidism, such as tachycardia. Abrupt withdrawal of β-blockers may be followed by an exacerbation of the symptoms of hyperthyroidism or may precipitate a thyroid storm.

Peripheral Vascular Disease: β-blockers can precipitate or aggravate symptoms of arterial insufficiency in patients with peripheral vascular disease. Caution should be exercised in these patients.

Non-dihydropyridine Calcium Channel Blockers: Because of significant negative inotropic and chronotropic effects in patients treated with β-blockers and calcium channel blockers of the verapamil and diltiazem type, caution should be used in patients treated concomitantly with these agents and ECG and blood pressure should be monitored.

Use in Special Populations

Impaired Renal Function: Nebivolol should be used with caution in patients with severe renal impairment because of decreased renal clearance. Nebivolol has not been studied in patients receiving dialysis.

Impaired Hepatic Function: Nebivolol should be used with caution in patients with moderate hepatic impairment because of decreased metabolism. Since Nebivolol has not been studied in patients with severe hepatic impairment, Nebivolol is contraindicated in this population. 

Risk of Anaphylactic Reactions: While taking β-blockers, patients with a history of severe anaphylactic reactions to a variety of allergens may be more reactive to repeated challenges either accidental, diagnostic, or therapeutic. Such patients may be unresponsive to the usual doses of epinephrine used to treat allergic reactions.