Zenebi

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 > 70 years.

For oral administration

Posology

Hypertension

Adults

The dose is 5 mg (one 5 mg tablet or two 2.5 mg tablets) daily, preferably at the same time of the day.

The blood pressure lowering effect becomes evident after 1-2 weeks of treatment. Occasionally, the optimal effect is reached only after 4 weeks.

Combination with other antihypertensive agents

Beta-blockers can be used alone or concomitantly with other antihypertensive agents. To date, an additional antihypertensive effect has been observed only when Zenebi is combined with hydrochlorothiazide 12.5-25 mg.

Patients with renal insufficiency

In patients with renal insufficiency, the recommended starting dose is 2.5 mg daily. If needed, the daily dose may be increased to 5 mg.

Patients with hepatic insufficiency

Data in patients with hepatic insufficiency or impaired liver function are limited. Therefore the use of Zenebi in these patients is contraindicated.

Elderly

In patients over 65 years, the recommended starting dose is 2.5 mg daily. If needed, the daily dose may be increased to 5 mg. However, in view of the limited experience in patients above 75 years, caution must be exercised and these patients monitored closely.

Paediatric population

No data are available. Zenebi should therefore not be used in children and adolescents.

Chronic heart failure (CHF)

The treatment of stable chronic heart failure has to be initiated with a gradual uptitration of dosage until the optimal individual maintenance dose is reached.

Patients should have stable chronic heart failure without acute failure during the past six weeks. It is recommended that the treating physician should be experienced in the management of chronic heart failure.

For those patients receiving cardiovascular medicinal therapy including diuretics and/or digoxin and/or ACE inhibitors and/or angiotensin II antagonists, dosing of these medicines should be stabilised during the past two weeks prior to initiation of Zenebi tablets treatment.

The initial uptitration should be done according to the following steps at 1-2 weekly intervals based on patient tolerability:

1.25 mg Zenebi, to be increased to 2.5 mg Zenebi once daily, then to 5 mg once daily and then to 10 mg once daily.

The maximum recommended dose is 10 mg Zenebi once daily.

Initiation of therapy and every dose increase should be done under the supervision of an experienced physician over a period of at least 2 hours to ensure that the clinical status (especially as regards blood pressure, heart rate, conduction disturbances, signs of worsening of heart failure) remains stable.

Occurrence of adverse events may prevent all patients being treated with the maximum recommended dose. If necessary, the dose reached can also be decreased step by step and reintroduced as appropriate.

During the titration phase, in case of worsening of the heart failure or intolerance, it is recommended first to reduce the dose of Zenebi, or to stop it immediately if necessary (in case of severe hypotension, worsening of heart failure with acute pulmonary oedema, cardiogenic shock, symptomatic bradycardia or AV block).

Treatment of stable chronic heart failure with Zenebi is generally a long-term treatment.

The treatment with Zenebi is not recommended to be stopped abruptly since this might lead to a transitory worsening of heart failure. If discontinuation is necessary, the dose should be gradually decreased divided into halves weekly.

Patients with renal insufficiency

No dose adjustment is required in mild to moderate renal insufficiency since uptitration to the maximum tolerated dose is individually adjusted. There is no experience in patients with severe renal insufficiency (serum creatinine > 250µmol/L). Therefore, the use of Zenebi in these patients is not recommended.

Patients with hepatic insufficiency

Data in patients with hepatic insufficiency are limited. Therefore the use of Zenebi tablets in these patients is contra-indicated.

Elderly

No dose adjustment is required since uptitration to the maximum tolerated dose is individually adjusted.

Children and adolescents

No studies have been conducted in children and adolescents. Therefore, use in children and adolescents is not recommended.

Method of administration

The tablets should be taken with some water. They may be taken with meals.

- Hypersensitivity to the active substance or to any of the excipients

- Liver insufficiency or liver function impairment

- Acute heart failure, cardiogenic shock or episodes of heart failure decompensation requiring intravenous inotropic therapy.

In addition, as with other beta-blocking agents, Zenebi are contra-indicated in:

- sick sinus syndrome, including sino-atrial block,

- second and third degree heart block (without a pacemaker),

- history of bronchospasm and bronchial asthma,

- untreated phaeochromocytoma,

- metabolic acidosis,

- bradycardia (heart rate < 60 bpm prior to start therapy),

- hypotension (systolic blood pressure < 90 mmHg),

- severe peripheral circulatory disturbances.

See also 4.8 Undesirable effects.

The following warnings and precautions apply to beta-adrenergic antagonists in general.

Anaesthesia

Continuation of beta-blockade reduces the risk of arrhythmias during induction and intubation. If beta-blockade is interrupted in preparation for surgery, the beta-adrenergic antagonist should be discontinued at least 24 hours beforehand.

Caution should be observed with certain anaesthetics that cause myocardial depression. The patient can be protected against vagal reactions by intravenous administration of atropine.

Cardiovascular

In general, beta-adrenergic antagonists should not be used in patients with untreated congestive heart failure (CHF), unless their condition has been stabilised.

In patients with ischaemic heart disease, treatment with a beta-adrenergic antagonist should be discontinued gradually, i.e. over 1-2 weeks. If necessary replacement therapy should be initiated at the same time, to prevent exacerbation of angina pectoris.

Beta-adrenergic antagonists may induce bradycardia: if the pulse rate drops below 50-55 bpm at rest and/or the patient experiences symptoms that are suggestive of bradycardia, the dosage should be reduced.

Beta-adrenergic antagonists should be used with caution:

- in patients with peripheral circulatory disorders (Raynaud's disease or syndrome or intermittent claudication), as aggravation of these disorders may occur;

- in patients with first degree heart block, because of the negative effect of beta-blockers on conduction time;

- in patients with Prinzmetal's angina due to unopposed alphareceptor mediated coronary artery vasoconstriction: beta-adrenergic antagonists may increase the number and duration of anginal attacks.

Metabolic/Endocrinological

Zenebi does not affect glucose levels in diabetic patients. Care should be taken in diabetic patients however, as Zenebi may mask certain symptoms of hypoglycaemia (tachycardia, palpitations).

Beta-adrenergic blocking agents may mask tachycardic symptoms in hyperthyroidism. Abrupt withdrawal may intensify symptoms.

Respiratory

In patients with chronic obstructive pulmonary disorders, beta-adrenergic antagonists should be used with caution as airway constriction may be aggravated.

Other

Patients with a history of psoriasis should take beta-adrenergic antagonists only after careful consideration.

Beta-adrenergic antagonists may increase the sensitivity to allergens and the severity of anaphylactic reactions.

The initiation of Chronic Heart Failure treatment with Zenebi necessitates regular monitoring.

This medicinal product contains lactose. Patients with rare hereditary problems of galactose intolerance, the Lapp-lactase deficiency or glucose-galactose malabsorption should not take this medicinal product.

Zenebi has minor influence on the ability to drive and use machines. Pharmacodynamic studies have shown that Zenebi does not affect psychomotor function. When driving vehicles or operating machines it should be taken into account that dizziness and fatigue may occasionally occur.

The following warnings and precautions apply to beta-adrenergic antagonists in general.

Anaesthesia

Continuation of beta-blockade reduces the risk of arrhythmias during induction and intubation. If beta-blockade is interrupted in preparation for surgery, the beta-adrenergic antagonist should be discontinued at least 24 hours beforehand.

Caution should be observed with certain anaesthetics that cause myocardial depression. The patient can be protected against vagal reactions by intravenous administration of atropine.

Cardiovascular

In general, beta-adrenergic antagonists should not be used in patients with untreated congestive heart failure (CHF), unless their condition has been stabilised.

In patients with ischaemic heart disease, treatment with a beta-adrenergic antagonist should be discontinued gradually, i.e. over 1-2 weeks. If necessary replacement therapy should be initiated at the same time, to prevent exacerbation of angina pectoris.

Beta-adrenergic antagonists may induce bradycardia: if the pulse rate drops below 50-55 bpm at rest and/or the patient experiences symptoms that are suggestive of bradycardia, the dosage should be reduced.

Beta-adrenergic antagonists should be used with caution:

- in patients with peripheral circulatory disorders (Raynaud's disease or syndrome or intermittent claudication), as aggravation of these disorders may occur;

- in patients with first degree heart block, because of the negative effect of beta-blockers on conduction time;

- in patients with Prinzmetal's angina due to unopposed alphareceptor mediated coronary artery vasoconstriction: beta-adrenergic antagonists may increase the number and duration of anginal attacks.

Metabolic/Endocrinological

Zenebi does not affect glucose levels in diabetic patients. Care should be taken in diabetic patients however, as Zenebi may mask certain symptoms of hypoglycaemia (tachycardia, palpitations).

Beta-adrenergic blocking agents may mask tachycardic symptoms in hyperthyroidism. Abrupt withdrawal may intensify symptoms.

Respiratory

In patients with chronic obstructive pulmonary disorders, beta-adrenergic antagonists should be used with caution as airway constriction may be aggravated.

Other

Patients with a history of psoriasis should take beta-adrenergic antagonists only after careful consideration.

Beta-adrenergic antagonists may increase the sensitivity to allergens and the severity of anaphylactic reactions.

The initiation of Chronic Heart Failure treatment with Zenebi necessitates regular monitoring.

This medicinal product contains lactose. Patients with rare hereditary problems of galactose intolerance, the Lapp-lactase deficiency or glucose-galactose malabsorption should not take this medicinal product.

Pharmacodynamic interactions

The following interactions apply to beta-adrenergic antagonists in general.

Combinations not recommended

Class I antiarrhythmics (quinidine, hydroquinidine, cibenzoline, flecainide, disopyramide, lidocaine, mexiletine, propafenone)

Effect on atrio-ventricular conduction time may be potentiated and negative inotropic effect increased.

Calcium channel antagonists of verapamil/diltiazem type:

Negative influence on contractility and atrio-ventricular conduction. Intravenous administration of verapamil in patients with β-blocker treatment may lead to profound hypotension and atrio-ventricular block.

Centrally-acting antihypertensives (clonidine, guanfacin, moxonidine, methyldopa, rilmenidine): Concomitant use of centrally acting antihypertensive medicinal products may worsen heart failure by a decrease in the central sympathetic tonus (reduction of heart rate and cardiac output, vasodilation). Abrupt withdrawal, particularly if prior to beta-blocker discontinuation, may increase risk of “rebound hypertension”.

Combinations to be used with caution

Class III antiarrhythmic substances (Amiodarone):

Effect on atrio-ventricular conduction time may be potentiated.

Anaesthetics - volatile halogenated:

Concomitant use of beta-adrenergic antagonists and anaesthetics may attenuate reflex tachycardia and increase the risk of hypotension. As a general rule, avoid sudden withdrawal of beta-blocker treatment. The anaesthesiologist should be informed when the patient is receiving Zenebi tablets.

Insulin and oral antidiabetic substances:

Although Zenebi does not affect glucose level, concomitant use may mask certain symptoms of hypoglycaemia (palpitations, tachycardia).

Baclofen (antispastic agent), amifostine (antineoplastic adjunct):

Concomitant use with antihypertensives is likely to increase the fall in blood pressure, therefore the dosage of the antihypertensive medicinal products should be adjusted accordingly.

Combinations to be considered

Digitalis glycosides:

Concomitant use may increase atrio-ventricular conduction time. Clinical trials with Zenebi have not shown any clinical evidence of an interaction. Zenebi does not influence the kinetics of digoxin.

Calcium antagonists of the dihydropyridine type (amlodipine, felodipine, lacidipine, nifedipine, nicardipine, nimodipine, nitrendipine):

Concomitant use may increase the risk of hypotension, and an increase in the risk of a further deterioration of the ventricular pump function in patients with heart failure cannot be excluded.

Antipsychotics, antidepressants (tricyclics, barbiturates and phenothiazines):

Concomitant use may enhance the hypothensive effect of the beta-blockers (additive effect).

Non steroidal anti-inflammatory drugs (NSAID):

No effect on the blood pressure lowering effect of Zenebi.

Sympathicomimetic agents:

Concomitant use may counteract the effect of beta-adrenergic antagonists. Beta-adrenergic agents may lead to unopposed alpha-adrenergic activity of sympathicomimetic agents with both alpha- and beta-adrenergic effects (risk of hypertension, severe bradycardia and heart block).

Pharmacokinetic interactions

As Zenebi metabolism involves the CYP2D6 isoenzyme, co-administration with substances inhibiting this enzyme, especially paroxetine, fluoxetine, thioridazine and quinidine may lead to increased plasma levels of Zenebi associated with an increased risk of excessive bradycardia and adverse events.

Co-administration of cimetidine increased the plasma levels of Zenebi, without changing the clinical effect. Co-administration of ranitidine did not affect the pharmacokinetics of Zenebi. Provided Zenebi tablets are taken with the meal, and an antacid between meals, the two treatments can be co-prescribed.

Combining Zenebi with nicardipine slightly increased the plasma levels of both active substances, without changing the clinical effect. Co-administration of alcohol, furosemide or hydrochlorothiazide did not affect the pharmacokinetics of Zenebi. Zenebi does not affect the pharmacokinetics and pharmacodynamics of warfarin.

Pregnancy

Zenebi has pharmacological effects that may cause harmful effects on pregnancy and/or the foetus/newborn. In general, beta-adrenoceptor blockers reduce placental perfusion, which has been associated with growth retardation, intrauterine death, abortion or early labour. Adverse effects (e.g. hypoglycaemia and bradycardia) may occur in the foetus and newborn infant. If treatment with beta-adrenoceptor blockers is necessary, beta₁-selective adrenoceptor blockers are preferable.

Zenebi should not be used during pregnancy unless clearly necessary. If treatment with Zenebi is considered necessary, the uteroplacental blood flow and the foetal growth should be monitored. In case of harmful effects on pregnancy or the foetus alternative treatment should be considered. The newborn infant must be closely monitored. Symptoms of hypoglycaemia and bradycardia are generally to be expected within the first 3 days.

Breast-feeding

Animal studies have shown that Zenebi is excreted in breast milk. It is not known whether this medicine is excreted in human milk. Most beta-blockers, particularly lipophilic compounds like Zenebi and its active metabolites, pass into breast milk although to a variable extent. Therefore, breastfeeding is not recommended during administration of Zenebi.

Zenebi has minor influence on the ability to drive and use machines. Pharmacodynamic studies have shown that Zenebi does not affect psychomotor function. When driving vehicles or operating machines it should be taken into account that dizziness and fatigue may occasionally occur.

Adverse reactions are listed separately for hypertension and CHF because of differences in the background diseases.

Hypertension

The adverse reactions reported, which are in most of the cases of mild to moderate intensity, are tabulated below, classified by system organ class and ordered by frequency:

The following adverse reactions have also been reported with some beta adrenergic antagonists: hallucinations, psychoses, confusion, cold/cyanotic extremities, Raynaud phenomenon, dry eyes, and oculo-mucocutaneous toxicity of the practolol-type.

Chronic heart failure

Data on adverse reactions in CHF patients are available from one placebo-controlled clinical trial involving 1067 patients taking Zenebi and 1061 patients taking placebo. In this study, a total of 449 Zenebi patients (42.1%) reported at least possibly causally related adverse reactions compared to 334 placebo patients (31.5%). The most commonly reported adverse reactions in Zenebi patients were bradycardia and dizziness, both occurring in approximately 11% of patients. The corresponding frequencies among placebo patients were approximately 2% and 7%, respectively.

The following incidences were reported for adverse reactions (at least possibly substance-related) which are considered specifically relevant in the treatment of chronic heart failure:

- Aggravation of cardiac failure occurred in 5.8 % of Zenebi patients compared to 5.2% of placebo patients.

- Postural hypotension was reported in 2.1% of Zenebi patients compared to 1.0% of placebo patients.

- Intolerance to the substance occurred in 1.6% of Zenebi patients compared to 0.8% of placebo patients.

- First degree atrio-ventricular block occurred in 1.4% of Zenebi patients compared to 0.9% of placebo patients.

- Oedema of the lower limb were reported by 1.0% of Zenebi patients compared to 0.2% of placebo patients.

Reporting of suspected adverse reactions:

Reporting suspected adverse reactions after authorisation of the medicinal product is mportant. It allows continued monitoring of the benefit/risk balance of the medicinal product. Healthcare professionals are asked to report any suspected adverse reactions via www.mhra.gov.uk/yellowcard

No data are available on overdosage with Zenebi.

Symptoms

Symptoms of overdosage with beta-blockers are: bradycardia, hypotension, bronchospasm and acute cardiac insufficiency.

Treatment

In case of overdosage or hypersensitivity, the patient should be kept under close supervision and be treated in an intensive care ward. Blood glucose levels should be checked. Absorption of any active substance residues still present in the gastro-intestinal tract can be prevented by gastric lavage and the administration of activated charcoal and a laxative. Artificial respiration may be required. Bradycardia or extensive vagal reactions should be treated by administering atropine or methylatropine. Hypotension and shock should be treated with plasma/plasma substitutes and, if necessary, catecholamines. The beta-blocking effect can be counteracted by slow intravenous administration of isoprenaline hydrochloride, starting with a dose of approximately 5 µg/minute, or dobutamine, starting with a dose of 2.5 µg/minute, until the required effect has been obtained. In refractory cases isoprenaline can be combined with dopamine. If this does not produce the desired effect either, intravenous administration of glucagon 50-100 µg/kg intravenous may be considered. If required, the injection should be repeated within one hour, to be followed -if required- by an intravenous infusion of glucagon 70 µg/kg/h. In extreme cases of treatment-resistant bradycardia, a pacemaker may be inserted.

Pharmacotherapeutic group: Beta blocking agents, selective; ATC code: C07AB12

Zenebi is a racemate of two enantiomers, SRRR-Zenebi (or d-Zenebi) and RSSS-Zenebi (or l-Zenebi). It combines two pharmacological activities:

- It is a competitive and selective beta-receptor antagonist: this effect is attributed to the SRRR-enatiomer (d-enantiomer).

- It has mild vasodilating properties due to an interaction with the L-arginine/nitric oxide pathway.

Single and repeated doses of Zenebi reduce heart rate and blood pressure at rest and during exercise, both in normotensive subjects and in hypertensive patients. The antihypertensive effect is maintained during chronic treatment.

At therapeutic doses, Zenebi is devoid of alpha-adrenergic antagonism.

During acute and chronic treatment with Zenebi in hypertensive patients systemic vascular resistance is decreased. Despite heart rate reduction, reduction in cardiac output during rest and exercise may be limited due to an increase in stroke volume. The clinical relevance of these haemodynamic differences as compared to other beta1 receptor antagonists has not been fully established.

In hypertensive patients, Zenebi increases the NO-mediated vascular response to acetylcholine (ACh) which is reduced in patients with endothelial dysfunction.

In a mortality-morbidity, placebo-controlled trial performed in 2128 patients > 70 years (median age 75.2 years) with stable chronic heart failure with or without impaired left ventricular ejection fraction (mean LVEF: 36 ± 12.3%, with the following distribution: LVEF less than 35% in 56% of patients, LVEF between 35% and 45% in 25% of patients and LVEF greater than 45% in 19% of patients) followed for a mean time of 20 months, Zenebi, on top of standard therapy, significantly prolonged the time to occurrence of deaths or hospitalisations for cardiovascular reasons (primary end-point for efficacy) with a relative risk reduction of 14% (absolute reduction: 4.2%). This risk reduction developed after 6 months of treatment and was maintained for all treatment duration (median duration: 18 months). The effect of Zenebi was independent from age, gender, or left ventricular ejection fraction of the population on study. The benefit on all cause mortality did not reach statistical significance in comparison to placebo (absolute reduction: 2.3%).

A decrease in sudden death was observed in Zenebi treated patients (4.1% vs 6.6%, relative reduction of 38%).

In vitro and in vivo experiments in animals showed that Zenebi has no intrinsic sympathicomimetic activity.

In vitro and in vivo experiments in animals showed that at pharmacological doses Zenebi has no membrane stabilising action.

In healthy volunteers, Zenebi has no significant effect on maximal exercise capacity or endurance.

Both Zenebi enantiomers are rapidly absorbed after oral administration. The absorption of Zenebi is not affected by food; Zenebi can be given with or without meals.

Zenebi is extensively metabolised, partly to active hydroxy-metabolites. Nebivol is metabolised via alicyclic and aromatic hydroxylation, N-dealkylation and glucuronidation; in addition, glucuronides of the hydroxy-metabolites are formed. The metabolism of Zenebi by aromatic hydroxylation is subject to the CYP2D6 dependent genetic oxidative polymorphism. The oral bioavailability of Zenebi averages 12% in fast metabolisers and is virtually complete in slow metabolisers. At steady state and at the same dose level, the peak plasma concentration of unchanged Zenebi is about 23 times higher in poor metabolisers than in extensive metabolisers. When unchanged active substance plus active metabolites are considered, the difference in peak plasma concentrations is 1.3 to 1.4 fold. Because of the variation in rates of metabolism, the dose of Zenebi tablets should always be adjusted to the individual requirements of the patient: poor metabolisers therefore may require lower doses.

In fast metabolisers, elimination half-lives of the Zenebi enantiomers average 10 hours. In slow metabolisers, they are 3-5 times longer. In fast metabolisers, plasma levels of the RSSS-enantiomer are slightly higher than for the SRRR-enantiomer. In slow metabolisers, this difference is larger. In fast metabolisers, elimination half-lives of the hydroxymetabolites of both enantiomers average 24 hours, and are about twice as long in slow metabolisers.

Steady-state plasma levels in most subjects (fast metabolisers) are reached within 24 hours for Zenebi and within a few days for the hydroxy-metabolites.

Plasma concentrations are dose-proportional between 1 and 30 mg. The pharmacokinetics of Zenebi are not affected by age.

In plasma, both Zenebi enantiomers are predominantly bound to albumin.

Plasma protein binding is 98.1% for SRRR-Zenebi and 97.9% for RSSS-Zenebi.

One week after administration, 38% of the dose is excreted in the urine and 48% in the faeces. Urinary excretion of unchanged Zenebi is less than 0.5% of the dose.

Non-clinical data reveal no special hazard for humans based on conventional studies of genotoxicity and carcinogenic potential.

Not applicable.

No special requirements.