In 2016, 325 000 people received a beta-blocker from a community pharmacy in New Zealand:1
- 72% were prescribed metoprolol succinate; the seventh most prescribed medicine in New Zealand
- 7% were prescribed bisoprolol
- 5% were prescribed atenolol
- 4% were prescribed carvedilol or propanolol
This pattern of prescribing is different to other countries, such as Australia where less than 5% of patients are
prescribed metoprolol succinate.2
Why is metoprolol succinate prescribed so widely?
It is likely that metoprolol succinate is the beta-blocker of choice among New Zealand prescribers because it has a
wide range of indications, i.e. angina, arrhythmia, heart failure, hypertension and post-myocardial infarction, it is
dosed once-daily and it is cardioselective (see below). The innovator brand (Betaloc) was also heavily marketed in New
Zealand before alternative options, e.g. bisoprolol, were subsidised.
Reliance on one medicine may cause problems
The recent disruption of the supply of metoprolol succinate where dispensing was limited to fortnightly or monthly amounts
highlights the risk of depending on one beta-blocker. A review of the different properties of beta-blockers, their role
in different cardiovascular conditions and co-morbidities is therefore timely.
All beta-blockers produce competitive antagonism of beta-adrenoceptors in the autonomic nervous system.3 This
prevents the “flight or fight” response induced by adrenaline and noradrenaline.3 It is the pharmacological
differences, such as beta-adrenergic selectivity, lipid solubility and dual receptor activity, which make each beta-blocker
unique. Research is ongoing into the complex ways in which these properties translate into treatment effects for patients.
Non-selective, cardioselective and vasodilating beta-blockers
Beta-blockers are classified according to their adrenoceptor binding affinities (Table 1), the degree
of which varies within each class.
There are three main sub-types of beta-adrenoceptors:3
- Beta1-adrenoceptors (75%) are located in the heart
- Beta2-adrenoceptors are located in vascular and bronchial smooth muscle
- Beta3-adrenoceptors are located on adipocytes and are thought to be involved with fatty acid metabolism
Some beta-blockers, e.g. carvedilol, also bind to alpha-adrenoceptors and prevent contraction of vascular smooth muscle.
Non-selective beta-blockers, e.g. propanolol, block beta1 and beta2-adrenoceptors equally.
Cardioselective beta-blockers, e.g. atenolol, bisoprolol and metoprolol, have a greater affinity for
beta1-adrenoceptors and are less likely to cause constriction of airways or peripheral vasculature and are
preferred in patients with respiratory disease. Bisoprolol is reported to be more cardioselective than metoprolol and atenolol.4
Vasodilating beta-blockers, e.g. carvedilol, reduce peripheral resistance by binding to alpha-adrenoceptors,
causing vasodilation without affecting cardiac output.3 It has been suggested that this may be preferable in
patients with insulin resistance, although strong evidence of a benefit is lacking.3 In addition to alpha1-blockade,
carvedilol binds non-selectively to beta1 and beta2-adrenoceptors.3
Celiprolol and pindolol have intrinsic sympathomimetic activity (ISA) and therefore simultaneously
block and stimulate beta-adrenoceptors causing less bradycardia and peripheral vasoconstriction.5 This may
be desirable in patients with peripheral artery disease but less beneficial in patients with heart failure or angina.
Table 1: Properties of beta-blockers subsidised in New Zealand.
||Renal / hepatic
*Intrinsic sympathomimetic activity
Beta-blockers can be water or lipid soluble
Water-soluble beta-blockers, e.g. atenolol, are excreted via the kidneys and dose reductions may be necessary in patients
with reduced renal function.3, 5 Lipid-soluble beta blockers, e.g. carvediolol or metoprolol, are metabolised
in the liver and may be better tolerated by patients with reduced renal function.3
Bisoprolol is processed by both the liver and kidneys therefore does not require dose adjustments for patients with
either renal or liver dysfunction,6 and is also less likely to interact with other medicines.
Beta-blockers may influence other medicines
All beta-blockers can potentiate bradycardia, hypotension and cardiac effects caused by other medicines, e.g. diltiazem.
Beta-blockers that are metabolised by hepatic enzymes may also interact with medicines that are metabolised via the same pathway.
The NZF interactions checker provides details on medicine interactions, including their clinical significance,
available from: www.nzf.org.nz
The indications for beta-blockers have shifted over the years. Originally widely prescribed for hypertension and contraindicated
for the treatment of heart failure, beta-blockers now have a limited role in the treatment of hypertension and are routinely
prescribed to patients with heart failure. The benefits of beta-blockers post-myocardial infarction are also no longer
as clear as they once were.
Stable angina: preference and co-morbidities determines treatment choice
Beta-blockers or calcium channel blockers are recommended as the first-line anti-anginal medicines.7 There
is no evidence that one beta-blocker is superior to another or that beta-blockers are superior to calcium channel blockers.8 The
choice of beta-blocker is largely determined by the presence of co-morbidities, prescriber experience and the patient’s
preference for frequency of dosing and their likely adherence to treatment. A cardioselective beta-blocker such as bisoprolol
or metoprolol succinate will provide the maximum effect with the minimum amount of adverse effects. Beta-blockers that
reduce resting heart rate less than others (due to ISA) tend not to be used for angina, e.g. celiprolol and pindolol.
Information on the management of stable angina is available from:
Arrhythmias: bisoprolol and metoprolol succinate are often preferred
Beta-blockers are the first-line treatment for long-term symptomatic rate control in patients with a range of cardiac
arrhythmias, including atrial fibrillation and ventricular tachycardia.9, 10 Bisoprolol* or metoprolol succinate
are first-choice beta-blockers for patients with atrial fibrillation as they are prescribed once-daily and do not require
dose adjustment in patients with renal impairment. Bisoprolol is preferred as it is more cardioselective than metoprolol
and may cause more bradycardia.
Sotalol should not be used for rate control in atrial fibrillation due to its pro-arrhythmic action. Sotalol is used
exclusively for rhythm control in patients with supraventricular and ventricular arrhythmias, but use
has declined since the SWORD (survival with oral d-sotalol) study in the 1990s was discontinued when
it was found that sotalol was associated with a higher rate of sudden death when administered to patients
after myocardial infarction.11 Alternatives
for rhythm control include flecainide in younger patients or amiodarone in older patients.
* Unapproved use
Information on the management of atrial fibrillation is available from: bpac.org.nz/2017/af.aspx
Heart failure: evidence for bisoprolol, carvediolol and metoprolol succinate
Beta-blockers are initiated alongside an ACE inhibitor in all patients with heart failure with reduced ejection fraction
(HF-REF) after a diuretic has reduced the patient’s fluid overload. Bisoprolol, carvedilol or metoprolol succinate
are generally prescribed for heart failure in New Zealand; there is no strong evidence of effectiveness for one
over another.12 In
practice, carvedilol is usually first-line if heart failure is associated with atrial fibrillation, followed
by bisoprolol or metoprolol succinate. Any of these three choices are appropriate if heart failure is associated
with ischaemic heart disease, but it is important that the beta-blocker is slowly titrated to maximum tolerated dose.
Patients with heart failure with preserved ejection fraction (HF-PEF) may also be prescribed a beta-blocker if they
have other cardiovascular co-morbidities, such as atrial fibrillation or hypertension.12
Information on the management of heart failure is available from:
Hypertension: beta-blockers are fourth-line
For patients with uncomplicated hypertension beta-blockers are generally a fourth-line option as angiotensin converting
enzyme (ACE) inhibitors, angiotensin II receptor blockers (ARBs), diuretics or calcium channel blockers are associated
with better outcomes.13 Beta-blockers may be more effective in younger patients with hypertension than older
patients and may be used to manage hypertension in females of reproductive age.
There is no evidence that one beta-blocker is superior to any other for the management of hypertension.13 If
a beta-blocker is prescribed the choice is based on the presence of co-morbidities, prescriber experience and the patient’s
preference for frequency of dosing and their likely adherence to treatment.
Information on the management of hypertension is available from: bpac.org.nz/BPJ/2013/August/hypertension.aspx
Post-myocardial infarction: initiated in secondary care, but when should they be stopped?
Beta-blockers are given acutely as first-line treatment post-myocardial infarction to decrease infarct size, increase
the threshold for ventricular arrhythmias, and in the long-term, to prevent dysfunctional ventricular remodelling and
heart failure.14 Bisoprolol or metoprolol succinate are usually prescribed as they are the most cardioselective
beta-blockers, but there is evidence of benefit for a number of other beta-blockers and international guidelines do not
specify which beta-blocker to prescribe.15, 16
Withdrawal of beta-blockers may be appropriate at 6–12-months post-myocardial infarction if re-vascularisation has occurred
At 6–12-months post-myocardial infarction prescribers are encouraged to consider withdrawing beta-blockers from patients
without atrial fibrillation or heart failure, if re-vascularisation occurred while they were being treated
for their myocardial infarction. If re-vascularisation did not occur the beta-blocker is likely to be
required long term to prevent angina or if there is poor ventricular function. This is an evolving area of research
and increasingly the evidence appears to support the withdrawal of beta-blockers from patients without other indications
for treatment, e.g. heart failure or arrhythmias (see: “The optimal duration of treatment
post-myocardial infarction is uncertain”).
Information on the management of acute coronary syndromes is available from:
The optimal duration of treatment post-myocardial infarction is uncertain
There are two reasons why the optimal duration of beta-blocker treatment post-myocardial infarction is uncertain:16
- Reperfusion techniques and the routine use of statins and anti-platelet medicines post-myocardial infarction mean
that patients now gain less benefit from the use of beta-blockers than they did decades ago
- There are no recent prospective randomised studies assessing the long-term benefits of beta-blockers in patients
with uncomplicated myocardial infarction
A systematic review of sixty trials that divided studies into either the reperfusion era or the pre-reperfusion era,
found that beta-blockers reduced mortality in patients post-myocardial infarction in the pre-reperfusion era, but not
the reperfusion era.17 Beta-blockers in the reperfusion era do, however, reduce the risk of subsequent angina
(number needed to treat [NNT] 26) and the risk of recurrent myocardial infarction (NNT 209).17
Guidelines support the use of a beta-blocker for one to three years post-myocardial infarction,18, 19 but
in practice they are now being stopped earlier in patients who are otherwise well, with no signs of angina or heart failure.
The adverse effect profile varies between beta-blockers according to their properties (Table 1). Tolerance to treatment
may be improved with a slow upward titration of the beta-blocker until the maintenance dose is established. Approximately
3 – 5% of patients can be expected to be intolerant to beta-blocker treatment due to hypotension or bradycardia.20
Table 2 summarises recommended choices of beta-blocker, depending on the indication,
patient co-morbidities and adverse effects.
Initiating beta-blockers: start low and go slow if treating heart failure
Beta-blockers should be started at a low dose and slowly titrated to maximum tolerated dose when used to treat patients
with heart failure. For atrial fibrillation, the starting dose of the beta-blocker depends on the patient’s heart rate
and co-morbidities, e.g. a starting dose of 23.75 mg metoprolol succinate may be appropriate for a patient with moderately
elevated heart rate, but 47.5 mg may be required for a patient with a significantly elevated heart rate. For other conditions,
e.g. angina, a beta-blocker can usually be started at a standard dose.
Refer to the New Zealand Formulary for individual beta-blocker dosing regimens: www.nzf.org.nz
Titrating dose in heart failure
Begin treatment with a beta-blocker at a low dose and gradually increase this to the recommended dose or the maximum
tolerated dose. Record the patient’s heart rate and blood pressure before treatment is initiated and continue to monitor
these as the dose is titrated upwards.12 Adverse effects will often resolve and patients can be encouraged
to persist with treatment as long as their systolic blood pressure does not fall too low, e.g. less than 100 mmHg. If
adverse effects do not resolve, drop back to the previous dose and assess symptom control.
Beta-blockers are usually not recommended in patients with asthma
Beta-blockers should generally be avoided in patients with asthma.21 This is because they may prevent sympathetic
stimulation of the pulmonary beta2-adrenoceptors thus causing bronchoconstriction and reducing the effectiveness
If a beta-blocker must be used in a patient with asthma, cardioselective beta-blockers, e.g. bisoprolol and metoprolol,
are better tolerated than non-selective beta-blockers, although they are still associated with a decrease in lung function
and adverse effects.22
Cardioselective beta-blockers are generally safe and beneficial in patients with COPD
There is evidence that beta-blockers are under-prescribed to patients with COPD, yet they provide significant benefit
to those with co-existing heart failure;23 cardioselective beta-blockers are preferred. A systematic review
which included 15 studies with a follow-up period ranging from one to seven years found that beta-blockers in patients
with COPD significantly decreased overall mortality and exacerbation of COPD.24
Cardioselective beta-blockers may reduce peripheral vasoconstriction and fatigue
Cardioselective beta-blockers, e.g. bisoprolol and metoprolol succinate, are less likely to cause fatigue and cold extremities
than non-selective beta-blockers.21 However, peripheral vasoconstriction may still occur due to the reduction
in cardiac output.21 If patients report cold extremities when taking a beta-blocker, a dihydropyridine calcium
channel blocker can be added to their treatment regimen, e.g. amlodipine. If the patient’s blood pressure is “on target”,
the beta-blocker can be reduced, otherwise it should be left at the same dose.
Water soluble beta-blockers are less likely to cause sleep disturbances
Malaise, vivid dreams, nightmares and in rare cases hallucinations may be caused by lipid-soluble beta-blockers crossing
the blood brain barrier.21 If a patient reports adverse effects related to the central nervous system that
cannot be managed with a dose reduction, consideration may be given to switching treatment to a water-soluble beta-blocker,
e.g. atenolol, celiprolol or nadolol.
Table 2: Summary of indications, recommendations and considerations for the use of beta-blockers for cardiovascular conditions in New Zealand.
||Co-morbidities and considerations
All beta-blockers are considered to be equally effective although bisprolol or metoprolol may be preferred. Celiprolol
and pindolol tend not to be used
Cardioselective beta-blockers, e.g. bisoprolol or metoprolol, are less likely to cause adverse effects, e.g. cold extremities or fatigue
Celiprolol and pindolol have ISA which may reduce bradycardia or peripheral vasoconstriction
Water soluble beta-blockers, e.g. atenolol, celiprolol or nadolol, are less likely to cause CNS adverse effects,
such as sleep disturbances
Polypharmacy: bisoprolol is less likely to interact with other medicines
Renal dysfunction: consider dose adjustments for water-soluble beta-blockers, e.g. atenolol, celiprolol and nadolol;
bisoprolol may be preferred
Respiratory disease: cardioselective beta-blockers, e.g. bisoprolol and metoprolol, are preferred
Metoprolol or bisoprolol
Bisoprolol, carvedilol or metoprolol
All beta-blockers are considered to be equally effective (as fourth-line treatment)
Bisoprolol or metoprolol; consider withdrawal after 6–12 months if re-vascularised and no other indications.
Treatment with beta-blockers is generally long-term, but it should not be regarded as indefinite. Occasionally it may
be necessary to temporarily withdraw treatment, e.g. if the patient develops lower limb ulcers. In the long-term, the
emergence of co-morbidities may make management more complex and it is appropriate to periodically review the benefits
and risks of treatment with beta-blockers.
Stopping treatment: go slow to get low
Beta-blockers should be withdrawn slowly to prevent the onset of a withdrawal syndrome which in serious cases may include
ischaemic cardiac symptoms, e.g. chest pain, even in those with no history of coronary heart disease. The risk of myocardial
infarction is increased for older patients during the first month of withdrawal from cardioselective beta-blockers and
this increased risk continues for six months.25 Heart rate and blood pressure should be monitored as the
dose is reduced and the patient’s cardiac receptors and sympathetic nerve activity down-regulate.3, 26
There are no specific guidelines for withdrawing beta-blockers. A practical approach would be to reduce the patient’s
dose over several months, e.g. down titrating a twice daily dose to once daily for one month and then further reducing
the dose to every second day for another month, before stopping treatment completely at the time when the patient’s next
prescription would be due. The dose could be halved every week for patients who needed to withdraw from treatment more
Further information on beta-blockers is available in the podcast: the “Rational use of beta-blockers” with Dr Linda