Atenolol and Beta-Blockers: Independent Evidence on Hypertension

Table of contents

• Evidence summary
• What atenolol is
• How it works
• What it is prescribed for
• What works and what does not
• Benefits by claim
• Atenolol versus bisoprolol
• Risks and all side effects
• All interactions
• Who should avoid atenolol
• Dosage and how to take it
• Follow the money: who makes it and who funded the evidence
• Related research
• Frequently asked questions
• Sources and funding notes

Evidence summary

Independent evidence and credibility scorecard

Independence tiers: 1 = government, regulator or public registry with no stake in the result; 2 = academic or Cochrane team, or a regulator-approved label written by the licence holder, with no declared commercial funding for the work; 3 = trade press or interested secondary reporting; 4 = produced, funded or sponsored by a drug maker or its employees. Credibility runs from A (highest) to D.

Country clustering: the sources are mainly from the UK, US and Sweden, with the Cochrane hypertension review from South Africa. The two sponsored trials were run by Scandinavian and UK investigators with US and UK drug-company funding. This means the verdict reflects Western regulatory and research lenses, and that the UK guideline (NICE) is the main guidance source we could open.

What atenolol is

Atenolol is a beta-1-selective beta-adrenoceptor blocker, ATC code C07AB03 (UK Tenormin SmPC). It has no intrinsic sympathomimetic activity and no membrane-stabilising activity. In the UK the generic and the brand are prescription-only medicines.

• Brand names: Tenormin (tablets, and a combination with chlorthalidone called Tenoretic). The US drug database lists three active Tenormin products under NDA 018240, while an AstraZeneca-held Tenormin application (NDA 019058) is marked "Discontinued" (Drugs@FDA via openFDA).
• Generics: openFDA lists 10 abbreviated (generic) applications containing atenolol in the generic name, which may include combination products (openFDA query). In the UK, generic atenolol 50 mg tablets are licensed to Milpharm, part of the Aurobindo group (UK SmPC).
• Forms: 25 mg, 50 mg and 100 mg tablets are the usual forms. A Tenormin injection is also listed in the UK.
• Older beta-blockers: this article covers atenolol and the older class generally. The Cochrane review notes that atenolol was the most-used beta-blocker in the trials, and that no outcome trials were found for newer vasodilating beta-blockers such as nebivolol (Cochrane 2017).

How it works

Atenolol blocks beta-1 receptors, mainly in the heart, which slows the heart rate and reduces the force of each beat. The UK label is candid about hypertension: "the mode of action of atenolol in the treatment of hypertension is unclear". It is probably the effect on heart rate and contractility that relieves angina (UK SmPC 5.1). Selectivity decreases as the dose goes up.

Pharmacokinetics that matter in practice

• Absorption: about 40 to 50% of an oral dose is absorbed, with peak levels 2 to 4 hours after a dose (UK SmPC 5.2; FDA label).
• Elimination: little or no liver metabolism; the kidney is the main route, so kidney disease raises blood levels. The half-life is about 6 hours in the UK label and 6 to 7 hours in the US label.
• Brain penetration: low, because atenolol is poorly fat-soluble (UK SmPC 5.2).
• Proven in people versus theory: blood pressure lowering and the heart-rate effects are proven in humans. Why atenolol may protect less against stroke than other drugs is not settled in the sources we opened. We did not find a source that proves a mechanism, so we do not offer one.

What it is prescribed for

Licensed uses

Where guidelines place it

• NICE NG136 (UK): step 1 is an ACE inhibitor or ARB for people with type 2 diabetes, or under 55 who are not of Black African or African-Caribbean family origin (1.4.32), and a calcium-channel blocker for people aged 55 or over, or of Black African or African-Caribbean family origin, without type 2 diabetes (1.4.35). Beta-blockers are not step 1 options. At step 4 for resistant hypertension, NICE says to consider an alpha-blocker or beta-blocker when potassium is above 4.5 mmol/l (1.4.51) (NICE NG136).
• Why NICE dropped beta-blockers: the 2019 committee removed the older advice to consider beta-blockers in some younger people because they are rarely used at step 1 now and no established relationship between their use in primary hypertension and fewer cardiovascular events was found. It said this fitted most international guidelines (NICE rationale). We did not open those international guidelines ourselves.
• Other conditions: a beta-blocker may be chosen for angina, a previous heart attack, heart failure with reduced ejection fraction or some rhythm problems. Those decisions follow separate guidance. See our pages on stable angina, heart failure with reduced ejection fraction and atrial fibrillation.

This is a description of where atenolol sits, not advice to start or stop it.

What works and what does not

Benefits by claim

"Beta-blockers are a good first drug for high blood pressure"

The Cochrane review of beta-blockers as first-line treatment included 13 randomised trials. About 40,245 participants took beta-blockers, around three-quarters of them atenolol. The authors rated most trials at high risk of bias. Their conclusion: initiating treatment with beta-blockers gives modest reductions in cardiovascular disease and little or no effect on mortality, and effects are inferior to other antihypertensives (Wiysonge et al., Cochrane 2017).

Reading the numbers: an RR of 1.24 means 24% more strokes relative to the comparison group's rate, not 24 more strokes per 100 people. The absolute difference depends on baseline risk. One trial of people aged 65 or over found atenolol had more coronary events than a diuretic (RR 1.63, 95% CI 1.15 to 2.32), but that is a single trial.

"Atenolol itself is the problem"

A Lancet meta-analysis restricted to atenolol found no difference from placebo for deaths, cardiovascular deaths or heart attack across four trials (6,825 patients), and a higher death rate than other active drugs across five trials (17,671 patients; RR 1.13, 95% CI 1.02 to 1.25). Stroke tended to be lower than placebo (RR 0.85) but not clearly so. The authors wrote that the results cast doubt on atenolol as a suitable drug for hypertension (Carlberg et al., Lancet 2004). This analysis predates the 2017 Cochrane review, and the latter reached a similar broad conclusion with more trials.

Head-to-head: LIFE and ASCOT-BPLA (both sponsored)

LIFE (industry-sponsored). In 9,193 adults aged 55 to 80 with hypertension and thickened heart muscle on ECG, blood pressure fell by about the same amount on losartan and atenolol (30.2/16.6 vs 29.1/16.8 mmHg). The main composite of cardiovascular death, heart attack and stroke was lower on losartan (508 vs 588 events; RR 0.87, 95% CI 0.77 to 0.98). The difference came from stroke (232 vs 309; RR 0.75, 0.63 to 0.89). Heart attacks were not lower (198 vs 188; RR 1.07, 0.88 to 1.31), and cardiovascular deaths were similar (RR 0.89, 0.73 to 1.07). New-onset diabetes was less frequent on losartan (Dahlöf et al., Lancet 2002). ClinicalTrials.gov lists the sponsor as Organon and Co, classed as industry (registry record).

ASCOT-BPLA (Pfizer-supported). 19,257 hypertensive patients aged 40 to 79 with at least three other cardiovascular risk factors received amlodipine (adding perindopril as required) or atenolol (adding bendroflumethiazide as required). The trial was stopped early after a median 5.5 years. The main endpoint, non-fatal heart attack plus fatal heart disease, was not significantly different (429 vs 474 events; HR 0.90, 95% CI 0.79 to 1.02). But stroke (327 vs 422; HR 0.77, 0.66 to 0.89), all-cause deaths (738 vs 820; HR 0.89, 0.81 to 0.99), total cardiovascular events and procedures (1,362 vs 1,602; HR 0.84, 0.78 to 0.90) and new diabetes (567 vs 799; HR 0.70, 0.63 to 0.78) all favoured amlodipine. The authors said the effects may not be fully explained by blood-pressure control (Dahlöf et al., Lancet 2005). A community summary reports blood pressure averaged 2.7/1.9 mmHg lower in the amlodipine arm and that several authors had personal funding from blood-pressure or lipid drug makers (WikiJournalClub).

Why we still use these trials. The sponsor is the maker of the winning regimen in both. That is a reason to read the results with care, not a reason to reject them. The same direction of effect, in the same drug (atenolol), appears in the independent Cochrane and Lancet reviews, which pooled many trials. Where opposing-interest sources converge, our confidence rises. Note that in both trials atenolol was the comparator, and the winning regimens were also multi-drug regimens, so these trials compare strategies, not single pills.

Diabetes risk

A network meta-analysis of 22 trials (143,153 people without diabetes) found incident diabetes in 7.57% of people starting on beta-blockers, 6.81% on placebo, and 5.34% on diuretics. Odds ratios against initial diuretics were 0.57 for ARBs, 0.67 for ACE inhibitors, 0.75 for calcium-channel blockers, 0.77 for placebo and 0.90 (0.75 to 1.09) for beta-blockers. The authors ranked beta-blockers and diuretics as the classes most associated with new diabetes (Elliott and Meyer, Lancet 2007). ASCOT-BPLA's diabetes hazard ratio of 0.70 for the amlodipine regimen fits the same direction. The US label also warns that beta-blockers can hide the early signs of low blood sugar (FDA label).

Withdrawal and rebound

Beta-blockers hold the heart rate and blood pressure down. After sudden withdrawal, some people have a rebound. The US label reports severe worsening of angina, heart attack and ventricular arrhythmias in angina patients after abrupt stopping, and says it may be prudent not to stop abruptly even when used only for hypertension (FDA label). The UK label asks for gradual withdrawal over 7 to 14 days with follow-up (UK SmPC 4.4). The US label also warns that stopping may precipitate a thyroid storm in people with undiagnosed thyroid overactivity. We did not find an independent trial that measured the rate of rebound events after stopping atenolol; the warning rests on label text and clinical reports.

Atenolol versus bisoprolol

We found no head-to-head outcome trial of atenolol versus bisoprolol in hypertension. The Cochrane review reports that beta-blockers are "a diverse group" and that almost all the outcome data come from atenolol (Cochrane 2017 full text), so its findings should not be assumed to apply to bisoprolol. Differences that the labels do show:

For full details on bisoprolol, see our page on bisoprolol. Choice between the two is a prescriber's decision based on the condition being treated, kidney function and other medicines.

Risks and all side effects

The US label states that most adverse effects have been mild and transient. Its table below combines trials in which events were volunteered and ones in which they were elicited by checklist, so the rates are higher than in volunteered-only data (FDA label, Adverse Reactions).

Common side effects (hypertension trials)

The UK SmPC lists as common: slow pulse, cold extremities, gastrointestinal disturbance and fatigue. Uncommon: sleep disturbance and raised liver enzymes. Rare: low platelets and purpura, mood changes, nightmares, confusion, psychosis and hallucinations, dizziness, headache, tingling, dry eyes, visual disturbance, worsening heart failure, heart block, low blood pressure on standing with fainting, worse leg cramp on walking, Raynaud's phenomenon, wheeze in people with asthma, dry mouth, liver toxicity with cholestasis, hair loss, psoriasis-like skin reactions or worse psoriasis, rash, and impotence. Not known: depression, hypersensitivity reactions including angioedema and urticaria, and a lupus-like syndrome. Raised antinuclear antibodies are very rare (UK SmPC 4.8).

Masked hypoglycaemia and thyroid signs

The US label says beta-blockers may prevent early warning signs of low blood sugar, such as a fast pulse, and raise the chance of severe or prolonged hypoglycaemia, especially in people with diabetes, children and people who are fasting or vomiting. They can also mask signs of an overactive thyroid (FDA label).

Asthma and lung disease

The US label says people with bronchospastic disease should in general not receive beta-blockers, although atenolol's relative selectivity means it may be used with caution when other treatment fails. The UK label advises avoiding it in reversible airways obstruction unless there are compelling reasons (FDA label; UK SmPC 4.4).

Overdose

The US label reports survivors of acute doses as high as 5 g and one death in a man who may have taken as much as 10 g. Symptoms include lethargy, breathing disturbance, wheeze, sinus pause and a slow pulse, and any suspected overdose needs urgent medical help (FDA label, Overdosage).

All interactions

Atenolol is not much metabolised by the liver, so it has few enzyme-based interactions. Most come from additive effects on the heart and blood pressure.

Our other blood-pressure pages may also help, including blood pressure medicines and amlodipine.

Who should avoid atenolol

Contraindications

• UK: hypersensitivity; cardiogenic shock; uncontrolled heart failure; sick sinus syndrome; second- or third-degree heart block; untreated phaeochromocytoma; metabolic acidosis; resting bradycardia below 45 beats a minute; hypotension; and severe peripheral arterial circulatory disturbances (UK SmPC 4.3).
• US: sinus bradycardia, heart block greater than first degree, cardiogenic shock, overt cardiac failure and hypersensitivity (FDA label).

Use with care

The UK label asks for caution in first-degree heart block, in poor cardiac reserve, in Prinzmetal's angina, in milder peripheral arterial disease, in diabetes, in older people and in kidney impairment (UK SmPC 4.4).

Children

The UK label says there is no paediatric experience and it is not recommended. The US label says safety and effectiveness in children have not been established (UK SmPC 4.2; FDA label).

Older adults

The US label says trials did not include enough people aged 65 and over to say whether they respond differently, and advises starting at the low end of the dose range (FDA label, Geriatric Use). The Cochrane review found one trial in people aged 65 or over in which atenolol had more coronary events than a diuretic (RR 1.63, 95% CI 1.15 to 2.32) (Cochrane 2017).

Pregnancy

• US label: atenolol "can cause fetal harm". Second-trimester starts have been associated with small-for-gestational-age infants. No first-trimester studies exist, so fetal injury cannot be excluded (FDA label, Warnings).
• UK label: administration in mild to moderate hypertension has been associated with intra-uterine growth retardation. The benefit must be weighed against the risk, particularly in the first and second trimesters (UK SmPC 4.6).
• Cohort evidence: in 312 pregnancies in a Birmingham antenatal hypertension clinic, atenolol monotherapy (78 pregnancies) was linked with lower birth weight and ponderal index, and a trend towards more preterm and small-for-gestational-age babies. The effect was greater with earlier starts and longer use (Lydakis et al., 1999). It was a retrospective study, so sicker mothers may have been treated more.
• Pooled trials: the Cochrane review of 63 trials (5,909 women with data) found antihypertensive drugs overall probably halve severe hypertension (RR 0.49, 0.40 to 0.60) with little or no change in small-for-gestational-age babies (RR 0.96, 0.78 to 1.18). That result pools all drug classes and is not specific to atenolol (Abalos et al., Cochrane 2018).
• NICE: for chronic hypertension in pregnancy consider labetalol, then nifedipine if labetalol is unsuitable, then methyldopa (NICE NG133 1.3.10). NICE NG136 says women of childbearing potential should be offered treatment in line with the guideline, and those considering pregnancy should follow the pregnancy guideline (NICE NG136 1.4.29).

Pregnant or planning pregnancy? Do not change medicine without clinical advice. See also our page on heart disease during pregnancy.

Breastfeeding

The US label says atenolol is excreted into breast milk at a milk-to-plasma ratio of 1.5 to 6.8, and clinically significant slow pulse has been reported in breastfed infants. Neonates may be at risk of low blood sugar and slow pulse (FDA label). The UK label also notes significant accumulation in breast milk (UK SmPC 4.6).

Kidney disease

Because the kidney clears atenolol, doses are reduced in kidney impairment (see dosage below) and haemodialysis patients are dosed under hospital supervision (UK SmPC 4.2).

Dosage and how to take it

Your prescriber sets the dose. The figures below are label doses for context only. They are not a guide to self-dosing.

How to take it

MedlinePlus says to take it by mouth once or twice daily at the same times each day, that full benefit may take one to two weeks, and not to stop without talking to a doctor even if you feel well (MedlinePlus). Get up slowly from sitting or lying to reduce dizziness; see also our page on orthostatic hypotension. Home readings can show whether treatment is working: home blood pressure monitoring.

How long to take it, and stopping

High blood pressure treatment is usually long term. The UK label says atenolol should not be withdrawn abruptly and that the dose should be withdrawn gradually over 7 to 14 days with follow-up, especially in ischaemic heart disease (UK SmPC 4.4). This is label wording describing how the product is meant to be stopped; any plan is for your prescriber.

Before surgery

The UK label says that if beta-blockade is to be stopped before surgery it should be done at least 24 hours beforehand, while the US label says chronic therapy should not be routinely withdrawn before major surgery. Tell the anaesthetist either way (UK SmPC 4.4; FDA label).

Quality issues

The openFDA enforcement database lists 5 recall records with atenolol in the product description. They include a 2022 Class I recall in which a bottle labelled atenolol 25 mg contained clopidogrel, and Class II recalls in 2014 and 2017 for oversized tablets and foreign tablets (openFDA enforcement query). These are packaging and quality events, not safety signals about the drug itself.

Follow the money: who makes it and who funded the evidence

Who made it, and who sells it now

• Origin: an AstraZeneca process chemist's timeline records that ICI Pharmaceuticals Division was created in 1957 and began a beta-blocker research programme in 1958. It launched propranolol (Inderal) in 1965. Atenolol entered development in 1972 and was launched as Tenormin in 1976. Peak sales and patent expiry in major markets fell between 1987 and 1990. Zeneca demerged from ICI in 1993, and Astra and Zeneca merged in 1999. In 2007 Tenormin was still on AstraZeneca's range (Jolly, SCI 2007). This is the company's own account, which we use only for dates.
• 2020 sale: in January 2020 AstraZeneca agreed to sell the commercial rights to Inderal, Tenormin, Tenoretic, Zestril and Zestoretic to the UK-based Atnahs Pharma. The deal excluded the US and India (divested earlier) and Japan (kept by AstraZeneca). Atnahs paid $350 million upfront, with up to $40 million of sales-linked payments between 2020 and 2022. The five brands had about $132 million of annual sales in 2018 across the markets covered, and Tenormin's share was not separated (BioSpectrum, 29 January 2020). The UK Tenormin licence is held by Atnahs Pharma UK Limited (UK SmPC).
• United States: openFDA lists Tenormin under NDA 018240 with sponsor "TWI Pharms", and the label we used is from Upsher-Smith Laboratories, effective 18 September 2025 (Drugs@FDA via openFDA; FDA label). We could not trace how the US brand rights moved between these companies.
• Generic market: a generic maker's 2007 press release said atenolol generics and Tenormin together had annual US sales of about $102 million for the twelve months to March 2007, citing IMS data (Caraco, 11 July 2007). That is a 19-year-old figure from a seller with an interest in the market. We found no current citable atenolol sales figure.

Who funded the key evidence

• Cochrane 2017: internal support from the South African Medical Research Council, Stellenbosch University, University of the Western Cape and University of Cape Town. External sources: none supplied. The authors declared no affiliation with any entity with a direct financial interest in the subject (full text). We could not see per-trial funding in the version we opened.
• LIFE: ClinicalTrials.gov lists the lead sponsor as Organon and Co, class industry; the study ran from 1995 to 2001 (registry record). Organon's registered business address is Jersey City, New Jersey (SEC EDGAR). We could not open the Lancet paper's own funding statement, which returned an access block.
• ASCOT-BPLA: financial support mainly from Pfizer, which makes amlodipine (Norvasc), per a community summary of the paper (WikiJournalClub). Pfizer's registered business address is New York (SEC EDGAR). The Lancet paper itself was not accessible to us, so please check its funding and conflict statements directly. An ASCOT post-trial follow-up study is listed with Imperial College London as lead sponsor (ClinicalTrials.gov NCT01499511).
• Elliott and Meyer 2007: a US public career grant (NHLBI K25 HL68139) (PubMed record).
• Abalos 2018 (pregnancy): UK Medical Research Council grant G116/98 listed in the record (PubMed record).

Documented integrity events

We searched the US regulator's recall database and found 5 records for atenolol products, all about packaging or tablet quality (openFDA enforcement). We found no regulatory ban, FTC action or lawsuit specific to atenolol in the sources we opened. The main controversy is scientific: whether atenolol, the most-used comparator in the 1990s and 2000s hypertension trials, was a fair benchmark. Carlberg and colleagues argued it should not be used as a reference drug (Carlberg 2004). Our inference, not a finding in the sources, is that some "new drug beats old drug" results may partly reflect the choice of old drug, a point to weigh alongside the sponsor's interest in the new drug.

What this means: the strongest findings that atenolol does worse than other drug classes come from independent reviews, and the two sponsored head-to-head trials point the same way. The drug is now a cheap generic. Our inference is that no company has a strong incentive to fund a new large trial of atenolol today.

Related research

For wider, evidence-graded context, see these Pure City Research guides:

• Hypertension: accurate measurement, treatment, safety and evidence funding
• Blood pressure medicines: types, monitoring, side effects and safety
• Resistant hypertension (where a beta-blocker may be a step-4 option)
• Home blood pressure monitoring
• High blood pressure: prevention and management evidence
• Diabetes and heart disease

Sibling medicine reviews:

• Bisoprolol
• Propranolol for anxiety
• Amlodipine
• Losartan
• Ramipril
• Stable angina
• Heart failure with reduced ejection fraction
• Heart disease during pregnancy

Frequently asked questions

Sources and funding notes

What we could not verify:

• We could not open the full text of the LIFE and ASCOT-BPLA papers (the publisher blocked access), so the sponsor and conflict-of-interest statements come from ClinicalTrials.gov (LIFE) and a community summary (ASCOT). Please check the papers directly.
• We did not open the 2024 European (ESC) or 2025 American hypertension guidelines. NICE's statement that its position is consistent with most international guidelines is the committee's claim, not ours.
• The Cochrane review's trial searches ran to June 2016 and most included trials are older. We did not find a newer independent pooled analysis in the searches we ran.
• The Cochrane full text we opened did not show funding for each included trial, and the Carlberg record showed no funding statement.
• We found no head-to-head outcome trial of atenolol and bisoprolol in hypertension, and no independent measurement of the rebound rate after stopping atenolol.
• We could not trace how the US Tenormin rights moved between AstraZeneca, TWI Pharmaceuticals and Upsher-Smith, who stands behind Atnahs Pharma, or atenolol-specific sales.
• We did not independently review the angina and post-heart-attack trials that support those licensed uses.

1. NICE NG136: Hypertension in adults: diagnosis and management and rationale and impact — UK government-funded guideline, last updated 26 February 2026.
2. NICE NG133: Hypertension in pregnancy: diagnosis and management — UK government-funded guideline, published 25 June 2019.
3. Wiysonge CS et al. Beta-blockers for hypertension. Cochrane 2017 (full text) — South Africa; internal university and research-council support; no external funding; no financial-interest declarations.
4. Carlberg B et al. Atenolol in hypertension: is it a wise choice? Lancet 2004 — Umeå University, Sweden; no funding statement in the record.
5. Elliott WJ, Meyer PM. Incident diabetes in clinical trials of antihypertensive drugs: a network meta-analysis. Lancet 2007 — Rush University, US; NHLBI grant K25 HL68139.
6. Abalos E et al. Antihypertensive drug therapy for mild to moderate hypertension during pregnancy. Cochrane 2018 — Argentina/UK; MRC grant G116/98 per Europe PMC record.
7. Lydakis C et al. Atenolol and fetal growth in pregnancies complicated by hypertension. Am J Hypertens 1999 — City Hospital Birmingham, UK; no grant listed.
8. Dahlöf B et al. LIFE: a randomised trial against atenolol. Lancet 2002 — industry-sponsored per ClinicalTrials.gov (Organon and Co).
9. Dahlöf B et al. ASCOT-BPLA. Lancet 2005 — Pfizer-supported per the secondary summary; with WikiJournalClub ASCOT-BPLA (community wiki).
10. ClinicalTrials.gov NCT00338260: LIFE study record — US National Library of Medicine registry.
11. FDA-approved Tenormin prescribing information via openFDA (Upsher-Smith, effective 18 September 2025) — US regulator-approved label.
12. Drugs@FDA via openFDA: Tenormin applications and generic applications query — US government data.
13. openFDA drug enforcement (recall) database, atenolol query — US government data.
14. Tenormin 100 mg tablets, UK SmPC (Atnahs Pharma UK, revised 6 March 2026); Atenolol 50 mg tablets, UK SmPC (Milpharm, revised 5 March 2026); Bisoprolol fumarate 5 mg tablets, UK SmPC (Viatris) — MHRA-approved, written by licence holders.
15. MedlinePlus: Atenolol (last revised 15 March 2026) — US National Library of Medicine; ASHP-sourced content.
16. Jolly S. Atenolol: 30 years of life cycle management, SCI symposium 2007 — AstraZeneca employee; company history, used for dates only.
17. BioSpectrum: AstraZeneca sells hypertension drugs for $350m to Atnahs (29 January 2020) — trade press.
18. Caraco Pharmaceutical Laboratories press release, 11 July 2007 — generic maker's marketing release.
19. SEC EDGAR: Pfizer company record and Organon & Co. company record — US government filing data (business addresses).

Educational research reviewed 6 October 2026. This article is not medical advice; talk to a qualified clinician or pharmacist before starting, stopping or combining treatments.