Atenolol

Medication beta blocker heart & blood pressure

Aka: Tenormin

Brands seen in Singapore: Prenolol, Tenol, Tenolol, Normaten, Urosin

Not medical advice. Check with your doctor or pharmacist before you start, stop or change the timing of anything you take.

How to use

What it’s for

SG label: hypertension and angina pectoris

When to take

Long-term use · HealthHub: not stopped suddenly after weeks

Take with

HealthHub: with or without food

Pros & cons

Pros

SG label: 50–100 mg a day covers both bp and angina
SG label: full effect usually seen within 1–2 weeks
50 mg and 100 mg tablets registered in SG

Cons

Dizziness, cold hands and feet and tiredness are common
SG label: contraindicated in asthma or airway disease
HealthHub: it can mask low-blood-sugar warning signs

Sources

HSA — Listing of Registered Therapeutic Products (data.gov.sg dataset d_767279312753558cbf19d48344577084), Forensicclassification column; all 5,511 rows cached at /tmp/hsa_all.json and filtered locally (not re-fetched), 27 Aug 2026 · read 2026-08-27
what it says
“PRENOLOL 50/100 SIN10277P/SIN10278P; TENOL 50 SIN07538P; TENOLOL 100 SIN02344P; NORMATEN 50/100 SIN07584P/SIN10391P; UROSIN 50/100 SIN12330P/SIN10116P; ATENOLOL 50/100 SIN08753P/SIN08755P; APO-ATENOL 50/100 — ATC C07AB03, all 14 atenolol rows Prescription Only”
MOH National Drug Formulary (Singapore) — UROSIN FILM COATED TABLET 50 MG [SIN12330P], product information · read 2026-08-27
what it says
“ATENOLOL - 50 MG … Registration Number SIN12330P … Forensic Classification PRESCRIPTION ONLY MEDICINES … ATC code C07AB03 … Prescription-only Medicines with Exemptions for Supply without Prescription NA … To be dispensed on physician's prescription”
MOH National Drug Formulary (Singapore) — ATENOLOL TABLET 50 MG [SIN08753P] (Beacons Pharmaceuticals), product information · read 2026-08-27
what it says
“ATENOLOL - 50 MG … Registration Number SIN08753P … Licence Holder BEACONS PHARMACEUTICALS PTE. LTD. … Forensic Classification PRESCRIPTION ONLY MEDICINES … ATC code C07AB03”
MOH National Drug Formulary (Singapore) — UROSIN [SIN12330P], Indication(s) · read 2026-08-27
what it says
“Indication(s): Hypertension, angina pectoris”
MOH National Drug Formulary (Singapore) — UROSIN [SIN12330P], Dosage and Administration: hypertension · read 2026-08-27
what it says
“Hypertension: 50–100mg per day alone or in conjunction with other antihypertensive agents. The full effects of this dosage will usually be seen within 1–2 weeks. Increasing the dosage more than 100mg is unlikely to produce more beneficial effects”
MOH National Drug Formulary (Singapore) — UROSIN [SIN12330P], Dosage and Administration: angina pectoris · read 2026-08-27
what it says
“Angina pectoris: The dosage for most patients is 50–100mg once a day or in divided doses. Increasing the dosage more than 100mg is unlikely to produce more beneficial effects”
MOH National Drug Formulary (Singapore) — UROSIN [SIN12330P], Contraindication(s) · read 2026-08-27
what it says
“Contraindicated in patients with sinus bradycardia, heart block greater than first degree, cardiogenic shock, and overt cardiac failure. It should not be used in patients with asthma or a history of obstructive airway diseases”
HealthHub (MOH Singapore) — Atenolol, medication information leaflet · read 2026-08-27
what it says
“Atenolol belongs to a group of medications known as beta-blockers … You may take this medication with or without food … do not stop this medication suddenly without consulting your healthcare professional. Stopping your medication suddenly may worsen your condition”
HealthHub (MOH Singapore) — Atenolol, precautions · read 2026-08-27
what it says
“You have asthma or other breathing problems – this medication may worsen or cause an asthma attack. You have pre-diabetes or diabetes - this medication may hide symptoms of low blood sugar such as fast heartbeat or tremors”
HealthHub (MOH Singapore) — Atenolol, common side effects · read 2026-08-27
what it says
“Dizziness and lightheadedness … Coldness, numbness or tingling sensation of your fingers or toes … Feeling weak and tired, and that your heart beats slower … Shortness of breath”
TENORMIN (atenolol) tablets — US prescribing information, openFDA drug label record (Upsher-Smith Laboratories, LLC) · read 2026-08-27
what it says
“brand_name: TENORMIN … generic_name: ATENOLOL … The initial dose of TENORMIN is 50 mg given as one tablet a day either alone or added to diuretic therapy”
TENORMIN (atenolol) tablets — US prescribing information, Dosage and Administration: hypertension and angina ceilings · read 2026-08-27
what it says
“Increasing the dosage beyond 100 mg a day is unlikely to produce any further benefit … Angina Pectoris … Some patients may require a dosage of 200 mg once a day for optimal effect”
NHS medicines A–Z — Atenolol, taking atenolol with other medicines, food and drink (reviewed 20 August 2026) · read 2026-08-27
what it says
“heart medicines, such as flecainide or digoxin … blood pressure medicines, such as clonidine or candesartan … NSAIDS, such as ibuprofen … insulin or other medicines for diabetes … decongestants … adrenaline”

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Updated 2026-08-29. Every line above traces to a numbered source. Kozen-X is not a medical device and does not give medical advice. It lists what published sources have written down — nothing more. A pair not listed is unrecorded, not cleared. Before you start, stop or re-time anything, talk to your doctor or pharmacist.

In Singapore

Classification
HSA register

prescription-only

This is the Singapore classification, taken from the HSA register. Dosing stays with the label and your pharmacist or doctor — this page never tells you how much to take.

What the label says

The SG urosin label (sin12330p) states the SAMe ceiling for both registered uses: in hypertension "50–100mg per day alone or in conjunction with other antihypertensive agents … Increasing the dosage more than 100mg is unlikely to produce more beneficial effects", and in angina pectoris "the dosage for most patients is 50–100mg once a day or in divided doses. Increasing the dosage more than 100mg is unlikely to produce more beneficial effects". the US tenormin label agrees for hypertension — "increasing the dosage beyond 100 mg a day is unlikely to produce any further benefit" — but adds for angina that "some patients may require a dosage of 200 mg once a day for optimal effect" — as directed on the label or by your doctor

Who should check first

Talk to a doctor or pharmacist before taking this if any of these apply to you.

Asthma or a history of obstructive airway disease: an SG label contraindication, and HealthHub: it may worsen or cause an asthma attack
Pre-diabetes or diabetes: HealthHub: it may hide symptoms of low blood sugar such as a fast heartbeat or tremors
Sinus bradycardia, heart block greater than first degree, cardiogenic shock or overt cardiac failure: SG label contraindications
Pregnant, planning pregnancy or breastfeeding: HealthHub asks that this be declared before starting

Documented interactions

With medicines and supplements

Heart medicines such as flecainide or digoxin: NHS lists these among medicines that may not mix well with atenolol¹³
Other blood pressure medicines such as clonidine or candesartan: NHS lists blood pressure medicines among those that may not mix well¹³
Insulin or other diabetes medicines: NHS lists these among medicines that may not mix well with atenolol¹³
NSAIDs such as ibuprofen: NHS lists non-steroidal anti-inflammatory drugs among medicines that may not mix well¹³
Decongestants and adrenaline: NHS lists medicines to clear a blocked nose, and adrenaline used in allergy treatment and anaesthetics¹³

Only combinations someone has written down appear here. A pair that is missing is unrecorded, not cleared.