{"ok":true,"entry":{"slug":"atenolol","kind":"medication","name":"atenolol","aliases":["Tenormin"],"brands_sg":["Prenolol","Tenol","Tenolol","Normaten","Urosin"],"class":"beta blocker","tags":["heart-bp"],"use_for":"sg label: hypertension and angina pectoris","use_after":"long-term use · healthhub: not stopped suddenly after weeks","use_duration":null,"take_with":"healthhub: with or without food","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"],"dose_note":"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","dosage":null,"ul_status":null,"sg_class":"prescription-only","cautions":["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"],"clashes":[{"src":["nhs_atenolol_int"],"note":"nhs lists these among medicines that may not mix well with atenolol","with":"heart medicines such as flecainide or digoxin"},{"src":["nhs_atenolol_int"],"note":"nhs lists blood pressure medicines among those that may not mix well","with":"other blood pressure medicines such as clonidine or candesartan"},{"src":["nhs_atenolol_int"],"note":"nhs lists these among medicines that may not mix well with atenolol","with":"insulin or other diabetes medicines"},{"src":["nhs_atenolol_int"],"note":"nhs lists non-steroidal anti-inflammatory drugs among medicines that may not mix well","with":"nsaids such as ibuprofen"},{"src":["nhs_atenolol_int"],"note":"nhs lists medicines to clear a blocked nose, and adrenaline used in allergy treatment and anaesthetics","with":"decongestants and adrenaline"}],"sources":[{"id":"hsa_register","url":"https://data.gov.sg/api/action/datastore_search?resource_id=d_767279312753558cbf19d48344577084&limit=6000","label":"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","quote":"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","accessed":"2026-08-27"},{"id":"ndf_urosin","url":"https://www.ndf.gov.sg/about-drugs/product-information/sin12330p/","label":"MOH National Drug Formulary (Singapore) — UROSIN FILM COATED TABLET 50 MG [SIN12330P], product information","quote":"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","accessed":"2026-08-27"},{"id":"ndf_atenolol_beacons","url":"https://www.ndf.gov.sg/about-drugs/product-information/sin08753p/","label":"MOH National Drug Formulary (Singapore) — ATENOLOL TABLET 50 MG [SIN08753P] (Beacons Pharmaceuticals), product information","quote":"ATENOLOL - 50 MG … Registration Number SIN08753P … Licence Holder BEACONS PHARMACEUTICALS PTE. LTD. … Forensic Classification PRESCRIPTION ONLY MEDICINES … ATC code C07AB03","accessed":"2026-08-27"},{"id":"ndf_urosin_ind","url":"https://www.ndf.gov.sg/about-drugs/product-information/sin12330p/","label":"MOH National Drug Formulary (Singapore) — UROSIN [SIN12330P], Indication(s)","quote":"Indication(s): Hypertension, angina pectoris","accessed":"2026-08-27"},{"id":"ndf_urosin_dose","url":"https://www.ndf.gov.sg/about-drugs/product-information/sin12330p/","label":"MOH National Drug Formulary (Singapore) — UROSIN [SIN12330P], Dosage and Administration: hypertension","quote":"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","accessed":"2026-08-27"},{"id":"ndf_urosin_dose2","url":"https://www.ndf.gov.sg/about-drugs/product-information/sin12330p/","label":"MOH National Drug Formulary (Singapore) — UROSIN [SIN12330P], Dosage and Administration: angina pectoris","quote":"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","accessed":"2026-08-27"},{"id":"ndf_urosin_ci","url":"https://www.ndf.gov.sg/about-drugs/product-information/sin12330p/","label":"MOH National Drug Formulary (Singapore) — UROSIN [SIN12330P], Contraindication(s)","quote":"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","accessed":"2026-08-27"},{"id":"healthhub_atenolol","url":"https://www.healthhub.sg/medication-devices-and-treatment/medications/atenolol","label":"HealthHub (MOH Singapore) — Atenolol, medication information leaflet","quote":"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","accessed":"2026-08-27"},{"id":"healthhub_atenolol_prec","url":"https://www.healthhub.sg/medication-devices-and-treatment/medications/atenolol","label":"HealthHub (MOH Singapore) — Atenolol, precautions","quote":"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","accessed":"2026-08-27"},{"id":"healthhub_atenolol_se","url":"https://www.healthhub.sg/medication-devices-and-treatment/medications/atenolol","label":"HealthHub (MOH Singapore) — Atenolol, common side effects","quote":"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","accessed":"2026-08-27"},{"id":"fda_tenormin","url":"https://api.fda.gov/drug/label.json?search=openfda.brand_name:%22TENORMIN%22&limit=3","label":"TENORMIN (atenolol) tablets — US prescribing information, openFDA drug label record (Upsher-Smith Laboratories, LLC)","quote":"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","accessed":"2026-08-27"},{"id":"fda_tenormin_dose","url":"https://api.fda.gov/drug/label.json?search=openfda.brand_name:%22TENORMIN%22&limit=3","label":"TENORMIN (atenolol) tablets — US prescribing information, Dosage and Administration: hypertension and angina ceilings","quote":"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","accessed":"2026-08-27"},{"id":"nhs_atenolol_int","url":"https://www.nhs.uk/medicines/atenolol/","label":"NHS medicines A–Z — Atenolol, taking atenolol with other medicines, food and drink (reviewed 20 August 2026)","quote":"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","accessed":"2026-08-27"}],"brand_certs":null,"updated_at":"2026-08-29T16:16:10.48466+08:00"},"disclaimer":"kozen-x is not a medical device and does not give medical advice. it lists what published sources have written down. absence of a record is not the same as safe."}