BLOKIUM 50 MG TABLETS
SpainIt is used to treat high blood pressure (hypertension), prevent chest pain or tightness due to coronary problems (angina), regulate heartbeats in case of arrhythmias, and protect the heart during and after a heart attack.
Frequently asked questions
When should I not take this medication?
You must not take it if you are allergic to atenolol or any of its components, if you suffer from uncontrolled heart failure, a very slow pulse, heart blocks, sinus diseases, very low blood pressure, circulatory insufficiency, cardiogenic shock, untreated pheochromocytoma, or metabolic acidosis.
How should I take Blokium 50 mg?
The tablet should be swallowed whole with water, attempting to do so at the same time every day. The exact dose will be determined by your doctor according to your needs (for example, for hypertension, the usual dose is typically 100 mg or 50 mg per day).
What side effects can Blokium 50 mg cause?
Very common effects include fatigue, drowsiness, headache, insomnia, depression, difficulty breathing, and circulatory problems with cold extremities. Effects such as changes in blood pressure or pulse, confusion, muscle problems, altered vision, nausea, diarrhea, or changes in sexual desire may also occur.
What should I keep in mind if I take other medications?
It is important to inform your doctor if you take insulin, diabetes medications (sulfonylureas), other treatments for blood pressure or the heart, ibuprofen, adrenaline, or cold remedies. Some medications for blood pressure or migraines should not be discontinued without consulting a doctor.
What happens if I forget a dose or take too much?
If you forget a dose, take it as soon as you remember, but do not take a double dose to make up for it. If you take too much, you could experience difficulty breathing or a drop in pulse and blood pressure; in that case, contact your doctor or go to the hospital immediately.
Can I drive while taking this treatment?
Some people may feel dizzy or fatigued, so if you experience these symptoms, you should not drive vehicles or operate machinery.
Instructions for use
Package leaflet: Information for the user
Introduction
Package leaflet: information for the user
Blokium 50 mg tablets
atenolol
Read the entire leaflet carefully before you start taking this medicine, because it contains important information for you.
- Keep this leaflet as you may need to read it again.
- If you have any questions, ask your doctor or pharmacist.
- This medicine has been prescribed for you only, and you should not give it to other people, even if they have the same symptoms as you, because it could harm them.
- If you experience any adverse effects, consult your doctor or pharmacist, even if they are adverse effects not listed in this leaflet.
Leaflet contents
- What Blokium 50 mg is and what it is used for
- What you need to know before taking Blokium 50 mg
- How to take Blokium 50 mg
- Possible side effects
- How to store Blokium 50 mg
- Contents of the pack and other information
1. What Blokium 50 mg is and what it is used for
Blokium 50 mg belongs to a group of medicines called cardioselective adrenergic beta-blockers, which act preferentially on the heart.
Doctors prescribe this medicine for people with high blood pressure (hypertension), to prevent chest pain or tightness of coronary origin (angina), and to regulate heartbeats in arrhythmias. It also protects the heart during and after a heart attack (myocardial infarction).
2. What you need to know before taking Blokium 50 mg
Do not take Blokium 50 mg
-
if you are allergic to atenolol or to any of the other ingredients of this medicine (listed in section 6).
-
if you have had or currently have heart conditions such as: uncontrolled heart failure (when the heart does not pump enough blood to the rest of the body), bradycardia (very slow pulse), second- or third-degree atrioventricular block, or sick sinus syndrome (conditions in which the heartbeat is irregular).
-
if you have ever experienced very low blood pressure, circulatory failure, or cardiogenic shock.
-
if you have been diagnosed with phaeochromocytoma and are not being treated for it, or if you have metabolic acidosis.
Warnings and precautions
Talk to your doctor before starting to take this medicine.
- if you have any health problems such as asthma or breathing difficulties, diabetes, depression, circulatory disorders, heart problems other than those listed above, or kidney, liver, or thyroid problems.
- if you have been diagnosed with a type of chest pain called Prinzmetal's angina.
- if you have ever had an allergic reaction to anything, for example, an insect sting, you should be cautious when taking this medicine, as it may increase the severity of such allergic reactions.
- if you notice that your pulse becomes slower while taking these tablets. This is normal, but if you are concerned, inform your doctor.
- if you are diabetic, this medicine may mask symptoms of low blood sugar (hypoglycaemia), by reducing the usual response of increased pulse (heart rate). Atenolol may also increase the risk of severe hypoglycaemia when used with certain types of antidiabetic medicines called sulphonylureas (e.g., gliquidone, gliclazide, glibenclamide, glipizide, glimepiride or tolbutamide). Symptoms of hyperthyroidism or thyrotoxicosis (conditions in which thyroid hormone levels in the blood are elevated) may also be masked.
- if you are admitted to hospital, inform healthcare staff, and especially the anaesthetist, that you are being treated with this medicine, as certain medicines used during anaesthesia may be incompatible with Blokium.
If you have any doubts about any of the points above, consult your doctor before taking Blokium.
If you are undergoing any diagnostic tests (including blood and urine tests, skin tests using allergens, etc.), inform your doctor that you are taking this medicine, as it may affect test results. See section 4.
Other medicines and Blokium 50 mg
Tell your doctor or pharmacist if you are taking, have recently taken, or might need to take any other medicines.
Take special care and inform your doctor if you are taking insulin or oral antidiabetic medicines such as sulphonylureas (e.g., gliquidone, gliclazide, glibenclamide, glipizide, glimepiride or tolbutamide), disopyramide (for irregular heartbeats), other treatments for hypertension or angina (particularly verapamil, diltiazem, nifedipine, clonidine), treatment for heart failure (digoxin), indometacin or ibuprofen (for treatment of inflammation and/or pain), adrenaline (used in cardiac arrest or severe allergic reactions), or reserpine (for hypertension).
The use of other beta-blockers such as celiprolol, propranolol, metoprolol, timolol, bisoprolol, carvedilol, oxprenolol or nebivolol may increase the heart-depressant effect of atenolol (the active substance in this medicine).
You should also inform your doctor if you are taking any nasal decongestants or other cold remedies that you may have purchased over the counter.
If you are taking clonidine for hypertension or to prevent migraine, do not stop treatment with clonidine or this medicine without first consulting your doctor.
Never take any other medicine on your own initiative without medical advice, as some combinations should be avoided.
Pregnancy, breast-feeding and fertility
If you are pregnant or breast-feeding, think you may be pregnant, or are planning to become pregnant, consult your doctor or pharmacist before using this medicine.
The use of this medicine during breast-feeding is not recommended; if your doctor considers that you need to take it, it is advisable to switch from breast-feeding.
Children and adolescents
This medicine should not be used in children.
Use in patients over 65 years of age
Elderly patients have a higher risk of experiencing adverse reactions to this medicine, so it should be used with caution in these patients (see section 3).
Use in athletes
Athletes are advised that this medicine contains a component that may result in a positive doping test.
Driving and use of machines
Some people may occasionally experience dizziness and fatigue while taking this medicine. If you experience these effects, you should not drive or operate machinery.
This medicine contains less than 23 mg of sodium (1 mmol) per tablet; this is essentially "sodium-free".
3. How to take Blokium 50 mg
Follow exactly the instructions given by your doctor for taking this medicine. If in doubt, consult your doctor or pharmacist again.
Remember to take your medicine.
This medicine is for oral administration. Swallow the tablet whole with water.
Try to take your tablet at the same time each day.
Your doctor will determine the dose of this medicine you should take, based on your individual needs. The usual doses are:
Hypertension: The usual dose is generally 100 mg once daily. Some patients may require a maintenance dose of only 50 mg once daily. Assessment of response should only be made after 1 or 2 weeks of continuous treatment.
If blood pressure reduction is insufficient after this time, your doctor will consider the need to add a diuretic or another antihypertensive agent to the treatment.
Angina pectoris: The effective dose is generally 100 mg as a single dose or in two divided doses of 50 mg daily. Efficacy is generally not increased beyond this dose.
Arrhythmias: After initial treatment with intravenous atenolol, maintenance therapy may be started with 50 or 100 mg of atenolol orally, given as a single daily dose.
Acute myocardial infarction: During the early phase of a myocardial infarction, you may be hospitalized and given an intravenous dose of atenolol following the onset of chest pain. Subsequently, if no adverse effects occur, you should start taking this medicine orally as directed. The dose after this acute phase will be 100 mg daily by mouth. If adverse effects occur, such as a significant decrease in pulse and/or blood pressure, treatment will be discontinued.
Use in patients aged 65 years and older
Your doctor should adjust the dose of this medicine if you are over 65 years of age.
Use in patients with kidney disease
Your doctor should adjust the dose of this medicine if you have any kidney disease.
Use in patients with liver disease
Your doctor should adjust the dose of this medicine if you have any liver disease.
If you think that the effect of this medicine is too strong or too weak, inform your doctor or pharmacist.
If you take more Blokium 50 mg than you should
You may experience difficulty breathing or a decreased pulse or blood pressure. Contact your doctor or go to the nearest hospital as soon as possible. Take this leaflet with you.
In case of overdose or accidental ingestion, contact the Toxicology Information Service. Telephone 915 620 420.
If you forget to take Blokium 50 mg
If you forget to take your medicine, take a dose as soon as you remember. Do not take a double dose to make up for forgotten doses.
If you stop taking Blokium 50 mg
Your doctor will advise you on how long you should take this medicine. Do not stop taking the tablets before completing the treatment, even if you feel well, unless your doctor tells you otherwise. If your doctor advises you to stop taking this medicine, it should be discontinued gradually.
If you have any further questions about the use of this medicine, ask your doctor or pharmacist.
4. Possible adverse effects
Like all medicines, Blokium 50 mg may produce adverse effects, although not everyone will experience them.
If any of the following adverse effects occur, inform your doctor, who will advise you whether you should discontinue treatment and how to do so correctly.
The adverse effects observed with this medicine are as follows:
-
Very common (affects more than 1 in 10 patients): fatigue, numbness, headache, insomnia, depression, breathing difficulty (bronchospasm), circulatory problems, with cold extremities and tingling sensations.
-
Common (affects between 1 and 10 in 100 patients): severe circulatory disorders (reduction in blood pressure and/or pulse, cardiac block, heart failure), hallucinations, drowsiness, confusion, neurological disorders such as paresthesias (tingling and numbness in the extremities) or peripheral neuropathy (pain, loss of sensation, and inability to control muscles), muscle disorders, and visual disturbances.
-
Uncommon (affects between 1 and 10 in 1,000 patients): diarrhea, constipation, nausea, vomiting, abdominal cramps (abdominal pain), allergic reactions, skin rashes, itching, reversible hair loss, decreased platelets, decreased white blood cells, non-thrombocytopenic purpura (a blood disorder characterized by bruising and easy bleeding), increased eosinophils in blood, impotence (erectile dysfunction), decreased libido, pulmonary fibrosis, and pleural effusion.
Reporting of adverse effects
If you experience any type of adverse effect, consult your doctor, pharmacist, or nurse, even if it is a possible adverse effect not listed in this leaflet. You may also report them directly through the Spanish Pharmacovigilance System for Human Medicines: https://www.notificaram.es. By reporting adverse effects, you can help provide more information on the safety of this medicine.
5. Storage of Blokium 50 mg
Do not store above 30°C.
Keep this medicine out of the sight and reach of children.
Do not use this medicine after the expiry date stated on the container. The expiry date refers to the last day of the month indicated.
Medicines must not be disposed of via wastewater or household waste. Return any unused medicines and their containers to the pharmacy's SIGRE collection point
. If you are unsure, ask your pharmacist how to dispose of medicines and containers you no longer need. This will help protect the environment.
6. Contents of the container and additional information
Composition of Blokium 50 mg
- The active substance is atenolol. Each tablet contains 50 mg of atenol0l.
- The other components are microcrystalline cellulose (E-460), magnesium stearate (E-572), sodium starch glycolate (from potato), povidone.
Appearance of the medicine and contents of the pack
Blokium 50 mg tablets are white, round, flat, with a central groove on the upper side and a smooth lower side.
Blokium 50 mg tablets are available in packs containing 30 or 60 tablets.
Marketing Authorization Holder and Manufacturer
Marketing Authorization Holder
Almirall, S.A.
General Mitre, 151
08022 Barcelona (Spain)
Manufacturer
Industrias Farmacéuticas Almirall, S.A.
Ctra. de Martorell, 41-61
08740 Sant Andreu de la Barca - Barcelona (Spain)
This leaflet was approved in: April 2026
Detailed and up-to-date information on this medicine is available on the website of the Spanish Agency of Medicines and Health Products (AEMPS) http://www.aemps.gob.es/
Similar drugs
| Brand name | Dosage form | Active substance / Dosage | Manufacturer |
|---|---|---|---|
| ATENOLOL ALTER 100 MG TABLETS EFG | tablets |
|
Laboratorios Alter S.A. |
| ATENOLOL ALTER 50 MG TABLETS EFG | tablets |
|
Laboratorios Alter S.A. |
| ATENOLOL CINFA 100 MG TABLETS EFG | tablets |
|
Laboratorios Cinfa S.A. |
| ATENOLOL CINFA 50 MG TABLETS EFG | tablets |
|
Laboratorios Cinfa S.A. |
| BLOKIUM 100 MG TABLETS | tablets |
|
Almirall S.A. |
| TENORMIN 50 MG TABLETS | tablets |
|
Atnahs Pharma Netherlands Bv. |
The original data is available in the language of the country of manufacture.
Data source: Online Medicines Information Centre (CIMA) — AEMPS
Data last verified: September 21, 2026