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Terms Of Use


Brand Name(s) : Tenoret 50, Tenoretic
Side Effects


Co-tenidone should be used with caution in:

It should not be used in:

Also see list of precautions and interactions


Do not store above 25ºC.


What is it used for?

Listed below are the typical uses of co-tenidone.

On occasion your doctor may prescribe this medicine to treat a condition not on the above list.


How often do I take it?

  • Take this medication by mouth usually once daily, preferably first thing in the morning, with or without food. Swallow your tablets whole with a drink of water.
  • Use this medication regularly in order to get the most benefit from it.
  • Remember to use it at the same time each day - unless specifically told not to by your doctor.
  • It may take up to some days before the full benefit of this drug takes effect.
  • Certain medical conditions may require different dosage instructions as directed by your doctor.

What dose?

  • Dosage is based on your age, gender, medical condition, response to therapy, and use of certain interacting medicines.

Do I need to avoid anything?

  • Co-tenidone is unlikely to affect you being able to drive or operate machinery. However, you may feel dizzy or tired while taking this medicine. Therefore, you should wait to see how your medicine affects you before driving or operating machinery. Consult your doctor or pharmacist for more details.

When can I stop?

  • It is important to continue taking this medication even if you feel well, unless your doctor tells you to stop.


  • Cold hands and feet
  • Slow pulse rate
  • Diarrhoea
  • Feeling sick
  • Feeling tired
  • High levels of sugar in the blood
  • Low levels of sodium in the blood which may cause weakness, being sick and cramps
  • Low levels of potassium in the blood
  • Increase in the amount of uric acid in the blood
  • Disturbed sleep
  • Heart block
  • Numbness and spasm in the fingers which is followed by warmth (Raynaud's disease)
  • Dizziness
  • Headache
  • Feeling confused
  • Changes in personality
  • Imagining that you can see and hear things that aren't really there (hallucinations)
  • Mood changes
  • Nightmares
  • Dry mouth
  • Hair thinning
  • Dry eyes
  • Skin rash
  • Tingling of the hands
  • Problems with eyesight
  • Bruising more easily or purplish marks on the skin
  • Unable to get an erection (impotence)

If any of these persist or you consider them severe then inform your doctor or pharmacist.

Further information about other side effects can be found in the patient information leaflet.

Tell your doctor immediately if you develop any of the following symptoms:

  • Raised lumps on your skin or swelling of your face, lips, mouth, tongue or throat (this may be a sign of an allergic reaction).

Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.

A serious allergic reaction to this drug is unlikely, but seek immediate medical attention if it occurs. Symptoms of a serious allergic reaction include: rash, itching/swelling (especially of the face/tongue/throat), dizziness, trouble breathing.

This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.

The Yellow Card Scheme allows you to report suspected side effects from any type of medicine (which includes vaccines, herbals and over the counter medicines) that you are taking. It is run by the medicines safety watchdog called the Medicines and Healthcare products Regulatory agency (MHRA). Please report any suspected side effect on the Yellow Card Scheme website.


Before taking co-tenidone, tell your doctor or pharmacist if you are allergic to it; or to other beta-blockers or water tablets (diuretics); or if you have any other allergies.

This medication should not be used if you have certain medical conditions. Before using this medicine, consult your doctor or pharmacist in case of: breathing problems including wheezing, asthma or similar, a history of lung disease including asthma or wheezing, severe liver or kidney disease, an allergy to co-tenidone, atenolol or chlortalidone or to any other ingredients in the medicine, heart failure which is not under control, second- or third-degree heart block which may be treated by a pacemaker, slow or uneven heart rate, the heart condition cardiogenic shock, a type of chest pain (angina) called Prinzmetal's angina, disturbance of blood potassium levels or any disturbance of other blood electrolytes (salts) including sodium or calcium, very low blood pressure or very poor circulation, a type of tumour called a phaeochromocytoma that is not being treated, unusually high levels of acid in your blood (metabolic acidosis), abnormal heart rhythm (sick sinus syndrome), symptoms caused by high levels of uric acid in the blood, disease of the adrenal glands (Addison's disease), you are pregnant, breast feeding or are trying to become pregnant.

Before using this medication tell your doctor or pharmacist your medical history, especially any of the following history of allergy e.g. to insect stings, liver or kidney disease, the skin condition psoriasis, poor blood circulation, heart failure that is controlled, first-degree heart block, high blood sugar (diabetes), overactive thyroid (thyrotoxicosis), low potassium diet, stomach upsets, the muscle condition myasthenia gravis, you are taking digitalis medicines such as digoxin.

Before having surgery, tell your doctor or dentist that you are taking this medication.

Does alcohol intake affect this drug?

  • You should avoid alcohol while taking this medicine.

The elderly: co-tenidone should be used with caution in the elderly as it may cause low potassium levels (hypokalaemia)

Pregnancy and breastfeeding - please ensure you read the detailed information below


Co-tenidone is not safe to take if you are, or are planning to become, pregnant.

It is sensible to limit use of medication during pregnancy whenever possible. However, your doctor may decide that the benefits outweigh the risks in individual circumstances and after a careful assessment of your specific health situation.

If you have any doubts or concerns you are advised to discuss the medicine with your doctor or pharmacist.


Co-tenidone is not safe to take if you are breastfeeding.

It is sensible to limit use of medication during breastfeeding whenever possible. However, your doctor may decide that the benefits outweigh the risks in individual circumstances and after a careful assessment of your specific health situation.

If you have any doubts or concerns you are advised to discuss the medicine with your doctor or pharmacist.


Before using this medicine, tell your prescriber of all the medicines you are taking including prescription medicines and medicines you have bought over the counter without a prescription. Tell your prescriber if you are taking vitamins or complementary remedies such as herbal products, as these can also interact with medicines.

If you are taking more than one medicine, these may interact with each other. Your prescriber may decide to use medicines which interact with each other if the benefit outweighs the risks. In these cases, the dose of your medicines may need to be adjusted or you may be monitored more closely.

The following medicines may interact with co-tenidone:

  • Verapamil
  • Diltiazem
  • Lithium
  • Other medicines for high blood pressure
  • ACE inhibitors
  • Adrenergic neurone blockers
  • Alcohol
  • Aldesleukin
  • Alpha blockers
  • Alprostadil
  • Angiotensin II receptor antagonists
  • Amiodarone
  • Medicines for abnormal heart rhythm (anti-arrhythmics)
  • Medicines for anxiety
  • Medicines to help you sleep (hypnotics)
  • Baclofen
  • Calcium channel blockers
  • Acetazolamide
  • Allopurinol
  • Amphotericin
  • Amisulpride
  • Atomoxetine
  • Medicines for depression
  • Calcium salts
  • Carbamazepine
  • Chlorpropamide
  • Ciclosporin
  • Colestipol
  • Colestyramine
  • Dobutamine
  • Hydralazine
  • Ketorolac
  • Limecycline
  • Clonidine
  • Levodopa
  • Monoamine-oxidase inhibitors (MAOIs)
  • Mefloquine
  • Methyldopa
  • Minoxidil
  • Moxonidine
  • Phenothiazines
  • Pimozide
  • Platinum drugs
  • Sertindole
  • Digoxin
  • Ergotamine
  • Flecainide
  • Methysergide
  • Corticosteroids
  • Water tablets
  • Diazoxide
  • Disopyramide
  • Adrenaline (also known as epinephrine)
  • Ibuprofen
  • Reboxetine
  • Sotalol
  • Beta2-agonists such as salbutamol
  • Moxisylyte
  • Lidocaine (also known as lignocaine)
  • Nifedipine
  • Medicines for diabetes including insulin
  • Non-steroidal anti-inflammatory drugs (NSAIDs) including indometacin
  • Medicines to treat nose or sinus congestion or other cold remedies (including those that can be bought from pharmacies)
  • Anaesthetics
  • Nitrates
  • Oestrogens
  • Phenothiazines
  • Pilocarpine
  • Sodium nitroprusside
  • Theophylline
  • Toremifine
  • Vitamin D
  • Tizanidine

This information does not contain all possible interactions. Therefore, tell your prescriber of all the products you are using before taking this medicine.

If you have a question or want to discuss anything about your medicine, speak to your local pharmacist.


Taking too much co-tenidone may cause the following: slow heart rate, low blood pressure (hypotension), dizziness, heart problems and difficulty breathing (bronchospasm).

People who have taken too much co-tenidone, should talk to a doctor or go to a hospital straightaway. Take the medicine pack with you so that the tablets can be identified.

If you think you, or someone you care for, might have accidentally taken more than the recommended dose of co-tenidone or intentional overdose is suspected, contact your local hospital, GP or if in England call 111. In Scotland call NHS 24. In Wales, call NHS Direct Wales. In the case of medical emergencies, always dial 999.


If you miss a dose, take it as soon as you remember. If it is near the time of the next dose, skip the missed dose and resume your usual dosing schedule. Do not double the dose to catch up.

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Source: Selected from data included with permission and copyrighted by Boots UK Limited. This copyrighted material is sourced from a licensed data provider and is not for distribution, except as may be authorised by the applicable terms of use.
CONDITIONS OF USE: The information in this database is intended to supplement, not substitute for, the expertise and judgement of healthcare professionals. The information is not intended to cover all possible uses, directions, precautions, drug interactions or adverse events, nor should it be construed to indicate that use of a particular medicine is safe, appropriate or effective for you or anyone else. A healthcare professional should be consulted before taking any medicine, changing any diet, or discontinuing any course of treatment.

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