Patient leaflets and SmPCs, drug interaction checker, official dosages and NHS pharmacy opening hours — all in one place.
Patient leaflets and SmPCs, drug interaction checker, official dosages and NHS pharmacy opening hours — all in one place.
The electronic medicines compendium (emc) no longer publishes a Summary of Product Characteristics for this product, which usually means it is no longer marketed in the UK. The patient leaflet below is kept for reference, but the product may not be available.
If you were prescribed this medicine, other products containing Atenolol, Chlortalidone may still be available. Do not stop your treatment — ask your pharmacist or GP what to use instead.
for Co-tenidone is used to treat high blood pressure (hypertension). It contains two different medicines atenolol and chlortalidone. These medicines work together to lower your blood pressure.
e Co-Tenidone tablets Do not take Co-Tenidone tablets:
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Warnings and precautions Talk to your doctor before taking Co-tenidone tablets:
Co-Tenidone tablets Always take this medicine exactly as your doctor or pharmacist has told you. Check with your doctor if you are not sure.
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PRODUCT : CUSTOMER : FP CODE: PLANT LOCATION : DIMENSIONS : PHARMACODE No. : SAP CODE No. : TEXT FONT SIZE : FILE NAME : SOFTWARE : TYPEFACES : ARTWORK (DETAILS) RECEIVED ON : PROOF REVISION :
Co-Tenidone 50/12.5mg & 100/25mg – 28 Tabs Wockhardt UK FP1682; FP1683 Daman (Bhimpore) (w)148 x (h)420mm 2870 229237 (PREVIOUS VERSION SAP CODE No. : 228914) 9 pt. Co-tenidone_Leaflet_108040-4.ai Adobe Illustrator CS6 Myriad Pro Regular / Bold 21st & 22nd January, 2026 R 1st PDF sent on – 22ND JAN. 2026 R 2nd PDF sent on – 11TH FEB. 2026
CHANGE CONTROL : Version changes due to change in: Size/Layout Regulatory Changes in detail: • New regulatory text
Non-Regulatory
Your doctor may take blood samples every so often to check on these levels. Uncommon (may affect up to 1 in 100 people)
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The other ingredients are: maize starch, calcium hydrogen phosphate, microcrystalline cellulose, povidone K30, sodium starch glycollate, magnesium stearate and purified water. Film coating: opadry OY-6954. What Co-Tenidone tablets look like and the contents of the pack Co-Tenidone tablets are brownish pink, round, biconvex film-coated tablets marked CTE 50 or CTE 100 on one side and CP on the other. These tablets are available in blister packs of white opaque PVC film and hard tempered aluminium foil. They are available in the pack size of 28, 30, 56 and 60. Not all pack sizes may be marketed. Marketing Authorisation Holder: Wockhardt UK Ltd, Ash Road North, Wrexham, LL13 9UF, UK. Manufacturer: CP Pharmaceuticals Ltd, Ash Road North, Wrexham, LL13 9UF, UK. Other formats: To listen to or request a copy of this leaflet in Braille, large print or audio please call, free of charge: 0800 198 5000 (UK Only).
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What Co-tenidone Tablets contain The active ingredients are: atenolol and chlortalidone.
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not listed in this leaflet. You can also report side effects directly via the Yellow Card Scheme Website: www.mhra.gov.uk/yellowcard or search for MHRA Yellow Card in the Google Play or Apple App Store.
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If you stop taking Co-tenidone tablets Do not stop taking Co-tenidone tablets without talking to your doctor. In some cases, you may need to stop taking it gradually.
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If you forget to take Co-Tenidone tablets If you forget to take a dose, take it as soon as you remember. However, if it is almost time for the next dose, skip the missed dose. Do not take a double dose to make up for a forgotten dose.
Conditions that may get worse If you have any of the following conditions, they may get worse when you start to take your medicine. This happens rarely affecting up to 1 in 1,000 people:
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If you take more Co-Tenidone tablets than you should If you take more Co-tenidone tablets than prescribed by your doctor, talk to a doctor or go to a hospital straight away. Take the medicine pack with you so that the tablets can be identified.
Please be ready to give the following information: Product Name
Reference number
Co-Tenidone 100/25mg Tablets
29831/0056
Co-Tenidone 50/12.5mg Tablets
29831/0057
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Use in Children Your medicine must not be given to children.
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People with kidney problems If you have problems with your kidneys, your doctor may give you a lower dose or ask you to take this medicine less often.
This is a service provided by the Royal National Institute of Blind People. This leaflet was last revised in 01/2026.
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Adults The recommended dose for an adult is one tablet each day.
Not known (frequency cannot be estimated from the data available)
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Co-Tenidone tablets
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Allergic reactions: If you have an allergic reaction, see a doctor straight away. The signs may include raised lumps on your skin (weals) or swelling of your face, lips, mouth, tongue or throat.
By reporting side effects you can help provide more information on the safety of this medicine.
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Like all medicines, this medicine can cause side effects, although not everybody gets them.
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4. Possible side effects
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If you have any further questions on the use of this medicine, ask your doctor or pharmacist.
Reporting of side effects If you get any side effects, talk to your doctor, pharmacist or nurse. This includes any
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Do not throw away any medicines via wastewater or household waste. Ask your pharmacist how to throw away medicines you no longer use. These measures will help protect the environment.
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Common (may affect up to 1 in 10 people)
Keep out of the sight and reach of children.
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Other possible side effects:
Co-tenidone 50/12.5mg Film-Coated Tablets comes as tablet containing 12.5mg. Always follow the dose your doctor or pharmacist has given you, and read the leaflet that comes with the medicine.
The active substance in Co-tenidone 50/12.5mg Film-Coated Tablets is atenolol, chlortalidone.
This leaflet reproduces the patient information leaflet approved for Co-tenidone 50/12.5mg Film-Coated Tablets, as published on the electronic medicines compendium (emc). The version printed inside your medicine’s packaging is the one that applies to you.
Whether a medicine is available over the counter or on prescription only depends on its licence. Check the leaflet, or ask your pharmacist — they can tell you straight away.
The text above reproduces the patient information leaflet approved for this medicine, restructured for easier reading.
The management of hypertension, particularly suited to older patients.
Posology
Adults:
One tablet daily.
Elderly:
One tablet daily. The elderly with hypertension who do not respond to low dose therapy with a single agent should have a satisfactory response to a single tablet daily of co-tenidone. Where hypersensitive control is not achieved, addition of a small dose of a third agent e.g. as a vasodilator, may be appropriate.
Paediatric population:
The use of co-tenidone is not recommended in children. The safety and efficacy of co-tenidone in children has not yet been established.
Renal impairment:
Due to the properties of the chlortalidone component, Co-tenidone has reduced efficacy in the presence of renal insufficiency. This fixed dose combination should thus not be administered to patients with severe renal impairment (see section 4.3).
Method of administration
Oral administration.
Co-tenidone should not be used in the following:
• hypersensitivity to the active substances (or to sulphonamide derived medicinal products) or to any of the excipients listed in section 6.1
• bradycardia
• cardiogenic shock
• hypotension
• metabolic acidosis
• severe peripheral arterial circulatory disturbances
• second- or third-degree heart block
• sick sinus syndrome
• untreated phaeochromocytoma
• severe renal failure
• uncontrolled heart failure
Co-tenidone tablets must not be given during pregnancy or lactation.
Due to its beta-blocker component Co-tenidone tablets:
• although contraindicated in uncontrolled heart failure (see section 4.3) may be used in patients whose signs of heart failure have been controlled. Caution must be exercised in patients whose cardiac reserve is poor.
• may increase the number and duration of angina attacks in patients with Prinzmetal's angina due to unopposed alpha receptor mediated coronary artery vasoconstriction. Atenolol is a beta-1 selective beta-blocker; consequently the use of Co-tenidone may be considered although utmost caution must be exercised.
• although contraindicated in severe peripheral arterial circulatory disturbances (see section 4.3) Co-tenidone may also aggravate less severe peripheral arterial circulatory disturbances.
• due to its negative effect on conduction time, caution must be exercised if it is given to patients with first degree heart block.
• may modify warning signs of hypoglycaemia as tachycardia, palpitation and sweating. Beta-blockers could further increase the risk of severe hypoglycaemia when used concurrently with sulfonylureas. Diabetic patients should be advised to carefully monitor blood glucose levels. (see Section 4.5).
• may mask the cardiovascular signs of thyrotoxicosis.
• will reduce heart rate, as a result of its pharmacological action. In the rare instances when a treated patient develops symptoms which may be attributable to a slow heart rate, the dose may be reduced.
• should not be discontinued abruptly in patients suffering from ischaemic heart disease.
• may cause a more severe reaction to a variety of allergens, when given to patients with a history of anaphylactic reaction to such allergens. Such patients may be unresponsive to the usual doses of adrenaline used to treat the allergic reactions.
• may cause a hypersensitivity reaction including angioedema and urticaria
• patients with bronchospastic disease should, in general, not receive beta blockers due to increasing in airways resistance. Atenolol is a beta1-selective beta-blocker, however this selectivity is not absolute. Therefore the lowest possible dose of Co-tenidone should be used and utmost caution must be exercised. If increased airways resistance does occur, Co-tenidone should be discontinued and bronchodilator therapy (eg salbutamol) administered if necessary.The label and patient information leaflet for this product state the following warning: “Do not take this medicine if you have a history of wheezing or asthma.”
• systemic effects of oral beta-blockers may be potentiated when used concomitantly with ophthalmic beta-blockers.
• in patients with pheochromocytoma Co-tenidone must be administered only after alfa-receptor blockade. Blood pressure should be monitored closely.
• caution must be exercised when using anaesthetic agents with Co-tenidone. The anaesthetist should be informed and the choice of anaesthetic should be an agent with as little negative inotropic activity as possible. Use of beta-blockers with anaesthetic drugs may result in attenuation of the reflex tachycardia and increase the risk of hypotension. Anaesthetic agents causing myocardial depression are best avoided.
• Co-tenidone should be used with caution in patients with a predisposition to uricaemia or gout since chlorthalidone may cause a rise in serum uric acid levels. Prolonged elevation can be corrected by the use of a uricosuric agent.
Due to its chlortalidone component:
• plasma electrolyte should be periodically determined in appropriate intervals to detect possible electrolyte imbalance especially hypokalaemia and hyponatraemia.
• hypokalaemia and hyponatraemia may occur. Measurement of electrolytes is recommended, especially in the older patient, those receiving digitalis preparations for cardiac failure, those taking an abnormal (low in potassium) diet or those suffering from gastrointestinal complaints. Hypokalaemia may predispose to arrhythmias in patients receiving digitalis.
• impaired glucose tolerance may occur and diabetic patients should be aware of the potential for increased glucose levels. Close monitoring of glycaemia is recommended in the initial phase of therapy and in prolonged therapy test for glucosuria should be carries out at regular intervals.
• in patients with impaired hepatic function or progressive liver disease, minor alterations in fluid and electrolyte balance may precipitate hepatic coma.
• hyperuricaemia may occur. Only a minor increase in serum uric acid usually occurs but in cases of prolonged elevation, the concurrent use of a uricosuric agent will reverse the hyperuricaemia.
• Choroidal effusion, acute myopia and secondary angle-closure glaucoma:
Sulfonamide or sulfonamide derivative drugs can cause an idiosyncratic reaction resulting in choroidal effusion with visual field defect, transient myopia and acute angle-closure glaucoma. Symptoms include acute onset of decreased visual acuity or ocular pain and typically occur within hours to weeks of drug initiation. Untreated acute angle-closure glaucoma can lead to permanent vision loss. The primary treatment is to discontinue drug intake as rapidly as possible. Prompt medical or surgical treatments may need to be considered if the intraocular pressure remains uncontrolled. Risk factors for developing acute angle-closure glaucoma may include a history of sulfonamide or penicillin allergy.
This medicine contains less than 1 mmol sodium (23mg) per tablet, that is to say essentially 'sodium-free'.
Due to atenolol:
Combined use of beta-blockers and calcium channel blockers with negative inotropic effects, e.g. verapamil, diltiazem, can lead to an exaggeration of these effects particularly in patients with impaired ventricular function and/or sino-atrial or atrio-ventricular conduction abnormalities. This may result in severe hypotension, bradycardia and cardiac failure. Neither the beta-blocker nor the calcium channel blocker should be administered intravenously within 48 hours of discontinuing the other.
Class I anti-arrhythmic drugs (e.g. disopyramide) and amiodarone may have a potentiating effect on atrial-conduction time and induce negative inotropic effect.
Digitalis glycosides, in association with beta-blockers, may increase atrio-ventricular conduction time.
Beta-blockers may exacerbate the rebound hypertension which can follow the withdrawal of clonidine. If the two drugs are co-administered, the beta-blocker should be withdrawn several days before discontinuing clonidine. If replacing clonidine by beta-blocker therapy, the introduction of beta-blockers should be delayed for several days after clonidine administration has stopped.
Concomitant use of sympathomimetic agents, e.g. adrenaline (epinephrine), may counteract the effect of beta-blockers.
Concomitant use of prostaglandin synthetase-inhibiting drugs e.g. ibuprofen and indomethacin, may decrease the hypotensive effects of beta-blockers.
Caution must be exercised when using anaesthetic agents with Co-tenidone tablets (see section 4.4).
Concomitant use with insulin and oral antidiabetic drugs may lead to the intensification of the blood sugar lowering effects of these drugs. The concomitant use of beta-blockers with sulfonylureas could increase the risk of severe hypoglycaemia. Symptoms of hypoglycaemia, particularly tachycardia, may be masked (see section 4.4).
Due to chlortalidone:
The chlortalidone component may reduce the renal clearance of lithium leading to increased serum concentrations. Dose adjustments of lithium may therefore be necessary.
Concomitant use with insulin and oral antidiabetic drugs may lead to the intensification of the blood sugar lowering effects of these drugs.
Due to the combination product:
Concomitant therapy with dihydropyridines e.g. nifedipine, may increase the risk of hypotension, and cardiac failure may occur in patients with latent cardiac insufficiency.
Concomitant use of baclofen may increase the antihypertensive effect making dose adjustments necessary.
Fertility:
No data on fertility available.
Pregnancy:
Co-tenidone tablets must not be given during pregnancy.
Lactation:Co-tenidone tablets must not be given during lactation.
Use is unlikely to result in any impairment of the ability of patients to drive or use machinery. However, it should be taken into account that occasionally dizziness or fatigue may occur.
Tabulated list of adverse reactions
Co-tenidone tablets were well tolerated in clinical studies, the undesired events reported are usually attributable to the pharmacological actions of its components.
The following undesired events, listed by body system, have been reported with the following frequencies: Very common (≥1/10), common (≥1/100 to <1/10), uncommon (≥1/1,000 to <1/100 ), rare (≥1/10,000 to <1/1,000 ), very rare (<1/10,000), not known (cannot be estimated from available data):
System Organ Class
Frequency
Adverse Drug Reaction
Blood and lymphatic system disorders
Rare
Purpura, thrombocytopenia, leucopenia (related to chlortalidone)
Psychiatric disorders
Uncommon
Sleep disturbances of the type noted with other beta blockers
Rare
Mood changes, nightmares, confusion, psychoses and hallucinations
Nervous system disorders
Rare
Dizziness, headache, paraesthesia
Not known
Depression
Eye disorders
Rare
Dry eyes, visual disturbances
Not Known
Choroidal effusion
Cardiac disorders
Common
Bradycardia
Rare
Heart failure deterioration, precipitation of heart block
Vascular disorders
Common
Cold extremities
Rare
Postural hypotension which may be associated with syncope, intermittent claudication may be increased if already present, in susceptible patients Raynaud's phenomenon
Respiratory, thoracic and mediastinal disorders
Rare
Bronchospasm may occur in patients with bronchial asthma or a history of asthmatic complaints
Gastrointestinal disorders
Common
Gastrointestinal disturbances (including nausea related to chlortalidone)
Rare
Dry mouth
Not known
Constipation
Hepatobiliary disorders
Rare
Hepatic toxicity including intrahepatic cholestasis, pancreatitis (related to chlortalidone)
Skin and subcutaneous tissue disorders
Rare
Alopecia, psoriasiform skin reaction, exacerbation of psoriasis, skin rashes
Not known
Hypersensitivity reactions, including angioedema and urticaria
Musculoskeletal and connective tissue disorders
Not known
Lupus-like syndrome
Reproductive system and breast disorders
Rare
Impotence
General disorders and administration site conditions
Common
Fatigue
Investigations
Common
Related to chlortalidone: Hyperuricaemia, hyponatraemia, hypokalaemia, impaired glucose tolerance
Uncommon
Elevations of transaminase levels.
Very rare
An increase in ANA (Antinuclear Antibodies) has been observed, however the clinical relevance of this is not clear
Cases of choroidal effusion with visual field defect have been reported after the use of thiazide and thiazide-like diuretics.
Discontinuation of Co-tenidone should be considered if, according to clinical judgement, the well-being of the patient is adversely affected by any of the above reactions.
Reporting of suspected adverse reactions
Reporting suspected adverse reactions after authorisation of the medicinal product is important. It allows continued monitoring of the benefit/risk balance of the medicinal product. Healthcare professionals are asked to report any suspected adverse reactions via the Yellow Card Scheme. Website: www.mhra.gov.uk/yellowcard or search for MHRA Yellow Card in the Google Play or Apple App Store.
The symptoms of overdosage may include bradycardia and hypotension, acute cardiac insufficiency and bronchospasm.
General treatment should include: close supervision, treatment in an intensive care ward, the use of gastric lavage, activated charcoal and a laxative to prevent absorption of any drug still present in the gastrointestinal tract, the use of plasma or plasma substitutes to treat hypotension and shock. The possible use of haemodialysis or haemoperfusion may be considered.
Excessive bradycardia may be countered by atropine 1-2 mg intravenously and/or a cardiac pacemaker. If necessary, this may be followed by a bolus dose of glucagon 10mg intravenously. If required, this may be repeated or followed by an intravenous infusion of glucagon 1-10mg/hour depending on response. If no response to glucagon occurs or if glucagon is unavailable, a beta adrenoceptor stimulant such as dobutamine 2.5 to 10 micrograms/kg/minute by intravenous infusion may be given.
Dobutamine, because of its positive inotropic effect, could be used to treat hypotension and acute cardiac insufficiency. It is likely that these doses would be inadequate to reverse the cardiac effects of beta-blocker blockade if a large overdose has been taken. The dose of dobutamine should therefore be increased if necessary to achieve the required response according to the clinical condition of the patient.
Bronchospasm can usually be reversed by bronchodilators.
Excessive diuresis should be countered by maintaining normal fluid and electrolyte balance.
Medicines sold in Romania with the same active substance: Cunoscut în România ca
⚠ Not the same combination. This medicine contains Atenolol, Chlortalidone. The products below do not contain exactly the same set of active substances — they are not direct substitutes.
Some of these do not contain exactly the same active substances — check each one. The strength, the form and whether you need a prescription can differ. Always ask a pharmacist before you switch. Romanian medicines in the UK →
Medicines sold in Poland with the same active substance: W Polsce znany jako
⚠ Not the same combination. This medicine contains Atenolol, Chlortalidone. The products below do not contain exactly the same set of active substances — they are not direct substitutes.
Some of these do not contain exactly the same active substances — check each one. The strength, the form and whether you need a prescription can differ. Always ask a pharmacist before you switch. Polish medicines in the UK →
Ask anything about Co-tenidone 50/12.5mg Film-Coated Tablets. The assistant answers only from this leaflet — if the leaflet does not cover it, it will say so. It does not give medical advice.
Answers come from the patient leaflet published on the electronic medicines compendium (emc). They are not medical advice. Ask a pharmacist or your GP if you are unsure. For urgent help call NHS 111, or 999 in an emergency.
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