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Active substance(s): ATENOLOL / CHLORTALIDONE

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Co-tenidone 50/12.5mg and 100/25mg
(atenolol and chlortalidone)

Read all of this leaflet carefully before you start taking this medicine.
• Keep this leaflet. You may need to read it again.
• If you have any further questions, ask your doctor or pharmacist.
• This medicine has been prescribed for you. Do not pass it on to others. It may harm them, even if their
symptoms are the same as yours.

1 What Co-tenidone tablets are and what they are used for
2 Before you take
3 How to take
4 Possible side effects
5 How to store
6 Further information
1 What Co-tenidone tablets are and what they are used for
Co-tenidone tablets may be used to control high blood pressure.

2 Before you take

Do not take Co-tenidone tablets and tell your doctor if you have:

• an allergy (hypersensitivity) to atenolol, chlortalidone, sulfonamide derived medicines or any of the other
ingredients in Co-tenidone tablets (see section 6)
• second or third degree heart block
• shock caused by heart problems
• cramping pains causing limping (intermittent claudication)
• severe kidney or liver failure.
• breathing problems (reversible obstructive airways disease) e.g. asthma or bronchitis. Do not take this medicine
if you have a history of wheezing or asthma. Consult your doctor or pharmacist first
• heart failure which is not under control
• a slow heart rate
• low blood pressure
• severe blood circulation problems (which may cause your fingers and toes to tingle or turn pale or blue)
• an increased acidity of the blood (metabolic acidosis)
• untreated phaeochromocytoma (high blood pressure due to a tumour near the kidney)
• heart conduction or rhythm problems (sick sinus syndrome)
• are pregnant or breastfeeding

Take special care with Co-tenidone tablets and tell your doctor if you:

have a tight, painful feeling in the chest in periods of rest (Prinzmetal’s angina)
have poor liver function/liver disease
have first degree heart block
have poor heart function
have heart disease or failure
have diabetes mellitus
have stomach or intestine problems causing a loss of potassium from the body
have or have had high levels of uric acid in the blood, gout or severe joint pain
are on a low-potassium diet
are elderly
have a history of allergic reactions

suffer from treated phaeochromocytoma (high blood pressure due to a tumour near the kidney)
have any thyroid problems
have problems with blood circulation
will be undergoing surgery where an anaesthetic will be used

 use beta-blocker eye-drops.
Taking other medicines

Before taking Co-tenidone tablets, tell your doctor if you are taking or have recently taken any of the
following medicines, or are taking any non-prescribed medicines.
• adrenaline (epinephrine, used in anaphylactic shock)
• amphetamines
• sympathomimetic agents (in decongestant, asthma or heart medicines)
• ergotamine (to treat migraines)
• anti-arrhythmic drugs (to treat irregular heart beats)
• clonidine (to treat high blood pressure)
• nifedipine and verapamil (to treat heart diseases)
• aluminium hydroxide (in indigestion remedies)
• medicines containing calcium
• chemotherapy drugs (to treat cancer)
• medicines to treat diabetes
• lithium (for psychiatric disorders)
• cardiac glycosides e.g. digoxin and digitoxin (to treat heart conditions)
• aminoglycosides
• indomethacin, ibuprofen (Non-Steroidal Anti-Inflammatory Drugs (NSAIDs))
• anaesthetics
• tubocurarine, baclofen (muscle relaxants)

Pregnancy and breast feeding

Co-tenidone tablets are not recommended during pregnancy or breast feeding. Ask your doctor or pharmacist for
advice before taking any medicine.

Driving and using machines

Co-tenidone tablets may cause you to have low blood pressure (dizziness, tiredness and lightheadedness) or a slow
heart beat. Make sure you are not affected before driving or operating machinery.


During long-term treatment your doctor may want to carry out tests, especially in those with diabetes, stomach or
intestine problems, a low-potassium diet, the elderly or those taking cardiac glycosides.

3 How to take

Always take Co-tenidone tablets exactly as your doctor has told you. If you are not sure, check with your doctor or
Swallow the tablets with water.
Usual doses:
• Adults: 1 tablet a day
• Children: Not recommended
If you are elderly or have impaired kidney function, your doctor may prescribe you a different dose.

If you take more than you should

If you have accidentally taken more than the prescribed dose, contact your nearest casualty department or tell your
doctor or pharmacist at once. Overdose causes an excessively slowed heart beat and low blood pressure with feeling
sick, difficulty breathing, weakness, dizziness, increased production of urine and changes in the levels of certain
chemicals in the body.

If you forget to take to take the tablets

If you forget to take a dose, take it as soon as you remember, unless it is nearly time for your next dose. Then go on
as before. Never double up on the next dose to make up for the one missed.

If you stop taking the tablets

Do not stop treatment early, especially if you have ischaemic heart disease. Talk to your doctor before you stop
taking the tablets and follow their advice.

4 Possible side effects
Like all medicines, Co-tenidone can cause side effects, although not everybody gets them.
Stop treatment and contact a doctor at once if you have the following symptoms of an allergic reaction
e.g. itchy skin rash, swelling of the face, lips, tongue or throat, or difficulty breathing or swallowing.
Tell your doctor if you notice any of the following side effects, they get worse or you notice any not listed:
Common (occurs in less than 1 in 10 users):
• slow heart beat
• cold extremities
• stomach and intestinal discomfort or pain, feeling sick
• tiredness
• gout
• increased levels of sugar in the blood
Uncommon (occurs in less than 1 in 100 users):
• sleep disturbances
• increase in liver enzymes (may cause itching and jaundice)
Rare (occurs in less than 1 in 1,000 users):
• your medicine may alter the numbers and types of your blood cells. If you notice increased bruising, nosebleeds,
sore throats or infections, you should tell your doctor who may want to give you a blood test
• nightmares, mood changes, seeing or sensing things that are not there
• confusion, dizziness, headache, visual disturbances
• worsening of heart failure, heart block symptoms causing fainting and irregular heart beat, low blood pressure on
standing causing dizziness and fainting
• worsening of intermittent claudication and Raynaud’s phenomenon, ‘pins and needles’
• difficulty breathing
• dry mouth/eyes
• yellowing of the skin or whites of the eyes (jaundice), inflammation of the pancreas or kidneys causing pain and
tenderness in the abdomen and back (pancreatitis or interstitial nephrititis)
• hair loss (alopecia), worsening of psoriasis, skin rashes
• changes in sex drive or potency
Other (frequency cannot be estimated from the data):
• constipation
• aching and tired muscles
• fits and coma (caused by low levels of sodium, magnesium and potassium in the blood)
• Lupus-like syndrome (a disease where the immune system produces antibodies that attacks mainly skin and joints)

Reporting of side effects
If you get any side effects, talk to your doctor, pharmacist or nurse. This includes any possible side effects not listed
in this leaflet. You can also report side effects directly via the Yellow Card Scheme at:
By reporting side effects you can help provide more information on the safety of this medicine.

5 How to store

Keep out of the reach and sight of children.
Store below 25°C in a dry place.
Protect from light.
Do not use after the expiry date stated on the label/carton/bottle. The expiry date refers to the last day of that
Ask your pharmacist how to dispose of medicines no longer required.

6 Further information

What Co-tenidone tablets contain

• The active substances (the ingredients that make the tablets work) are atenolol and chlortalidone. The 50/12.5mg
tablets contain 50mg atenolol and 12.5mg chlortalidone. The 100/25mg tablets contain 100mg atenolol and 25mg
• The other ingredients are macrogol, magnesium stearate, maize starch, polyvidone, sodium starch glycollate,
titanium dioxide (E171), Iron oxide red (E172), calcium hydrogen phosphate (E341), microcrystalline cellulose (E460)
and methylhydroxypropylcellulose (E464).

What Co-tenidone tablets look like and the contents of the pack
Co-tenidone tablets are brownish pink, circular, biconvex, film-coated tablets.
Pack size is 28.
Marketing Authorisation Holder and Manufacturer
Actavis, Barnstaple, EX32 8NS, UK.
This leaflet was last revised in September 2015

Actavis, Barnstaple, EX32 8NS, UK

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Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.