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" What is it used for?  High blood pressure (hypertension)  How does it work? This medicine contains two active ingredients, atenolol and chlortalidone (previously spelt chlorthalidone in the UK). Atenolol belongs to a group of medicines called beta-blockers, which block beta receptors in the heart, lungs and other organs of the body. Blocking these receptors prevents the action of two chemicals called noradrenaline and adrenaline that occur naturally in the body. These are often referred to as the &amp;#039;fight or flight&amp;#039; chemicals as they are responsible for the body&amp;#039;s reaction to stressful situations.Blocking the beta receptors in the heart causes the heart to beat more slowly and with less force. This reduces the pressure at which blood is pumped out of the heart to the rest of the body. This is just one of the ways in which beta blockers help to reduce blood pressure, however the whole mechanism is not fully understood. Chlortalidone is a type of medicine called a thiazide diuretic. Thiazide diuretics act in the kidney to remove water from the blood into the urine, by causing an increase in the removal of salts such as potassium and sodium from the blood. This removal of salts causes water to be drawn out of the blood and into the kidneys, where it is then excreted in the urine. Removing water from the blood decreases the volume of fluid circulating through the blood vessels. The drop in fluid volume results in a drop in the pressure of the fluid within the blood vessels, which helps to lower high blood pressure. It also decreases the effort required by the heart to pump blood around the body. The combination of these two medicines is particularly useful in treating high blood pressure. Warning!  This medicine may mask the symptoms of low blood sugar such as increased heart rate, tremor and nausea. People with diabetes should carefully monitor their blood sugar. This medicine may reduce your ability to drive or operate machinery safely. Do not drive or operate machinery until you know how this medicine affects you and you are sure it won&amp;#039;t affect your performance. It is recommended that blood tests are performed regularly to monitor the level of potassium in the blood. If this level is too low, potassium supplements may be required. If you experience any of the following symptoms while taking this medicine you should inform your doctor promptly, so that the amount of fluids and salts in your body can be checked: thirst, lethargy, confusion, weakness, drowsiness, muscle cramps, scanty production of urine, abnormal heart rhythm, seizures, nausea and vomiting. As diuretics cause your kidneys to produce more urine, you may prefer to take this medicine in the morning rather than before going to bed, as this will reduce the likelihood of you needing to get up in the night to visit the toilet. Seek further advice from your doctor or pharmacist. If you should require local or general anaesthesia, it is important that you inform your anaesthetist you are taking this medicine. Treatment with this medicine should not be stopped abruptly, particularly in people with inadequate flow of blood to the heart (ischaemic heart disease).  Use with caution in  Angina not well controlled by medical treatment (unstable angina) Asthma Chronic obstructive pulmonary disease (COPD) Diabetes Gout Heart failure History of allergies Hyperthyroidism Kidney disease Narrowing of arteries in the extremities (peripheral arterial disease) Psoriasis Thyrotoxicosis  Not to be used in  A problem common in the elderly, related to poor control of the working of the heart (sick sinus syndrome) Breastfeeding Defect of the heart&amp;#039;s electrical message pathways resulting in decreased function of the heart (heart block) Failure of the heart to maintain adequate circulation of blood (cardiogenic shock) Increased acid levels in the blood (metabolic acidosis) Known sensitivity or allergy to any ingredient Low blood pressure (hypotension) Pregnancy Severe narrowing of arteries in the extremities (peripheral arterial disease) Slow heart rate of less than 50 beats per minute (bradycardia) Uncontrolled heart failure Untreated tumour of the adrenal gland (phaeochromocytoma)  This medicine should not be used if you are allergic to one or any of its ingredients. Please inform your doctor or pharmacist if you have previously experienced such an allergy. If you feel you have experienced an allergic reaction, stop using this medicine and inform your doctor or pharmacist immediately. Pregnancy and Breastfeeding Certain medicines should not be used during pregnancy or breastfeeding. However, other medicines may be safely used in pregnancy or breastfeeding providing the benefits to the mother outweigh the risks to the unborn baby. Always inform your doctor if you are pregnant or planning a pregnancy, before using any medicine.  This medicine should not be used in pregnancy. Seek medical advice from your doctor. This medicine passes into breast milk. It is recommended that mothers should avoid using this medicine while breastfeeding. Seek medical advice from your doctor.   Label warnings  Do not stop taking this medication except on your doctor&amp;#039;s advice.  Side effects Medicines and their possible side effects can affect individual people in different ways. The following are some of the side effects that are known to be associated with this medicine. Because a side effect is stated here, it does not mean that all people using this medicine will experience that or any side effect.  Rash Slower than normal heart beat (bradycardia) Disturbed sleep Changes in mood Blood disorders Disturbances of the gut such as diarrhoea, constipation, nausea, vomiting or abdominal pain High blood glucose level (hyperglycaemia) High blood uric acid level (hyperuricaemia) which can cause kidney problems and gout Cold extremities, eg hands and feet Breathing difficulties due to a narrowing of the airways (bronchospasm) A drop in blood pressure that occurs when going from lying down to sitting or standing, which results in dizziness and lightheadedness (postural hypotension) Disturbances in the levels of chemical components (electrolytes) in the blood Deterioration of heart failure  The side effects listed above may not include all of the side effects reported by the drug&amp;#039;s manufacturer. For more information about any other possible risks associated with this medicine, please read the information provided with the medicine or consult your doctor or pharmacist. How can this medicine affect other medicines? When taken together with cisapride, sertindole, sotalol, astemizole, terfenadine or beta-agonist bronchodilators such as salbutamol, there may be an increased risk of abnormal heart rhythm, if low blood potassium (hypokalaemia) occurs with chlortalidone. If hypokalaemia does not occur, this risk is removed.  When taken together with other medicines which can cause hypokalaemia e.g. corticosteroids, carbenoxolone or beta-agonist bronchodilators such as salbutamol, there may be an increased risk of developing hypokalaemia. Potassium supplements may be required.When taken together with cardiac glycosides such as digoxin, there is an increased risk of adverse effects if low blood potassium (hypokalaemia) occurs with chlortalidone. There is also an increased risk of extremely slow heart rate when atenolol is taken with digoxin.Chlortalidone reduces the ability of the body to remove the medicine lithium. As this may give rise to adverse effects this medicine should not generally be taken with lithium.In diabetic patients, atenolol can prolong the lowering of blood sugar (hypoglycaemia) caused by insulin or other antidiabetic medicines. Individuals should monitor their blood sugar, as atenolol can also mask the signs of hypoglycaemia. Chlortalidone may increase blood sugar.When atenolol is taken together with calcium channel blockers such as verapamil, nifedipine or diltiazem, the risk of slow heart rate, hypotension and heart failure may be increased. Neither atenolol nor calcium channel blockers should be given intravenously within 48 hours of discontinuing the other.If atenolol is taken together with clonidine, there is a risk of a rebound increase in blood pressure if clonidine is stopped. The atenolol should be stopped several days before slowly stopping the clonidine.For further interactions of with the atenolol component of this medicine please refer to the atenolol monograph. Other medicines containing the same active ingredients   Co-tenidone Tenchlor Tenoret 50   Tenoretic Totaretic    Last updated 08.07.2004 "^^<http://www.w3.org/2001/XMLSchema#string>
<http://www.netdoctor.co.uk/medicines/heart-and-blood/a6249/atenixco-discontinued-in-the-uk/>