Tenormin Precautions and Warnings (Cont.)

• Tenormin can interact with certain other medications (see Tenormin Drug Interactions).
   
• Tenormin may hide certain signs of hyperthyroidism. Do not stop taking Tenormin suddenly, as this can cause serious symptoms of hyperthyroidism to appear severely and without warning. Make sure to talk with your healthcare provider before stopping Tenormin so that it can be done in a safe manner.
   
• Tenormin may cause extreme low blood pressure and/or a slow heart rate in some people. Symptoms can include dizziness, lightheadedness, and fainting. If you develop any of these symptoms, contact your healthcare provider. Extreme low blood pressure is more likely to occur in people who are taking a diuretic, who are on dialysis, or who have diarrhea or vomiting.

Also, make sure not to drive, operate any heavy machinery, or perform any other tasks that require alertness before you know how Tenormin affects you.

• People with severe congestive heart failure who take Tenormin are at increased risk of worsening heart failure. Therefore, if you have congestive heart failure and your healthcare provider prescribes Tenormin, it is because he or she believes that the benefits of Tenormin outweigh the potential risks. He or she may choose to monitor your situation more closely.
   
• Using beta blockers, such as Tenormin, for a long period of time can lead to heart failure in some cases. If you notice any of the following symptoms, contact your healthcare provider: unexplained weight gain; swelling of the ankles, feet, or legs; cough; or shortness of breath (see Symptoms of Congestive Heart Failure for more signs and symptoms).
   
• People taking Tenormin should not abruptly stop taking it. In clinical studies, this has been shown to increase a person's chances of developing angina (chest pain), heart attack, or serious irregular heart rhythms (arrhythmias). This risk is even greater in people with existing heart disease.
   
• If you have kidney disease or kidney failure, your body may metabolize the Tenormin differently than intended. Therefore, your healthcare provider will monitor your situation more closely.
   
• Beta blockers, including Tenormin, should be used with caution (if even at all) in people with certain lung diseases, such as asthma, emphysema, chronic bronchitis, or chronic obstructive pulmonary disease (COPD). This is because beta blockers affect the lungs and can cause a narrowing of the airways. This risk is increased in people with certain lung diseases. If you develop problems breathing or wheezing while taking Tenormin, call your healthcare provider.
   
• For people with allergies, taking Tenormin may increase the reaction to the specific allergens, and your body may not respond to the usual doses of epinephrine.
   
• If you are going to have surgery, let your healthcare provider or dentist know that you are taking Tenormin.
   
• Tenormin is a pregnancy Category D medicine, meaning that it has clear health risks to an unborn child. Before taking Tenormin, let your healthcare provider know if you are pregnant or thinking of becoming pregnant. If you become pregnant while taking Tenormin, contact your healthcare provider immediately (see Atenolol in Pregnancy for more information).
   
• Tenormin is known to pass through breast milk. Therefore, if you are nursing and taking Tenormin, it is generally recommended that you stop nursing. Talk with your healthcare provider about your particular situation.