Heart failure is a condition in which the heart that is not pumping effectively. According to the University of Maryland Medical Center, heart failure may develop suddenly or gradually over a number of years. Coreg CR, generic name carvedilol, is an extended-release beta-blocker medication used to treat mild to severe heart failure and high blood pressure. It relaxes the blood vessels and slows heart rate, allowing the heart to work more efficiently. However, there are some dangers associated with taking Coreg CR.
Severe Allergic Reactions
Although most people tolerate Coreg CR well, there have been serious allergic reactions reported with its use. Signs of a serious allergic reaction, called anaphylaxis, include itching, hives, wheezing, shortness of breath, and difficulty swallowing due to swelling of the mouth, lips and tongue. According to PubMed, these symptoms indicate a medical emergency and should be reported to a doctor immediately.
Effects on Blood Sugar Levels
People with diabetes may not be able to take Coreg CR. It can also affect the blood sugar levels of people without diabetes. According to PDRHealth, this drug can mask the symptoms of low blood sugar and can also create high blood sugar levels, called hyperglycemia. The signs of hyperglycemia include increased hunger, thirst and urination, as well as weakness and blurred vision. These symptoms should be reported to your physician at once.
Cardiovascular Effects
In some cases, Coreg CR can act to worsen the heart condition. According to eMedTV, it can worsen angina, cause an irregular heartbeat, and even worsen heart failure. The signs of worsening heart failure include unexplained swelling and weight gain, along with shortness of breath. Coreg CR may also increase cholesterol and triglyceride levels; and cause or worsen peripheral vascular disease. Symptoms of PVD include cold feet, numbness in the feet at rest and calf pain on walking that disappears with rest. Coreg CR can also cause periods of extremely low blood pressure that can cause fainting and dizziness.
Liver Problems
Those with liver disease may not be able to take Coreg CR. According to eMedTV, Coreg CR can increase the levels of liver enzymes. Those who are on Coreg CR will need to have their liver enzymes checked periodically by their doctor.
Other Dangerous Effects
Coreg CR can mask the signs of hyperthyroidism, particularly a rapid heartbeat. It can worsen allergic reactions, because medications such as epinephrine may not work as effectively. This drug can worsen shortness of breath in people with asthma. Coreg CR can also interfere with other medications, including clonidine, paroxetine, cyclosporine and digoxin. Coreg CR should never be stopped suddenly as withdrawal symptoms, including chest pain and shortness of breath, can occur.
