Propranolol helps patients diagnosed with some types of tumor, heart disease, high blood pressure, certain types of tremor, and abnormal heart rhythms. The effects of this medicine are based on dilating your blood vessels and improving the blood flow. Propranolol should be taken regularly, and if you are taking it for high blood pressure - for the rest of your life. This has to do with the fact high blood pressure cannot be cured - rather than kept under control. With the help of propranolol you will be able to keep your symptoms under control and avoid unpleasant and sometimes dangerous health effects. The following side effects are possible when propranolol is taken: tired feeling, nausea, constipation, vomiting, diarrhea, stomach cramps, sleep problems, and decreased sex drive. More serious side effect are possible, although rare, and need to be reported to your health care provider as soon as possible. The following ones are considered serious enough to be reported: headache with a severe blistering, uneven heartbeats, swelling of your ankles or feet, fainting, hallucinations, confusion, feeling light-headed, loss of appetite, clay-colored stools, depression, yellowing of the skin or eyes, or sore throat.