Propranolol (INN) is a sympatholytic nonselective beta blocker. It is used to treat high blood pressure, a number of heart dysrhythmias, those with thyrotoxicosis, and essential tremors. It is used to prevent migraine headaches, and further heart problems in those with angina or previous myocardial infarction. It comes in both oral and intravenous forms. It should not be used in those with an already slow heart rate and most of those with heart failure. Quickly stopping the medication in those with coronary artery disease may worsen symptoms. It may worsen the symptoms of asthma. Common side effects include: nausea, abdominal pain, and constipation. Greater care is recommended in those with liver or kidney problems. It may possibly cause harmful effects to the infant if taken during pregnancy. It was the first successful beta blocker developed. It is on the World Health Organization's List of Essential Medicines, a list of the most important medications needed in a basic health system. Propranolol is available in generic form; it is marketed in India under brand names such as Ciplar and Ciplar LA by Cipla, also other brands from AstraZeneca and Wyeth under brand names Inderal, Inderal LA, Avlocardyl, Deralin, Dociton, Inderalici, InnoPran XL, Sumial, Anaprilinum, and Bedranol SR (Sandoz).