 Lorazepam is in a class of drugs called benzodiazepines that is used to treat seizures. Lorazepam has been widely used to treat children who have repeated or long seizures, a condition known as status epilepticus SE. However, lorazepam is not currently approved by the FDA for use in children under 18 years of age. Therefore, the purpose of this study is to gather the data needed for FDA approval. Specifically, we will 1 determine the best dose, and 2 evaluate its effectiveness and safety in stopping seizures. Part 1 is a pharmacokinetic study. These are studies designed to identify and describe one or more of the following basic pharmacological concepts in humans: absorption i.e. how much gets into the body; distribution i.e. where it goes in the body; and metabolism and elimination i.e. how the body gets rid of the medication and how long it takes. The study procedures involve taking blood samples from children, taking their vital signs, and conducting physical examinations. Informed consent will be obtained from all participants as required by federal guidelines. Patients will be divided into two groups. The first group will be patients who present to one of the 10 participating Emergency Rooms ERs in status epilepticus repeated or continuous seizures. We will either ask for consent in the ER, or if we know they have a seizure disorder and have frequent visits to the ER, consent them beforehand for future visits to the ER. The second group will include patients who have a known seizure disorder and agree to be electively admitted to the hospital for a dose of lorazepam when they are not having seizures. We will draw blood samples from patients for up to 48 hours and then follow up via telephone for 30 days from the day the medication was given to assess for side effects. 