Oxazepam and diazepam (valium) are two very similar drugs. They are both benzodiazepines, and as kazzykat said they both increase levels of GABAa in the brain. However, the difference is in their half lives. Oxazepam has a much shorter elimination half life (basically how long it will stay in your system) than diazepam, being between 5 and 15 hours for oxazepam and up to 100 hours for diazepam. This is because when diazepam is metabolized (broken down) by your body, it converts into a number of metabolites (basically it gets converted into different substances in the body) which can hang around for a long time which can cause prolonged sluggishness and a 'hangover' effect. Also, as far as I know, oral oxazepam has a longer onset of action than oral diazepam (it takes longer to start working) so that is something you should bear in mind. However, ultimately oxazepam should act long enough for it to put you to sleep and for you to stay asleep, with potentially fewer side effects in the morning than diazepam. However, something you should bear in mind is that different drugs (even similar drugs within the same drug class like oxazepam and diazepam) can affect people in greatly different ways, one may knock you out and another may not do anything, so it is very individual. Finally, I would strongly urge you to speak to your pharmacist and doctor/prescriber, rather than asking TSR. because they will be able to give you up to date and accurate advice.