The government is set to announce plans to streamline the process of requesting drugs through the NHS.
A new draft constitution is also set to be unveiled detailing the key goals and what the public are entitled to from the health service.
Under present measures, decisions on whether a patient is approved to take a drug are made by the National Institute of Health and Clinical Excellence (Nice) which has been accused of engaging in a "postcode lottery" or making decisions on drug provision based on the area patients come from.
Health secretary Alan Johnson said the new draft constitution would make it clear that patients are entitled to Nice drugs if they require the treatment.
He said: "What we have heard from patients is that one of their major concerns is the perceived 'postcode lottery' in access to drugs - that there are too many variations around who gets access to prescribed drugs and that these variations are a lottery depending on where you live.
"The draft constitution will address this by making it explicit that patients have the right to Nice-approved drugs if clinically appropriate," he added.
The head of the health department also said the national process for evaluating new drugs would be made more efficient and measures to ensure greater transparency in funding and drug provision issues would be introduced.
The NHS was launched in July 1948 under the Labour administration of Clement Attlee.