Legal Question in DUI Law in California

First of all, don't drive if you are impaired by medication. If you are pulled over, don't answer questions! Drug DUIs can be easier to defend than alcohol DUIs because there's no fixed limit. But more to the point, you don't need the expense of hiring an attorney (and an expert toxicologist); and you don't want any other motorists or pedestrians to get hurt or killed.

Good tips. Also see http://www.avvo.com/legal-guides/ugc/drugs--dui-in-california-1.

You can be arrested and convicted of driving 'under the influence' of any substance, legal or illegal, prescribed or not, alcohol, drug, OTC, cough medicine, etc. There are no 'excuses' accepted, or defenses available just because you have 'need' of the drug. Don't drive impaired unless you want to go to jail.

The only other advice is to exercise the 5th Amendment right to SHUT UP and do NOT talk to anyone except an attorney about the case. Most police and prosecutors will happily tell you that 95% of people convict themselves by trying to be 'helpful and cooperative', either during initial contact, questioning, interview or interrogation.