In any case where police can show that the blood is relevant evidence then blood, like any other evidence, may be drawn without a court order. If you cause an accident while under the influence, are suspected of using illegal substances while on probation/parole, or cause an injury to a person while under the influence of a controlled substance your blood instantly becomes evidence.

A police officer can, and will, take you to a hospital where the medical staff will strap you down if necessary while blood is drawn. Because of the fact that the drugs will leave your blood stream in a short period of time, and assuming they are evidence, the blood may be withdrawn immediately without court order. State laws vary on what circumstances will allow for this practice, but most allow for forced blood draw for simple DUI.

I have personally arrested dozens of persons for driving under the influence or causing an accident while driving under the influence. About 20% of the time people refuse to give a sample in an important case(ie injury caused during DUI accident) and I personally took them to the hospital for a forced blood draw. One of our two local hospitals refuses to do it unless there is injury to a party for ethical reasons.

Ask yourself this question; If your family was killed by a driver under the influence of drugs only, prescribed or not, do you want that dirt bag to walk free because the police can't draw the blood they need for evidence??? North Korea, no. This is the U.S. where we must weigh the rights' of the thousands of innocent people that are injured/killed by DUI every year against the rights' of someone who is stupid enough to say "DUI is bad, but it's ok for me to do it!"

Here is an excerpt from Michigan story:

"After police stopped Robert H. Miller for driving erratically here one afternoon in February 2001, they asked for his license and registration. Then they asked for something else: his blood. Having been convicted of drunk driving once before, Mr. Miller refused to cooperate. So after he was taken to a hospital, five officers pinned him to the floor as a medical technician stuck a needle in his arm. His blood-alcohol level was 0.266% -- more than twice the legal limit. Mr. Miller, who declined to comment, challenged the tactic in court but lost. He pleaded no contest, was sentenced to up to 90 days in jail and lost his license for 18 months." web page