Are There Established Therapeutic Levels for Prescription Medication?

Interviewer: Is there a therapeutic level that police test for when they test your blood or a threshold for these medications?

Brian: There are therapeutic levels, scientifically declared therapeutic levels. However, the problem is especially when we’re talking about count two, when someone is driving with medication in their system and they are taking it as prescribed.

When we have printed therapeutic levels, whether someone is inside those therapeutic levels or outside of those therapeutic levels that doesn’t necessarily speak to whether someone is taking the medication as prescribed. They are really two different things.

The law does not say that it is legal to drive within therapeutic levels. The law does not say that is a defense to count two DUI, if someone is driving on prescription medications and the prescription medication are being taken within therapeutic levels.

The law says that it is a defense if a person is taking prescription medications and they are taking those medications as prescribed. Therapeutic levels don’t really speak to that.

Therapeutic Levels Cannot Be Used in a Defense  

For example, someone who has been taking medications for years tend to have a build-up of those prescription medications and as time goes on, there is a lessening effect that those prescription medications have on them, so they need to take higher dosages.

If the person has been on the medication for a long time they may show that outside of normal therapeutic levels but they are literally taking the medication as prescribed.

The prosecutor can talk about therapeutic levels, the defense can talk about therapeutic levels, and in reality it has nothing to do with whether the person has taken their medication as prescribed.

There Are State and Federal Lists of Illegal Drugs That Are Considered to Not Affect Driving Ability

Interviewer: Is there a list of common medications that are considered to have no affect on driving or to have an effect on driving?

Brian: There are several lists, one at the state level and one at the federal level, of chemical substances that are considered illegal to use.

Interviewer: They designate between legal and illegal but they don’t designate between having an effect on driving or not having an effect, right?

Brian: Yes, that is correct.

Interviewer: Impair ability, or an impair ability factor, do they assign that to these chemicals?

Brian: They don’t. It’s not like DUI alcohol where they can say if you are above a 0.08 then it is against the law. There is nothing that says that if you are outside a therapeutic level it is against the law. It is simply did it cause impairment or was it present and you were not taking it as prescribed.

The problem with this whole idea is were you taking the medication as prescribed and was it prescribed to you? The problem is the only person who can really testify to that is the person taking the medications.

Can Your Testimony About Your prescription Medication History Help You at Trial?

Unless, for some reason, there is some sort of assistant that is helping the person in taking their prescribed medications. If the only person that can testify to that is the person who is taking the prescribed medications and that person is also the defendant.

Now all of the sudden you get into constitutional issue because the person has a right to remain silent but they are allowed to testify. Do they want to testify? Do they want to evoke their right to remain silent? Should they be punished simply because they evoke their right to remain silent?

There is no one else to testify to whether they are taking the prescription medications as prescribed. Doctors can’t really explain that. You can put on scientists who can say the person was or was not within therapeutic levels.

Again, that doesn’t speak to whether or not the person was taking prescription medications as prescribed. They are the only ones who can testify to that. So in a way it becomes a Catch 22.

By Brian Douglas Sloan

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Why Attorney Brian Douglas Sloan?
Phoenix DUI Lawyer

Why Attorney Brian Douglas Sloan?


18+ Years SOLELY Focused on DUI Defense


4,100+ DUIs Successfully Defended

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“I am one of only a handful of Phoenix DUI Lawyers that focuses solely on DUI Defense representation.”

I have spent my entire career focused on DUI Defense representation, having personally defended more than 4,100+ DUI clients in the past 18+ years.

If you’re looking for a divorce attorney, tax attorney, or civil attorney, then I can comfortably say: "I’m not the one for you".

Coming up with traditional, as well as outside-the-box motions and defenses for my clients, often with good results, is the hallmark of my practice.

Lawyers that say they are "aggressive", or "will fight for you", are a dime a dozen. They use these phrases because that is what they think people want to hear. The truth of the matter is, being "aggressive" rarely gets the client anywhere in these court systems. Being "aggressive" isn’t the same as being good, and is often used to put on a show for a client to hide the fact that they aren’t doing anything meaningful for the client.

The same is true for the lawyers that claim to do DUI Defense... and Criminal Cases..., and Accident cases..., and Divorces. A Jack-of-all-Trades is a master of none. By handling all different sorts of cases, they take away from their ability to truly focus on DUIs, and keep up to date on the latest changes in DUI Defense Representation.

What I offer is intelligent, quality DUI Defense, at an exceptional price.

I am one of only a handful of Arizona DUI Lawyers that focuses solely on DUI Defense representation.

I have not only taught other lawyers how to do DUI Defense Representation at statewide seminars, but I produce DUI Legal Guides used by defense lawyers across Arizona.

I am one of the most award-winning DUI Defense Lawyers in Arizona; have been recognized nationally, including in a 2022 issue of USA Today; and there are only a few lawyers in Arizona who have personally defended more DUI cases than I have. I am also one of the most reasonably-priced DUI Lawyers, as I pride myself on charging a Flat Rate only for the legal services you need, and not for the legal services you don’t.

I am also the lawyer who people call once they realize that their original lawyer screwed something up, gave them false hope or false promises, or simply just took their money and didn’t do much on the case. You would be surprised at how often this happens.

Save yourself the trouble of hiring the wrong lawyer, and hire the right DUI Defense Lawyer from the start.

You can reach me on my personal cell phone: 480-720-7839.

Let me know if you have any questions!

Brian Douglas Sloan

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