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"Lawyer of the Year"

Harris County Criminal Lawyers Association (2014)

Houston Drug Lawyer

Houston Drug Lawyer John P. Keirnan - Over 40 Years of Experience

Houston drug lawyer

Are you or someone you know facing drug charges? Houston drug lawyers John P. Keirnan and Michael D. Mercer have successfully defended drug possession and distribution charges for over 40 years combined. Winning a drug case requires extensive knowledge of the law surrounding searches and seizures. Remember that police officers are not criminal defense lawyers and will often violate your constitutional rights when searching for drugs.

Our clients can rest assured that if their rights have been violated by a police officer, we will stop at nothing to make sure that evidence is thrown out. Call (713) 236-9700 today for a free 24/7 evaluation and speak with Mr. Keirnan and Mr. Mercer personally about potential defenses in your drug possession case. 




            Experienced Houston Drug Lawyer    

        (713) 236-9700


Houston Drug Attorneys Michael Mercer and Casey Keirnan have successfully defended the following types of drug possession cases:

  • Possession of a Controlled Substance

  • Possession of Marijuana

  • Possession of Marijuana wax or concentrated THC

  • Possession of a Dangerous Drug

  • Possession of Cocaine

  • Possession with intent to Deliver a Controlled Substance

  • Manufacture/Delivery of a Controlled Substance

  • Possession with Intent to Deliver Marijuana

Client Reviews

Have you been charged with possession of marijuana? The drug lawyers at Mercer & Keirnan Criminal Defense Attorneys have over 40 years of combined experience defending marijuana possession. "Marijuana" is defined as any Cannabis sativa plant, including marijuana seeds, preparation of the plant, or a package with traces of marijuana. There must be a "usable" amount of marijuana. Marijuana stems, therefore, are generally not sufficient for possession.


Call 713-236-9700 today to speak with Houston drug lawyers John "Casey" Keirnan and Michael Mercer about your drug possession case. You can also request a free quote online.

Possession of Controlled Substance Charges


Average Rating: 5 out of 5 (11 Reviews)


"Mr.Mercer is a great lawyer I will recommend him to anyone who needs a defense lawyer gets the job done and will fight for your freedom can't say anything bad about him I was facing 5 serious felonies and was able to get 4 years deferred probation Thank You again Mr. Mercer it was a blessing having you and your team fighting for my freedom"

by D.F. 3/20/2024


"Mr Mercer was a life saver! He came into our lives and helped tremendously with my case. I can’t say enough how much I’d recommend this man if you need legal assistance of any kind. He will work hard night and day to get the results you need! Don’t wait call now!"

by D.W. 2/24/2024

Looking for an experienced Houston drug lawyer for possession of controlled substance charges? The criminal defense lawyers at Mercer & Keirnan have over 40 years of combined experience defending possession of controlled substance charges in Houston. The Texas Controlled Substance Act lists 4 distinct penalty groups under which illegal drugs are classified. If you or someone you know has been charged with possession of a controlled substance, call Houston drug lawyer John P. Keirnan for a free evaluation.

Houston Drug Charge Defense Lawyer

Houston Drug Lawyer Defends Cocaine Possession

Section 481.115 of the Texas Health and Safety Code lists the penalties for possession and distribution of cocaine. Hiring an experienced Houston drug lawyer to defend your cocaine possession charge greatly increases your chances of getting the charge dismissed. Only an experienced drug defense attorney will know how to properly apply for alternative punishments like drug court, one alternative to jail time. Call a Houston drug lawyer at Mercer & Keirnan Criminal Defense Lawyers to defend your cocaine possession case today.


"I hired a top Houston drug lawyer with Mercer and Keirnan to defend my possession of a Controlled Substance Case. After a free consultation with Criminal defense attorney Michael Mercer, Mercer and Keirnan signed on to my case and after a few months my felony drug charge was dismissed!"

by RG One February 5, 2019


"I hired Mercer and Keirnan because of their experience handling DWIs and other charges.  Working closely with them throughout my case, it became very clear that I had made the right decision..."

by T. M. December 30, 2018

Prescription Drug Possession Lawyer

Looking for an experienced Houston drug lawyer to defend your prescription drug possession case? Texas takes prescription drug charges very seriously. It is an offense to possess a prescription drug without a valid prescription, or to deliver a validly issued prescription drug to another person. Penalties can be just as serious as those for controlled substance possession. Contact a prescription drug possession lawyer at Mercer and Keirnan Criminal Defense Attorneys for a free 24/7 consultation of your drug possession case. 


Experienced Houston Drug Possession Lawyer

Call (713) 236-9700 or Request a Free Quote Online

Do I Need a Lawyer for a Drug Case?

Many people facing a drug charge ask the question, "Do I need a lawyer for a drug case?" The answer is Yes. In many drug cases, there may not be enough evidence to prove the case. The arresting officer may have violated your constitutional rights in searching your person, your vehicle or your house, especially if the search was conducted without a warrant or without probable cause. The prosecuting attorney will go to great lengths to convince you that they have the evidence to obtain a guilty verdict. Without the knowledge and the reputation of an experienced Houston drug lawyer, the accused in a drug possession case stands little chance against the prosecutor.


Without an experienced Houston drug lawyer, the accused will not be taken seriously by either the judge or the prosecutor. A drug possession lawyer who is experienced in defending drug charges will know exactly what the prosecutor needs to prove their case against you and will expose the weaknesses of their case. With over 40 years of experience as Houston Drug Lawyers, John P. Keirnan and Michael D. Mercer will help you to achieve the best possible result in your drug possession case.

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