An Arapahoe County District Court judge dealt a blow to prosecutors this week when he threw out all the charges against a medical-marijuana doctor.

Dr. Toribio Robert Mestas had been facing charges of forgery, attempt to influence a public servant, marijuana distribution and conspiracy to distribute marijuana. He was charged after writing what prosecutors said was a shoddy medical-marijuana recommendation to an undercover police officer.

But, in a lengthy ruling handed down Wednesday, District Court Judge Kurt Horton dismissed all the charges, saying Mestas’ conduct was protected under the state constitution. Horton also found that the U.S. Constitution’s protection of free speech applied to advice that doctors give their patients.

“Colorado’s Amendment 20 simply allows for a physician to certify that a patient might benefit from the use of marijuana as a medical treatment,” Horton wrote, “and it is then left up to the patient whether to apply for a medical marijuana registry card.”

The case is a setback for the Arapahoe County District Attorney’s Office, which has similarly charged at least one other medical-marijuana doctor after a series of undercover stings early last year. A spokesperson there said this morning she had no immediate comment on the ruling.

In Mestas’ case, an officer using the fictitious name “Joseph Butkus” visited Mestas’ office, which was linked to a dispensary, and asked for an exam so that he could receive a medical-marijuana recommendation. “Butkus” told Mestas that he suffered from daily back pain — the officer said he had “the body of an 80-year-old” — and sometimes had trouble sleeping. During his examination, Mestas noted that the undercover officer had high blood pressure, was overweight and looked 20 years older than he said he was.

Mestas wrote “Butkus” a recommendation to use marijuana to treat “severe pain,” and the undercover officer was then able to immediately go into the dispensary and buy marijuana. Prosecutors contended that the officer never told Mestas he suffered from “severe pain,” according to Horton’s ruling. But Mestas and another doctor testified that such a diagnosis was implied based on what the officer did say.

Horton agreed, finding that Mestas had performed the needed exams and given sufficient attention to the officer to make the recommendation.

“Dr. Mestas could have done more to support his Physician’s Certification,” Horton wrote. “However, the Court cannot find that Amendment 20 expressly required more.”

Horton also found that Mestas’ recommendation was separate from the sale of marijuana, thus negating the distribution charges.

“This is good for physicians in Colorado,” Mestas’ attorney, Matt Giacomini, said. “I think it recognizes …. the role of a physician.”

Arapahoe County prosecutors are still pursuing charges against another medical-marijuana doctor, Manuel Aquino, who is accused of writing shoddy recommendations to two undercover officers after brief exams. The case is currently scheduled for trial in August.

Mestas, meanwhile, continues to work as a doctor, occasionally writing medical-marijuana recommendations, Giacomini said. Mestas’ medical license is currently listed as active, with no disciplinary actions against it.

John Ingold: 303-954-1068 or jingold@denverpost.com.