As Pennsylvania prepares for a 2018 launch of its medical marijuana program, conflicts between the state law and federal regulations has raised one more thorny issue: whether people using medical marijuana can buy a gun.

The short answer is: They can't.

Because federal law does not recognize individual states' medical marijuana programs, people enrolled in those programs are, from a federal perspective "an 'unlawful user of or addicted to any controlled substance'; and, therefore, prohibited by federal law from the purchase or acquisition, possession or control of a firearm," according to the Pennsylvania State Police.

In fact, the firearms transaction form that buyers are required to complete specifies that "the use or possession of marijuana remains unlawful under Federal law regardless of whether it has been legalized or decriminalized for medicinal or recreational purposes in the state where you reside."

Further, the state police have said, the federal prohibition also means that registered patients forfeit their ability to possess, apply for, or renew a state license to carry firearms and makes it "unlawful for you to keep possession of any firearms which you owned or had in your possession prior to obtaining a Medical Marijuana Card."

Andrew Sacks, a Philadelphia attorney who is heavily involved with medical marijuana law, called the rules a "hypocrisy," pointing out that there are no similar federal regulations precluding someone with a prescription for opioids from purchasing or owning a firearm.

While the issue may seem to only affect a small number of Pennsylvanians -- as of the last week of 2017 there were 10,000 Pennsylvanians registered with the state's medical marijuana program -- the state's gun ownership population is large.

Sacks said he has already been contacted by several people who have run afoul of the conflict between state and federal laws.

"This came to my attention because I got an email from a gun owner who had been denied [a firearms purchase] three or four weeks ago after enrolling in the medical marijuana program," he said, adding several other individuals have since contacted his law office as well. "So it is an ongoing issue."

The conflict between state and federal regulations as it regards medical marijuana programs is cropping up in other areas as well. When the state unveiled the program this year and invited companies to bid for licenses to operate in the state, one of the issues would-be business ran into was access to capital from banks, many of which did not want to become involved due to the federal restrictions.

Aside from commercial loans, the conflict between state and federal regulations also affected things as minor as companies opening business banking accounts with some banks.

"There is also a conflict when it comes to credit card companies, who often will not work with the marijuana industry for hear of federal penalties," said Morgan Fox, the director of communications with the Marijuana Policy Project in Washington D.C. "In addition, there are taxation issues ... which basically make it impossible for marijuana businesses to deduct operating expenses the way other businesses do."

Pennsylvania's program allows people with any one of 17 conditions to become eligible to use medical marijuana.

Reconciling the state medical marijuana programs and federal laws isn't an easy fix. It would require action by Congress, and there is little indication that will happen in the coming year, despite decisions by 29 states to legalize medical marijuana.

The good news for gun owners in Pennsylvania who are enrolled in the medical marijuana program is that while they won't be able to purchase new firearms, it is unlikely that the state will begin a program to confiscate existing firearms. The Pennsylvania State Police are not considering enacting a program requiring people to turn in existing firearms or ordering them to do so. Nor has this occurred in other states with similar programs, Fox said.

"As far as I know, there has never been a case of a medical marijuana patient being denied ownership of a firearm under this law or having federal law enforcement attempt to confiscate the firearms of patients," Fox said. "The few attempts to do this by state and local law enforcement have either been withdrawn after severe criticism or have lost in court."