The legalization of medicinal marijuana has led to more widespread use for pain relief and other issues, but not all doctors are sold on it.

While Michigan is one of 33 states to legalize medical marijuana and is one of eight to regulate marijuana for medicinal and recreational uses for adults, very few clinical studies have been conducted on overall effects on health, according to the Michigan State Medical Society, which is advocating for more research.

“We still lack a lot of research on the use of (marijuana)” and the active ingredient THC (tetrahydrocannabinol) and CBD (cannabidiol),” said Mohammed Arsiwala, M.D., president of the medical society. “The use of (marijuana) CBD (oils and in edibles) has come into a lot of favor with individuals with chronic pain. We have significant concerns with adolescents and pregnant women because of other risk factors.”

Arsiwala said doctors believe there needs to be more discussion on the health effects of marijuana and the differences between hemp-based CBD oils and edibles and marijuana-based CBD products that contain high or uncertain levels of THC.

“We should be talking and researching the long-term health effects. We haven’t done that yet,” he said.

Joel Kahn, M.D., a cardiologist in Bingham Farms at the Kahn Center for Cardiac Longevity, said there is widespread confusion about the effects of hemp CBD products and marijuana CBD products.

Hemp-based CBD oils and similar products hit the market in Michigan about the same time the state approved recreational use in 2018. The U.S. government approved hemp use in December as part of the federal farm bill. Hemp-based CBD oil products can be purchased at most grocery stores, pharmacies and some gas stations, Kahn said.

“Further study is needed (on marijuana-based products). There can be an increase in heart rate from using CBD products containing THC,” Kahn said. “Users should be concerned about the quality of the products they are using, but shouldn’t be concerned if it is hemp.”

Both hemp and marijuana are derived from the cannabis sativa plant. Hemp is the female plant and has no THC, or just trace amounts. Marijuana is the male plant that has seeds and flowers and can contain as much as a 30 percent concentration of THC. Another difference is hemp is legal under federal law and marijuana is still illegal.

Kahn said people shouldn’t confuse buying hemp CBD products at health food stores and buying CBD products at a regulated marijuana store or online.

“I am unconcerned about hemp oil and effects on the heart,” Kahn said. “It can be used for pain, sleep, stress and anxiety.”

But purchasing CBD oil in a medical marijuana clinic can pose risks for a variety of people with medical conditions, doctors said.

“If you walk into a medical marijuana clinic and buy (marijuana-based) CBD oil, you can also buy a range of THC mixture, low, medium or high, based on your recreational desire,” Kahn said.

Kahn said he doesn’t recommend people with heart conditions use marijuana in any form.

“Someone with a fragile cardiac status I would caution them to avoid (marijuana) because of the THC,” Kahn said. “Maybe try hemp-based products for sleep, anxiety, and buy lowest THC concentration.”

Daniel Clauw, M.D., an anesthesiologist and director of the Chronic Pain and Fatigue Research Center at Michigan Medicine in Ann Arbor, said there are good and bad side effects to using marijuana for treating aches, pain and seizures. Each patient should understand the effects on their bodies, he said.

“There are a lot of things to use to treat aches and pains without using drugs,” said Clauw, adding that exercise, better sleep and reducing stress can help. “As you move into medications to treat pain, we don’t know where cannabis lies” from a research standpoint.

However, Clauw said, many emerging studies are showing that CBD alone can be effective in treating pain. CBD alone has no side effects, no psychoactive or addictive aspects, he said.

“A lot of people are using high-THC cannabis to treat pain. They should be using CBD alone. Or if they prefer, high CBD, low THC marijuana products,” Clauw said.

Since marijuana has been legalized, Clauw said, one of the problems is that salespeople at dispensaries do not have medical pain management training. “They are selling high-THC strains,” he said. “When (patients) use high THC levels for pain, they are overshooting the dose, and it is not what they should be using for analgesic pain.”

Andy King, M.D., an emergency medicine physician at Detroit Medical Center and assistant professor of emergency medicine at Wayne State University medical school, said hospitals in Colorado and in Michigan, including DMC, have been reporting a growing number of people who are coming into ERs with marijuana poisoning and overdose symptoms.

King, who also is medical toxicology fellowship director at DMC, said ER doctors are also starting to see a significant increase in children and adolescents coming in with various marijuana-related medical problems.

“Most of the time if an adult gets too much, they are OK, but if children come in they usually have a higher (marijuana) dose and sometimes have to be put on a ventilator” for breathing assistance, King said. “There is no good antidote.”

Arsiwala said a large concern of physicians is the growing number of edible marijuana products being used by pregnant women and adolescents, especially children with still developing brains.

While Clauw also said edibles are preferred by patients for treating pain, emergency room doctors are seeing a big spike in overdoses because people don’t understand the dosages are high.

“Some edibles are incredibly potent. You take a little gummy bear and you are super-high for 24 hours … paranoid,” he said. “Kids are doing it.”

King said he has seen people report to the ER with cannabis-induced tachycardia, dangerously rapid heart rates, a situation that can be fatal.

Edible marijuana products also are causing problems, King said. More than half of calls made to the Michigan Poison Center at Wayne State University concerning marijuana exposure through edibles like brownies, chocolate bars, candy and gummies involved children as young as 6 years old.

Since the beginning of the year, the Michigan Poison Center at WSU has received 420 calls related to marijuana exposure, 104 of them involving children under 18 years old. In 2014, the poison center received one call for pediatric exposure to edible pot. By 2018, the number had risen to 46 and so far this year through August, there have been 59 reports.

Younger children, 2 or 3 years old, can become unresponsive and may stop breathing, requiring a breathing tube and ventilator.

“A typical marijuana cigarette holds about 10 mg of THC,” King said. “That’s what you see in a gummy bear. That’s a dose for a novice person to take to get the psychedelic or enjoyable effects of THC. These edibles can go up to 10 times that amount.”

Michigan is second only to California in the number of registered medical marijuana patients, according to Kaiser Health. Since 2008, Michigan has allowed the sale of THC-containing products to people who have obtained a prescription from a physician for specific diagnoses, primarily chronic pain.

In 2012, Colorado and Washington became the first states in the nation to legalize marijuana for recreational use. Colorado has accumulated more than $1 billion in tax revenues generated since legalization.

Michigan is now rated as the second-largest medical marijuana market with 283,770 patients. The Michigan House Fiscal Agency has estimated that marijuana sales will near $949 million in 2020, bringing in about $100 million from the 10 percent excise tax and 6 percent sales tax.

But danger signs are on the horizon, Michigan doctors say.

King and Arsiwala said more research is needed on how pot affects the organs of adults and children.

“We know about alcohol, cocaine and opioids. We don’t have the same data for marijuana,” Arsiwala said. “We know smoking cigarettes for a long time causes cancer, COPD, lung disease, stroke, heart disease. We think it is the same for smoking pot, but we can’t say with confidence.”

King said ER doctors at DMC and Wayne State plan to conduct more studies on marijuana.

“There is one syndrome that is being studied now: cannabinoid hyperemesis syndrome. We see this a lot more in the ER,” King said.

CHS is a condition that leads to repeated and severe bouts of abdominal pain and vomiting.

“(Patients entering ERs with these symptoms) are heavy users of marijuana,” King said. “There is no blood test for it. We are pretty sure it is tied to pot use, but it is hard to convince them to stop.” Sometimes patients are hospitalized because of the pain and the need to conduct tests to rule out other problems, he said.

King said one of the biggest surprises he has concluded about patients coming in for marijuana-related issues is misconceptions people have about pot.

“People aren’t aware of the downsides of marijuana use like they know the risks of smoking cigarettes or using (methamphetamine) or opioids,” he said. “Some use it recreationally. You can get inebriated. They think when you smoke pot you just drive slower, but it decreases reaction times. You are more prone to accidents.”

Long-term pot use could affect the lungs like tobacco smoking does. “We can’t yet say one way or another,” King said. “Smoking unfiltered pot can allow more tar into the lungs, more carbon monoxide than other cigarettes, more particulates. You might see more chronic bronchitis or COPD.”

Arsiwala agreed. “We don’t know what we don’t know,” he said. “This is why more people need to stop and think about what they are putting into their bodies.”

Jay Greene: (313) 446-0325 Twitter: @jaybgreene