What started out as a pleasant cup of orange pekoe, turned into a hellish kind of high tea, when two elderly women were rushed to hospital after eating cookies baked with cannabis oil.

Gloria, 88, was staying at her daughter’s house when she invited her sister over for a visit. But what’s a spot of tea without biscuits? In search of something sweet, Gloria rummaged through the freezer until she found some baking.

Within the hour, the women thought they were dying. Hearts racing, mouths dry as desert air, they were dizzy and disoriented. When they began hallucinating, they needed help, fast.

Gloria called 911. Wheeled into the ER, the sisters were placed in an examining room while the paramedic, a knowing look in her eye, explained to the attending physician the ladies had become symptomatic after tea and cookies.

The baker confirmed suspicions, and supportive care was started, including IV fluids, mild sedation and monitoring.

“An hour later, once they knew they weren’t dying, the ladies were laughing their heads off,” the ER doctor said.

While cannabis use is increasing in the silver-haired set, side effects can be anything but funny. Few studies have been done, making dancing with Mary Jane wrought with stumbles.

According to National Post medical reporter Sharon Kirkey, Canadian family doctors have been advised there are only four conditions for which cannabis has been proven to offer benefit: nerve pain, palliative and end-of-life pain, chemotherapy induced nausea and vomiting, and spasticity due to multiple sclerosis or spinal cord injury.

Marijuana may also help with PTSD, chronic pain, insomnia and anxiety in some individuals. A study published last year in the European Journal of Internal Medicine followed 3,000 older patients and concluded cannabis led to a decrease in pharmaceuticals, including opioids. While this is encouraging, the negatives of cannabis use in seniors can be serious.

Marijuana has been linked to psychosis and schizophrenia in some individuals (mostly when they are young), but the elderly should beware.

Cannabis may also be linked to bipolar disorder and depression. Memory loss and hallucinations associated with its use can confuse diagnoses for people with dementia. Marijuana relieves anxiety for some patients; for others it has the opposite effect.

Already at risk for falling, getting around could be catastrophic for stoned seniors.

Those with lung problems should never smoke the stuff – and while we’re at it, those who struggle with maintaining a healthy weight might want to stay away. Infamous post-pot snack attacks can lead to over eating and weight gain.

According to The Beat (ottawa.ca), a site devoted to the latest in heart and cardiovascular care and research, when you use marijuana, your heart rate and blood pressure increase, forcing your heart to work harder. If you smoke marijuana, the capacity of your blood to transport oxygen to your heart is reduced.

Ingesting oils is often recommended as a safe way for seniors to protect their lungs and to regulate dose.

Oils aren’t absorbed as quickly, which sounds good in theory because you don’t get as high as fast. The problem is, when people don’t get immediate effect, some people may take more.

Like the sisters discovered, one minute you’re fine, and then shazam! You’re off on a magic carpet ride that can last anywhere from hours to days.

While marijuana was legalized almost a year ago, the federal government won’t give edibles—things like pot-butter baked brownies and laced lollipops—the greenlight until later this year. That might be good, according to health-care professionals who’ve seen the horrific side effects of overindulgence.

At issue is the level of tetrahydrocannabinol (THC), the ingredient that makes you high. Antidepressants, heartburn medications and some antibiotics, as well as high-blood pressure meds, can be affected by THC, decreasing the pharmaceuticals’ effectiveness. On the other hand, cannabinoid (CBD) which doesn’t get you high, can slow the metabolism of some drugs, increasing their potency.

It can be hard to get the straight dope, but with legality in place, the doors have opened for further studies, which should help to establish safer guidelines. For now, Canadians are tiptoeing (or in some cases, dizzily dancing) along largely new terrain as medicinal and recreational cannabis use becomes more popular.

As with all drugs, it is best to consult your doctor. Cannabis can help with an array of ailments, but everyone reacts differently. The grass isn’t always greener, especially for seniors.

Shannon Linden writes magazine and newspaper articles, kids’ books, and grocery lists. See shannonlinden.ca