To start, for full disclosure -- I am no expert on medical marijuana use, and I do not prescribe marijuana. This is simply my perspective as a cardiologist.
I have smoked marijuana once in my life, and that was while in medical school. I choose not to smoke marijuana, simply because I have no interest. However, I believe people should have the right to choose to purchase and smoke marijuana if they so desire.
I see a lot of patients who admit that they use marijuana. There are probably many more who use it and don't disclose to me or their other medical medical providers.
There are reasonable medical uses for medical marijuana. Nausea caused by chemotherapy, poor appetite and weight loss due to chronic illnesses, and muscle spasms from multiple sclerosis are among recommended uses for marijuana.
Often I see patients who are using marijuana to "treat" various aches and pains that in many cases they have never sought care for from a physician in the first place. I see patients who use marijuana to treat their anxiety and stress, or self-treat other psychiatric illnesses.
There are some possible harms from chronic marijuana use, whether for recreational or medicinal purpose. Like any substance, or any medication, there are side effects.
First, of course are the "munchies". Most of my patients are overweight or obese. The side effect of hunger from smoking marijuana does not help people make good food choices to facilitate their health.
Marijuana is not benign when it comes to the heart, either. There isn't much research, because marijuana was illegal for so long, so we have no information about what it does to the blood vessels, or even the brain for that matter. However, it is known to lead to high heart rate and fluctuations in blood pressure. And, some emerging research suggests that marijuana increases the risk of a heart attack.
If you smoke marijuana regularly, whether for recreational or medicinal purposes, it's probably a good idea to discuss with your physician.