Side-Effects of Alkylamides
Alkylamides can be useful modulators of the CB2 receptor, they may be effective for treating some conditions. But how safe are they?
I am tempted to say "reasonably safe," but there is no answer that is short and also accurate. It does appear that they are fairly safe, but there are things we don't know.
Echinacea is the prime example of an alkylamide that has a long history of use. It seems to have a good safety profile, but some questions have been raised over the years. A review article in the journal Planta Medica concludes "Due to published long term studies with continuous ingestion of different Echinacea preparations up to 6 month with no reported toxicological concerns, Echinacea can be recommended also for long-term use." ([Review and Assessment of Medicinal Safety Data of Orally Used Echinacea Preparations.]) That article also dismissed the concerns that echinacea might make auto-immune conditions worse (such concerns were mostly theoretical, based on the idea that echinacea "strengthens the immune system." But we don't know with absolute certainty.
Aspirin was at one time part of a phenomenon much like the current CBD craze. In the 1920s, people were taking it for all kinds of reasons; aspirin was seen as panacea, a fountain of health. And yet we know that aspirin sometimes causes serious issues. After about 50 years of widespread use, it was discovered that children given aspirin sometimes develop Reyes syndrome, which can be serious, even life-threatening. Current guidelines are to never give aspirin to a child under 3, and never give aspirin to a child with chicken-pox or influenza-like symptoms. And adults who take aspirin face a risk of increased intestinal bleeding. It is not a common effect, but it does represent a real risk and some people experience problems from aspirin use. Or from the use of acetaminophen, ibuprofen, and other alternatives to aspirin.
There are no zero-risk options in this world. Some things are so dangerous that they should be avoided altogether, but other things fall into a continuum of risk. Moving around in a car has real risk; tens of thousands of people die from auto collisions each year in the United States. But people accept that risk, they see the potential benefits of autos as outweighing the risks.
One problem we face is that is impossible to prove that something is safe. Logically, it cannot be done. It is like trying to prove that a black swan does not exist. We can do ten tests that look for ten different ways that a treatment might be toxic and find no evidence of harm, but we have only looked at ten mechanisms. We can do another 20 different types of tests and find no evidence of harm. Does that 'prove' that it is safe? No.
Spilanthes has been used both as a medical herb and a food for a long period. That is a good sign. It is not proof of zero risk in all circumstances.