Aconitum napellus (Monkshood): A beauty with poison

Photo: Acontium napellus

All we want is beauty in everything. It's a human nature. But everyone will also conform that everything that is beautiful always doesn't come with bless. It may turn into the cause of our sufferings. 

Acontium napellus (Monkshood also known as wolf's bane) is such a plant that is very attractive when you look. Even you may be convince to keep in your room as a ornamental plant. But along with it's impressive look it is poisonous too. Let's have a short account on "A beauty with poison".

Aconitum napellus is a perennial herb often grown as an ornamental plant due to its attractive blue to dark purple flowers. All parts of the plant, especially the roots, contain toxins. Aconitine is the most dangerous of these toxins. It is most noted as a heart poison but is also a potent nerve poison. Raw aconite plants are very poisonous.They are used as herbs only after processing by boiling or steaming to reduce their toxicity.

A. napellus has been used since ancient times as a poison used on spears and arrows for hunting and battle. As wolfsbane, it was believed to repel werewolves (and real wolves!). Ancient Romans used it as a method of execution.

A. napellus is native to western and central Europe where it is considered one of the most poisonous plants. Aconitine poisoning is rare in North America. When it does occur, it is generally due to confusion with an edible plant or unintentional ingestion by children. However, with the increasing popularity and availability of herbal medicines containing A. napellus, aconitine poisoning could occur more frequently.

Aconitine poisoning is most common in Asia due to the widespread use of herbal medications. In Hong Kong, aconitine is responsible for the majority of serious poisonings from Chinese herbal preparations. While the source of aconitine, especially in China, is usually Aconitum carmichaeli (chuanwu) or Aconitum kuznezoffii (caowu), the toxicity is similar to A. napellus.

Alleged therapeutic uses of A. napellus include treatment of joint and muscle pain. As a tincture applied to the skin, it is claimed to slow the heart rate in cardiac patients. Other claimed uses include reduction of fevers and cold symptoms.

In poisonings, the onset of symptoms occurs within minutes to a few hours after swallowing. The severity of aconitine poisoning is related to the rapid onset of life-threatening heart rhythm changes. Other symptoms can include numbness and tingling, slow or fast heart rate, and gastrointestinal manifestations such as nausea, vomiting, abdominal pain, and diarrhea. Respiratory paralysis and heart rhythm abnormalities can lead to death. The treatment is symptomatic and supportive; there is no specific antidote.

There is a very low margin of safety between therapeutic and toxic doses of aconitine. For example, a 66-year-old woman with no known heart disease obtained some from an herbalist. She was instructed to make a tea with it to treat her osteoarthritis. About 90 minutes after drinking the tea she developed numbness of her face, arms, and legs. This was rapidly followed by nausea, weakness, and chest pressure. In an ER, she was found to have an abnormal heart rhythm. After 4 hours of treatment with drugs and electrical shocks to her heart, a normal heart rhythm was restored.

There are cases of poisoning in which people intentionally swallow A. napellus they grow for themselves because of its claimed therapeutic effects. A 21-year-old man acquired Aconitum napellus plants after reading a book on herbal medicine. He ground up the roots of the plants and filled capsules with the dried material. He then took 1 capsule daily for several months to treat his anxiety. In order to increase the effects one evening, he swallowed 3 capsules and went to sleep. Five hours later he awoke with generalized numbness, nausea, diarrhea, dizziness, chest pain, shortness of breath, and defective color vision (he was seeing purple). It was believed that early symptoms went unnoticed because he was asleep. In an ER, his heart rate was very slow at 43 beats per minute, and he had an abnormal heart rhythm. Plasma concentrations of aconitine supported poisoning by A. napellus. He spent 48 days in the hospital.

Acknowledgment: Poison Control