Anticholinergic plants

Vanderhoff, B.T. Mosser, K.H. Jimson weed toxicity management of anticholinergic plant ingestion. Am. Earn. Physician 1992, 46 (2), 526-530. 

Other plants of the nightshade family, including Atropa belladonna (deadly nightshade), Hyoscyamus niger (black henbane), and Datura stramonium (Jimson weed), contain atropine-like toxins that are anticholinergic, blocking the muscarinic receptors. An incidence in southern Utah of cattle poisoned on black henbane, with many death losses, was recently reported (Pfister, 2003). Atropine and atropine-like alkaloids are discussed Section 2.2.1.7. 

The base-catalysed racemization of the alkaloid (-)-hy oscy amine to ( )-hyoscyamine (atropine) is an example of enolate anion participation. Alkaloids are normally extracted from plants by using base, thus liberating the free alkaloid bases from salt combinations. (—)-Hyoscyamine is found in belladonna Atropa belladonna) and stramonium Datura stramonium) and is used medicinally as an anticholinergic. It competes with acetylcholine for the muscarinic site of the parasympathetic nervous system, thus preventing the passage of nerve impulses. However, with careless extraction using too much base the product isolated is atropine, which has only half the biological activity of (—)-hyoscyamine, since the enantiomer (+)-hyoscyamine is essentially inactive. 

Geriatric Considerations - Summary Alkaloids from the belladonna plant contain 3 potent anticholinergics and offer no advantage over other available drugs. Belladonna alkaloids possess potent anticholinergic effects and can cause dry mouth, blurred vision, delirium, confusion, psychosis, and increased risk of falls. This compound has no role in treating the older adult. 

A large number of prescription and nonprescription drugs, as well as a variety of plants and mushrooms, can inhibit the effects of acetylcholine at muscarinic receptors. Some drugs used for other purposes (eg, antihistamines) also have anticholinergic effects. Many of them have other potentially toxic actions. For example, antihistamines such as diphenhydramine can cause seizures tricyclic antidepressants, which have anticholinergic, quinidine-like, and a-blocking effects, can cause severe cardiovascular toxicity. 

The prototypical antimuscarinic anticholinergic drug is atropine (Fig. 19-2). Atropine is a naturally occurring substance that can be obtained from the extract of plants such as belladonna and jimsonweed. Other natural, semisynthetic, and synthetic antimuscarinic anticholinergic agents have been developed that are similar in structure or function to atropine. 

Note The best-known antimuscarinic or anticholinergic drugs are the belladonna alkaloids. The major drugs in this class are atropine, hyoscyamine, and scopolamine. A number of plants belonging to the potato family (Solanaceae) contain similar alkaloids. Atropa belladonna (deadly nightshade), Hyoscyamus niger (henbane), Datura stramonium (jimsonweed or thorn apple), and several species of Scopolia also contain belladonna alkaloids. 

Anticholinergic drugs can cause vivid and sometimes exotic hallucinations and this has led to their misuse. Plants containing atropine and related substances were used in witches brews in the Middle Ages to conjure up the devil, but even synthetic tertiary amines given in eye-drops and depot plasters containing atropine (SEDA-13, 114) have caused hallucinations. Postoperative confusion... 

The practitioner should be alert to the possible inoculation into the eye of any drug or substance with anticholinergic properties, including plants, cosmetics, perfumes, or medicines. Unilateral fixed and dilated pupils have been reported after the use of antiperspi-rants, transdermal scopolamine (Transderm Scop) for the prophylaxis of motion sickness, and from direct droplet contamination associated with the use of anticholinergic aerosols for treatment of acute asthma and other airflow obstructions. 

Tropane alkaloids, such as hyoscyamine and/or scopolamine, occur in the solanaceous plants Atropa belladonna, Datura stramonium, Hyoscyamus niger, and Mandragora officinarum. These alkaloids are powerful anticholinergic agents and can elicit peripheral symptoms (for example blurred vision, dry mouth) as well as central effects (for example drowsiness, delirium). They can potentiate the effects of anticholinergic medicaments. 

Anticholinergic hallucinogens include atropine and scopolamine, which are chemicals found in plants such as the deadly nightshade, mandrake, Jimson weed, and henbane. These drugs produce a semisleep state characterized by vivid visions and poor memory of the experience later. 

Atropine An anticholinergic hallucinogen found in certain plants (Chapter 12). 

The CBs used as pesticides are N-substituted esters of carbamic acid. CBs developed in the 1950s as insect repellents were found to have insecticidal activity, leading to the development of the napthyl CBs with high anti-ChE activity and selective toxicity against insects. One example is carbaryl it is widely used because of its low toxicity to mammals and its degradability. Aldicarb, a plant systemic, is more toxic than carbaryl. A few years ago aldicarb was associated with a July 4th holiday incident when West Coast residents complained of anticholinergic symptoms after eating aldicarb-contaminated watermelon. 

Common symptoms of exposure include mydriasis, sinus tachycardia, hypertension or hypotension, anxiety, hallucinations, psychoses, choreoathetosis, delirium, seizures, dry mouth, flushed skin, decreased gastrointestinal motility, ileus, urinary retention, and hyperpyrexia. Anticholinergic agents may be detected in the urine, but this does not direct clinical management. Due to multiple plant variations, the alkaloid content differs greatly. 

Anticholinergic poisoning occurs from belladonna alkaloids in various plants. Toxins may include atropine, hyoscyamine, and scopolamine. 

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