Original Link
https://zhuanlan.zhihu.com/p/74654442
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Before we begin, let’s start with a simple question: Is 654-2 scopolamine (東莨菪鹼) or anisodamine (山莨菪鹼)?
Since it is not commonly used, I often confused the two. Later, I came up with a mnemonic trick, and since then I never got confused again. Let me share it with you:
6542, shouldn’t it be 65432 in sequence? Where is 3?
It turns out it “ran into” the Chinese characters, that is 3 (shan, 山) … anisodamine (山莨菪鹼).
The above is entirely fictional, just to help memorization.
In fact, 654-2 is just the usual name of the drug, its generic name is racemic anisodamine (消旋山莨菪碱), available as tablets and injections.
1. The Origin of the Name 654-2
Why was racemic anisodamine named with such a pure number?
There is a historical reason:
Anisodamine was the first alkaloid extracted from the Solanaceae plant anisodus in China, and this achievement was completed in April 1965, hence the code 654.
Anisodus tanguticus (山莨菪), belonging to the Solanaceae family anisodus genus, is an endemic plant in China, also known as Zhangliu (樟柳), Tangchuan Nabao (唐川那保), Tanggutelangdang (唐古特莨菪) and others. It is mainly distributed in mainland China in Gansu, Tibet, Yunnan, Qinghai, and other areas.
The natural product is called “654-1,” which is the right-handed isomer; the artificially synthesized product is called “654-2,” which is the racemic form. The mechanisms of action between the two have no difference; only the latter has higher efficacy. Currently, the “654-2” is widely used clinically.
Simply put, 654-2 is an anti-M cholinergic drug, mainly used to relieve smooth muscle spasms, gastrointestinal colic, biliary spasm, acute microcirculation disorders, and organophosphorus poisoning.
2. Differences between 654-2 and Atropine
Atropine is an alkaloid extracted from belladonna and other Solanaceae plants; it is an anticholinergic drug that blocks M cholinergic receptors. Its main indications include:
Relieving smooth muscle spasms (including relieving vasospasms and improving microvascular circulation);
Inhibiting gland secretion;
Relieving vagal nerve inhibition of the heart, thus increasing heart rate;
Dilating pupils, increasing intraocular pressure;
Stimulating the respiratory center.
1. Similarities between 654-2 and atropine:
Both have peripheral M cholinergic receptor antagonistic effects and can relieve smooth muscle spasms caused by acetylcholine. They relax gastrointestinal smooth muscle and inhibit peristalsis, with effects slightly weaker than atropine. They can also relieve microvascular spasms and improve microcirculation.
2. Differences between 654-2 and atropine:
654-2 has weaker inhibition of salivary gland secretion and mydriasis, about 1/20 to 1/10 that of atropine.
Since it poorly crosses the blood–cerebrospinal fluid barrier, its central effects are also weaker than atropine, rarely causing central nervous system excitation symptoms.
3. Differences between “Anisodamine” and “Scopolamine (東莨菪鹼)”
At the beginning, it was mentioned that anisodamine and scopolamine (東莨菪鹼) are easily confused because their names differ by only one character, and both are “M-type cholinergic receptor blockers,” both used in treating smooth muscle spasms of the digestive system.
However, in fact, the differences between them are quite significant, and their clinical applications also differ considerably. Therefore, we must strictly distinguish between the two and not confuse them.
The following table summarizes the main differences between scopolamine (東莨菪鹼) and anisodamine (山莨菪鹼):
4. Clinical Applications of 654-2
1. Indications:
(1) Used to relieve smooth muscle spasms, gastrointestinal colic, biliary spasm:
Oral dosage: Adults, 5–10 mg each time, 3 times daily; children, 0.1–0.2 mg/kg each time, 3 times daily.
Injection dosage: Adults, 5–10 mg intramuscularly each time; children, 0.1–0.2 mg/kg, 1–2 times daily.
(2) Anti-shock and organophosphorus poisoning:
Intravenous injection, adults 10–40 mg each time, children 0.3–2 mg/kg each time. Repeat dosing every 10–30 minutes if necessary, dose can be increased.
After condition improves, gradually extend dosing intervals until discontinuation.
2. New clinical uses
(1) Reducing gastrointestinal reactions caused by azithromycin
The reason azithromycin causes gastrointestinal reactions is an increase in gastrointestinal motility, possibly due to acetylcholine release caused by stimulation of gastrin receptors in the gastrointestinal plexus.
654-2 is an M cholinergic receptor antagonist, competitively antagonizing the action of acetylcholine on M receptors, inhibiting smooth muscle movement, counteracting the gastrointestinal reactions caused by azithromycin.
(2) Treatment of infusion extravasation
External application of anisodamine injection combined with magnesium sulfate.
Anisodamine can relieve vasospasm and increase cells’ tolerance to ischemia and hypoxia, thus reducing the incidence of phlebitis and peripheral tissue necrosis. Combined with magnesium sulfate, it can further improve microcirculation, promote edema reabsorption, and relieve pain.
(3) Treatment of bronchial asthma
Anisodamine can relieve vasospasm and improve microcirculation. It can also block postganglionic vagal efferent branches, reduce vagal tension, dilate bronchi, relieve bronchospasm, reduce respiratory tract secretions, and improve respiratory function.
5. Adverse Reactions and Precautions
1. Adverse Reactions
Common reactions: dry mouth, facial flushing, blurred vision; less common: tachycardia, urinary retention; these symptoms usually disappear within 1–3 hours.
2. Precautions
Use cautiously in reflux esophagitis and severe ulcerative colitis. When acute abdomen diagnosis is not clear, avoid using it lightly; in summer, due to its sweat-inhibiting effect, body temperature may rise.
3. Contraindications
Contraindicated in increased intracranial pressure, acute cerebral hemorrhage, glaucoma, pyloric obstruction, intestinal obstruction, and prostatic hypertrophy.
4. Management of drug overdose
In overdose, atropine-like toxicity symptoms may occur. At this time, 1% physostigmine can be used for rescue, 0.25–0.5 ml per dose, subcutaneous injection every 15 minutes until symptoms alleviate.
Symptoms of atropine poisoning include: dilated pupils, facial flushing, dry skin, high fever, mental cloudiness, agitation, hallucinations, delirium, convulsions, tachycardia, and urinary retention. Severe cases may fall into coma and respiratory paralysis.