How atropine works
Atropine is an active substance from the group of parasympatholytics (also called anticholinergics or muscarinic receptor antagonists). Its parasympatholytic (inhibiting the parasympathetic nervous system) properties ensure, among other things, that smooth muscle in the gastrointestinal tract, bile ducts, and urinary tract slackens.
In addition, atropine inhibits the secretion of saliva, lacrimal fluid and sweat. It also reduces mucus production in the lungs and dilates the pupils of the eye. In higher doses, atropine increases the heartbeat (positive chronotropic effect).
Sympathetic and parasympathetic nervous system
The autonomic (involuntary) nervous system consists of two parts that act like opposites to each other: the sympathetic and parasympathetic nervous systems.
However, when the sympathetic nervous system (sympathetic nervous system) is activated, the body is set up to perform – the heartbeat speeds up, the pupils dilate, and the digestive output shuts down. This stress response is also known as the “fight-or-flight” response (“fight or flight”).
The active ingredient atropine inhibits the parasympathetic nervous system in the body, which can result in indirect sympathetic effects depending on the dose. As mentioned above, these include, for example, dilated pupils, inhibition of intestinal activity and saliva production.
Poisoning with poisons that strongly stimulate the action of the parasympathetic nervous system can also be treated with atropine as an antidote. Such poisons include the chemical warfare agents sarin, soman, and tabun (G warfare agents) and the insecticide E 605 (parathion).
Uptake, degradation and excretion
This free atropine is rapidly broken down (in two to three hours) and excreted by the kidneys. The smaller, bound portion is excreted more slowly over a period of about twelve to 38 hours.
When is atropine used?
Atropine is used for a variety of indications (uses). These include:
- Spasms in the stomach and intestines, biliary and urinary tracts
- @ Inhibition of secretion by the gastric glands and pancreas
Atropine is administered into the vein (intravenously) for:
- Preparation for anesthesia (anesthetic premedication).
- Treatment of bradycardic cardiac arrhythmias (arrhythmia accompanied by a slowed heartbeat)
- @ Treatment of poisoning with G-warfare agents and insecticides
Eye drops containing atropine are used for pupil dilation in the following cases:
- before examinations of the fundus of the eye
- @ in cases of ocular inflammation (e.g. iris dermatitis)
Outside the approved indications (off-label use), atropine drops are also used, among other things, to reduce saliva production, for example in cases of abnormal salivation (hypersalivation) or the intake of certain medications (e.g., clozapine).
How atropine is used
The active ingredient is used locally whenever possible, such as in the form of atropine eye drops and drops for use in the mouth. Injection solutions, tablets, or suppositories are used to treat internal organs or poisoning.
Dosage and frequency of use are individually adjusted to the patient by the attending physician.
After using eye drops containing atropine, you should not drive vehicles or operate machinery, as the active substance impairs visual performance and reaction.
What are the side effects of atropine?
Atropine side effects are strongly dose-dependent.
Especially in higher doses, atropine may also cause hallucinations, speech disorders, convulsions, increase in blood pressure, muscle weakness, urinary retention, states of confusion, agitation and agitation.
What should be considered when taking atropine?
Contraindications
Atropine should not be used in:
- narrow-angle glaucoma (a form of glaucoma)
- pathological narrowing of the coronary vessels (coronary stenosis)
- Cardiac arrhythmias with accelerated heartbeat (tachycardic arrhythmias)
- Bladder emptying disorder with residual urine formation
- benign prostate enlargement
- Myasthenia gravis (autoimmune disease of nerves and muscles)
Drug interactions
In combination with agents that also have an inhibitory effect on the parasympathetic nervous system, the effect of atropine may be increased. This favors side effects.
Age restriction
Atropine tablets can be given in appropriate doses to infants as young as two years of age. Atropine eye drops are approved for infants as young as three months. Intravenous atropine medications are used for acute life-threatening conditions (e.g., severe poisoning) beginning at birth.
Pregnancy and lactation
Atropine crosses the placenta and can thus enter the body of the unborn child. It should therefore be used in pregnancy only after a strict risk-benefit assessment, even though data to date show no evidence of an increased risk of malformation.
Atropine passes into breast milk in small amounts. To date, there are no reports of adverse effects in the breastfed infant. Therefore, short-term use during breastfeeding appears to be acceptable – with careful observation of the child.
Monitor your child closely when using preparations containing atropine during breastfeeding.
In most cases, atropine is used directly by the doctor. For all other purposes, the corresponding preparations are available on prescription in pharmacies in Germany, Austria and Switzerland.
Only homeopathic preparations are exempt from the prescription requirement.
How long has atropine been known?
As early as the fourth century BC, Theophrastus of Eresos described the effectiveness of mandrake, a plant containing atropine, for the treatment of wounds, gout and insomnia. The use of atropine-containing plants has been documented repeatedly over the centuries. Particularly well known is the use to dilate pupils for cosmetic purposes, for example by Cleopatra.
In 1831, the German pharmacist Heinrich Mein was able to isolate atropine for the first time. In 1901, the active ingredient was produced artificially for the first time by Richard Willstätter.
