Role of the anticholinergenics in Parkinson’s disease, The

Atropine is a tropane alkaloid extracted from plants of the family Solanaceae. The term "tropane" is derived from just one genus in the family Solanaceae -  Atropa (the belladonna genus),  named after the Greek Fate, Atropos, who cut the thread of life. The name should give you some idea of the potential toxicity and lethality of these compounds.  Tropane alkaloids include three  important ones from our perspective -  atropine, scopolamine, and hyoscyamine.

Pharmacologically, they are the most powerful known anticholinergics in existence.

The pharmaceutical industry use atropine in a number of drugs.  Belladonna is the main source.  It is used to treat iritis – inflammation of the iris and corneal ulcer, as well as to dilute the pupil in order to examine the eye.  Atropine is also used as a premedication before general anaesthesia to reduce secretions from the lungs and is used as an emergency treatment for bradycardia – abnormally low heartbeat.  It is also occasionally prescribed for its antispasmodic effects and used in combination with other drugs to help those with diarrhoea.  And it is used in anti-Parkinsonian medications to control the tremors. 

At too high a dose it results in intense hallucinations, and a number of  other side effects. One or more of the following has been experienced, though it depends on dose, plus what you have eaten.

• Overheat [because you have stopped the perspiration system] – in this case people can go bright red in the face or even purple!  Temperatures have been known over 100 degrees fahrenheit!

• Suffer enormous thirst and a dry mouth [because you have stopped the salivation system]

• Have heart arrhythmias and even heart failure – [because you have disrupted the heart system] for example in healthy males being anaesthetised ready for dental surgery, one source found that a dose of only 0.4mg atropine intravenously 5 minutes before induction caused a drop in blood pressure, ‘stroke volume and total peripheral resistance’.  The heart has been seen to go faster and slower

• Twitch, pick, pluck, grasp, gather or act with no control because their system of muscle control has been inhibited [hyperreflexia]

• Suffer dreadful constipation – because you have stopped their poo system

• Suffer dreadful urine retention – because you have stopped their wee system

• Suffer loss of the ability to blink or have any pupillary response, you can get intense and painful drying of the eyes and mucous membranes, as well as a pronounced dilation of the pupils which can last for several days resulting in sensitivity to light, blurry vision and inability to read.  In very severe cases people have been known to get glaucoma.

• Suffer loss of your systems of balance – and as a consequence suffer from giddiness and a sort of ‘motion sickness’

To others, if you are still able to walk and talk, you will appear incoherent, confused and disoriented, and have slurred speech.

And you could die if the dose is really wrong.