Atropine mydriasis

Anticholinergic mydriasis, also known as pharmacologic blockade or atropinic mydriasis, refers to a fixed and dilated pupil resulting from the instillation or inoculation into the eye of drugs or substances with anticholinergic properties. Medical personnel such as doctors, nurses,... 

The alkaloid is principally used in medicine to cause dilatation of the pupil of the eye (mydriasis), due to paralysis of the circular muscle of the ns. The accommodation is also paralysed as a result of action on the ciliary muscle (cycloplegia). Atropine is also used in conditions where... 

Central nervous sysfe/n-dreamless sleep, drowsiness atropine may produce mild stimulation in some patients e-mydriasis (dilatation of the pupil), cydoplegia (paralysis of accommodation or inability to focus the eye)... 

Monitor for adverse effects of medications, such as atropine (dry mouth, mydriasis, urinary retention, and tachycardia). 

Inspection of the retina during an ophthalmoscopic examination is greatly facilitated by mydriasis, or the dilation of the pupil. Parasympathetic stimulation of the circular muscle layer in the iris causes contraction and a decrease in the diameter of the pupil. Administration of a muscarinic receptor antagonist such as atropine or scopolamine prevents this smooth muscle contraction. As a result, sympathetic stimulation of the radial muscle layer is unopposed, causing an increase in the diameter of the pupil. These agents are given in the form of eye drops that act locally and limit the possibility of systemic side effects. 

Parasympatholytics are used to induce a mydriasis in the ophthalmology for the examination of the retina. They are applied locally as drops or ointment. The drug-induced inability of the eyes to accommodate results in a serious, although transient, impairment of the visus. Therefore the long-acting atropine (7-10 days) is replaced by short-acting compounds like homatropine (1-3 days), cyclopentolate (1 day) or tropicamide (6 hours). 

Antimuscarinic drugs block contraction of the iris sphincter and ciliary muscles of the eye produced by ACh. This results in dilation of the pupil (mydriasis) and paralysis of accommodation (cycloplegia), responses that cause photophobia and inability to focus on nearby objects. Ocular effects are produced only after higher parenteral doses. Atropine and scopolamine produce responses lasting several days when applied directly to the eyes. 

Effect on eye Atropine produces mydriasis by blocking the cholinergic nerves supplying the smooth muscles of sphincter of the iris on local administration into the eye. It also produces paralysis of accommodation or cycloplegia (the condition in which, one can see things... 

As mydriatic and cycloplegic agent Atropine is used to produce mydriasis and cycloplegia for testing errors of refraction. Mydriasis is required for fundoscopic examination and in the treatment of iritis and keratitis. 

More potent than atropine. Used in eye and onset of mydriasis and cycloplegia is similar to that of atropine but homatropine is not much used for producing cycloplegia. 

The pupillary constrictor muscle (see Figure 6-9) depends on muscarinic cholinoceptor activation. This activation is blocked by topical atropine and other tertiary antimuscarinic drugs and results in unopposed sympathetic dilator activity and mydriasis (Figure 8-3). Dilated pupils were considered cosmetically desirable during the Renaissance and account for the name belladonna (Italian, "beautiful lady") applied to the plant and its active extract because of the use of the extract as eye drops during that time. 

Redrawn from Marron J Cycloplegia and mydriasis by use of atropine, scopolamine, and homatropine-paredrine. Arch Ophthalmol 1940 23 340.)... 

Eye. Atropine and similar antimuscarinics block the acetylcholine-mediated contraction of the pupillary sphincter muscle, thus causing dilation of the pupil (mydriasis).1 During an ophthalmologic exam, these drugs may be applied topically in order to dilate the pupil, thus allowing a more detailed inspection of internal eye structures such as the retina. 

Atropine toxicity is characterized by dry mouth, burning sensation in the mouth, rapid pulse, mydriasis, blurred vision, photophobia, dry and flushed skin, restlessness, and excitement. 

At higher concentrations, atropine causes block of all parasympathetic functions. However, atropine is a remarkably safe drug in adults. Atropine poisoning has occurred as a result of attempted suicide, but most cases are due to attempts to induce hallucinations. Poisoned individuals manifest dry mouth, mydriasis, tachycardia, hot and flushed skin, agitation, and delirium for as long as a week. Body temperature is frequently elevated. These effects are memorialized in the adage, "dry as a bone, blind as a bat, red as a beet, mad as a hatter."... 

Intoxications with higher concentrations will cause tachycardia, mydriasis, CNS excitations and hallucinations, coma and ultimately death [42], Incorporation of atropine (more correctly S-hyoscyamine) is the predominant reason for TA intoxication after ingestion of Datura plants. 

Incidental and accidental intake of atropine and scopolamine, which are the main tropane alkaloids in plants of the solanecae family, may provoke poisoning of man and livestock [11,13-15, 55, 57,119-122] causing agitation, aggression, hallucinations, dry mouth and skin, mydriasis, loss of consciousness followed by coma combined with tachycardia, hypotension, and hyperthermia [57, 121], A detailed statistical analysis of paediatric plant exposures in Germany within the years 1998-2004 has been provided by Pietsch et al. [123], They found that most prevalent victims of accidental plant exposures are children in the age of 1-6 years presumably being misled by the attractive plump berries. 

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