Cyclopentolate

{{Short description|Pair of enantiomers}}

{{Drugbox

| Verifiedfields = changed

| Watchedfields = changed

| verifiedrevid = 460110763

| IUPAC_name = (RS)-2-(dimethylamino)ethyl (1-hydroxycyclopentyl)(phenyl)acetate

| image = Cyclopentolate.png

| image_class = skin-invert-image

| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}

| ChemSpiderID = 2802

| UNII_Ref = {{fdacite|correct|FDA}}

| UNII = I76F4SHP7J

| StdInChI_Ref = {{stdinchicite|correct|chemspider}}

| StdInChI = 1S/C17H25NO3/c1-18(2)12-13-21-16(19)15(14-8-4-3-5-9-14)17(20)10-6-7-11-17/h3-5,8-9,15,20H,6-7,10-13H2,1-2H3

| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}

| StdInChIKey = SKYSRIRYMSLOIN-UHFFFAOYSA-N

| CAS_number_Ref = {{cascite|correct|??}}

| CAS_number = 512-15-2

| ATC_prefix = S01

| ChEMBL_Ref = {{ebicite|changed|EBI}}

| ChEMBL = 1200473

| ATC_suffix = FA04

| ATC_supplemental =

| DrugBank_Ref = {{drugbankcite|correct|drugbank}}

| DrugBank = DB00979

| ChEBI_Ref = {{ebicite|correct|EBI}}

| ChEBI = 4024

| PubChem = 2905

| KEGG_Ref = {{keggcite|correct|kegg}}

| KEGG = D07759

| smiles = O=C(OCCN(C)C)C(c1ccccc1)C2(O)CCCC2

| C=17 | H=25 | N=1 | O=3

| bioavailability =

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| pregnancy_category = C

| legal_AU =

| legal_BR = C1

| legal_BR_comment = {{Cite web |author=Anvisa |author-link=Brazilian Health Regulatory Agency |date=2023-03-31 |title=RDC Nº 784 - Listas de Substâncias Entorpecentes, Psicotrópicas, Precursoras e Outras sob Controle Especial |trans-title=Collegiate Board Resolution No. 784 - Lists of Narcotic, Psychotropic, Precursor, and Other Substances under Special Control|url=https://www.in.gov.br/en/web/dou/-/resolucao-rdc-n-784-de-31-de-marco-de-2023-474904992 |url-status=live |archive-url=https://web.archive.org/web/20230803143925/https://www.in.gov.br/en/web/dou/-/resolucao-rdc-n-784-de-31-de-marco-de-2023-474904992 |archive-date=2023-08-03 |access-date=2023-08-16 |publisher=Diário Oficial da União |language=pt-BR |publication-date=2023-04-04}}

| legal_CA =

| legal_DE =

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| routes_of_administration = Topic

}}

Cyclopentolate is a muscarinic antagonist.{{cite web|url=http://www.drugbank.ca/drugs/DB00979|title=Cyclopentolate | work = Drug Bank |access-date=June 15, 2012}} It is commonly used as an eye drop during pediatric eye examinations to dilate the eye (mydriatic) and prevent the eye from focusing/accommodating (cycloplegic). Cyclopentolate{{cn|date=January 2024}} or atropine can also be administered to reverse muscarinic and central nervous system effects of indirect cholinomimetic (anti-AChase) administration.

It is on the World Health Organization's List of Essential Medicines.{{cite book | vauthors = ((World Health Organization)) | title = World Health Organization model list of essential medicines: 22nd list (2021) | year = 2021 | hdl = 10665/345533 | author-link = World Health Organization | publisher = World Health Organization | location = Geneva | id = WHO/MHP/HPS/EML/2021.02 | hdl-access=free }}

After instillation of cyclopentolate, pupil dilation (mydriasis) typically lasts up to 24 hours, while paralysis of the ciliary muscle (cycloplegia) typically lasts 6-24 hours.{{cite book | chapter = Chapter 9: Cycloplegics. Table 9-1: Mydriatic and Cycloplegic Properties of Anticholinergic Agents | pages = 127 | veditors = Bartlett JD, Jaanus SD |title=Clinical Ocular Pharmacology |date=2008 |publisher=Butterworth Heinemann - Elsevier |location=Saint Louis |isbn=978-0-7506-7576-5 |edition=5th}} During this time, patients may be more light sensitive than normal and may notice close objects blurred (and possibly distant objects blurred, depending on the patient's visual system). Cyclopentolate is often chosen as a milder, shorter-lasting, cycloplegic alternative to atropine, another cycloplegic agent which lasts much longer. Tropicamide is an even shorter-lasting cycloplegic than cyclopentolate, but is less reliable for finding latent hyperopia. Cyclopentolate drops act rapidly to dilate the pupil.{{Cite web|url=http://www.medsafe.govt.nz/profs/Datasheet/c/Cyclogyleyedrop.pdf|title=Cyclogyl Eye Drops Medsafe data sheet New Zealand|date=11 January 2017|access-date=3 June 2017}}

The side and adverse effects of cyclopentolate are similar to the side and adverse effects of other anticholinergic medications. Because of that, extra caution should be taken when prescribing cyclopentolate to patients who are already taking other anticholinergic drugs. A possible ocular (eye-related) side effect is increase in pressure inside the eye, which is of particular concern when there is a predisposition toward or a presence of glaucoma. Other ocular side effects can include burning sensations, discomfort with bright light (photophobia), blurred vision, irritation, inflammation of the eye mucous membranes (conjunctivitis), inflammation of the cornea of the eye (keratitis), and other issues. Nonocular (not eye-related) side and adverse effects can include neuropsychiatric symptoms.{{cite journal | vauthors = Derinoz O, Er A | title = Inability to walk, disequilibrium, incoherent speech, disorientation following the instillation of 1% cyclopentolate eyedrops: case report | journal = Pediatric Emergency Care | volume = 28 | issue = 1 | pages = 59–60 | date = January 2012 | pmid = 22217890 | doi = 10.1097/PEC.0b013e3182417a63 }} like subtle concentration and memory problems, subtle decision-making problems, drowsiness, and more pronounced disorientation to time and place, confusion, disturbances of speech and movement, hyperactivity, restlessness, and seizures. Temporary psychosis{{cite journal | vauthors = Rajappa N, Patra S, Bhalsing S, Lune AA | title = A case of acute psychosis induced by topical cyclopentolate eye drops in an elderly patient. | journal = Medical Journal of Dr. D.Y. Patil University | date = January 2014 | volume = 7 | issue = 1 | pages = 68–69 | doi = 10.4103/0975-2870.122789 | doi-access = free }} can develop that includes hallucinations, particularly when higher doses are used in children or older adults{{cite journal | vauthors = Barker DB, Solomon DA | title = The potential for mental status changes associated with systemic absorption of anticholinergic ophthalmic medications: concerns in the elderly | journal = DICP: The Annals of Pharmacotherapy| volume = 24 | issue = 9 | pages = 847–850 | date = September 1990 | pmid = 2260344 | doi = 10.1177/106002809002400911 | s2cid = 6896684 }} on other anticholinergic medications.{{cite journal | vauthors = Carpenter WT | title = Precipitous mental deterioration following cycloplegia with 0.2 percent cyclopentolate HCl | journal = Archives of Ophthalmology | volume = 78 | issue = 4 | pages = 445–447 | date = October 1967 | pmid = 6046837 | doi = 10.1001/archopht.1967.00980030447006 }} Patients with dementia of the Alzheimer's type can experience worsening of their dementia symptoms. Additional side and adverse effects can include skin flushing, skin rashes, gastrointestinal problems, increased heart beat (tachycardia), increased body temperature (hyperpyrexia), blood vessel dilation, urinary retention, dry mouth and reduced sweating, and reduced bronchial secretions. Severe poisoning with cyclopentolate may result in coma, paralysis of breathing, and death. Cyclopentolate derivatives can be used as an antidote for organophosphate poisoning.{{cite journal | vauthors = Bryant SM, Rhee JW, Thompson TM, Lu JJ, Aks SE | title = Parenteral ophthalmic tropicamide or cyclopentolate protects rats from lethal organophosphate poisoning | journal = American Journal of Therapeutics | volume = 16 | issue = 3 | pages = 231–234 | date = 2009 | pmid = 19454862 | doi = 10.1097/MJT.0b013e318182254b | s2cid = 36599696 }}{{cite journal | vauthors = Bauer CR, Trottier MC, Stern L | title = Systemic cyclopentolate (Cyclogyl) toxicity in the newborn infant | journal = The Journal of Pediatrics | volume = 82 | issue = 3 | pages = 501–505 | date = March 1973 | pmid = 4698940 | doi = 10.1016/s0022-3476(73)80134-9 }}

{{cite journal | vauthors = Fitzgerald DA, Hanson RM, West C, Martin F, Brown J, Kilham HA | title = Seizures associated with 1% cyclopentolate eyedrops | journal = Journal of Paediatrics and Child Health | volume = 26 | issue = 2 | pages = 106–107 | date = April 1990 | pmid = 2113819 | doi = 10.1111/j.1440-1754.1990.tb02399.x | s2cid = 20030473 }}{{cite journal | vauthors = Bhatia SS, Vidyashankar C, Sharma RK, Dubey AK | title = Systemic toxicity with cyclopentolate eye drops | journal = Indian Pediatrics | volume = 37 | issue = 3 | pages = 329–331 | date = March 2000 | pmid = 10750080 | doi = }}{{cite journal | vauthors = Ozgun U, Demet T, Ozge KA, Zafer D, Murat S, Mehmet Y, Nilgun K | title = Fatal necrotising enterocolitis due to mydriatic eye drops | journal = Journal of the College of Physicians and Surgeons--Pakistan | volume = 24 | issue = Suppl 2 | pages = S147–S149 | date = May 2014 | pmid = 24906272 | doi = }}

Lethality of cyclopentolate has been studied in rodents. The LD50 (the dose at which 50% of animals die from the drug) is approximately 4000 mg/kg in rats and 960 mg/kg in mice. Readily recognizable symptoms of overdose include tachycardia, dizziness, dry mouth, behavioral disturbances, uncoordination, and drowsiness.

Cycloplegia is necessary in cases of suspected latent hyperopia (or "over-focusing") so that an ophthalmologist or optometrist can accurately measure how much a person has to flex their focusing muscle (accommodation) in order to see in the distance and up-close. Correction of latent hyperopia in children can often prevent, or sometimes correct, unwanted eye turns (strabismus), some forms of refractive amblyopia, and may alleviate eye strain or frontal headaches caused by prolonged near-work. Cycloplegia is also helpful in relieving accommodative spasm.