Title: Oxybutynin
CAS Registry Number: 5633-20-5
CAS Name: a-Cyclohexyl-a-hydroxybenzeneacetic acid 4-(diethylamino)-2-butynyl ester
Additional Names: a-phenylcyclohexaneglycolic acid 4-(diethylamino)-2-butynyl ester; 4-diethylamino-2-butynyl phenylcyclohexylglycolate; oxibutinina
Molecular Formula: C22H31NO3
Molecular Weight: 357.49
Percent Composition: C 73.91%, H 8.74%, N 3.92%, O 13.43%
Literature References: Muscarinic receptor antagonist. Prepn: GB 940540 (1963 to Mead Johnson). Physico-chemical properties: E. Miyamoto et al., Analyst 119, 1489 (1994). GC-MS determn in plasma: K. S. Patrick et al., J. Chromatogr. 487, 91 (1989). Toxicity: E. I. Goldenthal, Toxicol. Appl. Pharmacol. 18, 185 (1971). Review of pharmacodynamics and therapeutic use: Y. E. Yarker et al., Drugs Aging 6, 243-262 (1995).
Properties: pKa 8.04. Log P (n-octanol/water): 2.9 (pH 6). Soly in water (mg/ml): 77 (pH 1); 0.8 (pH 6); 0.012 (pH >9.6).
pKa: pKa 8.04
Log P: Log P (n-octanol/water): 2.9 (pH 6)
Derivative Type: Hydrochloride
CAS Registry Number: 1508-65-2
Additional Names: Oxybutynin chloride
Manufacturers' Codes: MJ-4309-1
Trademarks: Cystrin (Sanofi-Synthelabo); Ditropan (Sanofi-Synthelabo); Dridase (Sanofi-Synthelabo); Kentera (UCB); Pollakisu (Kodama); Tropax (BMS)
Molecular Formula: C22H31NO3.HCl
Molecular Weight: 393.95
Percent Composition: C 67.07%, H 8.19%, N 3.56%, O 12.18%, Cl 9.00%
Properties: Crystals, mp 129-130°. Sol in water, acids. Practically insol in alkali. LD50 orally in rats: 1220 mg/kg (Goldenthal).
Melting point: mp 129-130°
Toxicity data: LD50 orally in rats: 1220 mg/kg (Goldenthal)
Therap-Cat: In treatment of urinary incontinence.
Keywords: Antimuscarinic.
Oxychlorosene Oxycinchophen Oxyclozanide Oxycodone Oxyfedrine

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Systematic (IUPAC) name
4-Diethylaminobut-2-ynyl 2-cyclohexyl-2-hydroxy-2-phenylethanoate
Clinical data
Trade names Ditropan
AHFS/Drugs.com monograph
MedlinePlus a682141
Pregnancy cat. B
Legal status Rx Only (CA),[1] Rx Only oral and transdermal gel OTC transdermal patch(US)
Routes oral, transdermal gel, transdermal patch
Pharmacokinetic data
Protein binding 91%-93%
Half-life 12.4-13.2 hours
CAS number 5633-20-5 YesY
ATC code G04BD04
PubChem CID 4634
IUPHAR ligand 359
DrugBank DB01062
ChemSpider 4473 YesY
UNII K9P6MC7092 YesY
KEGG D00465 YesY
Chemical data
Formula C22H31NO3 
Mol. mass 357.486 g/mol
 YesY (what is this?)  (verify)

Oxybutynin (Ditropan, Lyrinel XL, Lenditro (South Africa)) is an anticholinergic medication used to relieve urinary and bladder difficulties, including frequent urination and inability to control urination (urge incontinence), by decreasing muscle spasms of the bladder.[2]

It competitively antagonizes the M1, M2, and M3 subtypes of the muscarinic acetylcholine receptor. It also has direct spasmolytic effects on bladder smooth muscle as a calcium antagonist and local anesthetic, but at concentrations far above those used clinically.

It is available orally in generic formulation or as the brand-names Ditropan, Lyrinel XL, or Ditrospam, as a transdermal patch under the brand name Oxytrol, and as a topical gel under the brand name Gelnique.

Oxybutynin is also a possible treatment of hyperhidrosis (hyper-active sweating).[3][4][5]

A 2009 Weill Cornell Medical College study concluded that patients switched to generic oxybutynin experienced a degradation in therapeutic value: "In women, there was a doubling of daytime frequency of urination, a slight 20% increase in nocturia, and a 46.3% increase in urge incontinence. In men, there was a 2.4-fold increase in daytime frequency, a 40% increase in nocturia, and a 40.6% increase in urge incontinence," Steven A. Kaplan said of the findings.[6]