[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Pharmacology](https://durgical.com/en/pharmacology/) › [Overactive bladder agents](https://durgical.com/en/pharmacology/classes/overactive-bladder-agents/) › Oxybutynin

[Pharmacology](https://durgical.com/en/pharmacology/) · [Overactive bladder agents](https://durgical.com/en/pharmacology/classes/overactive-bladder-agents/)

# Oxybutynin

The oldest antimuscarinic for the overactive and neurogenic bladder. It works well but often causes dry mouth, constipation and, in older adults, confusion.

Updated 2026-11-01

- Class: [Overactive bladder agents](https://durgical.com/en/pharmacology/classes/overactive-bladder-agents/)
- Receptor: Muscarinic M3 receptor of the bladder detrusor
- ATC code: G04BD04

◎**Muscarinic M3 receptor of the bladder detrusor**Oxybutynin

ⓘ No structure of oxybutynin bound to its receptor exists. The figure shows tiotropium, another muscarinic antagonist, in the acetylcholine pocket of the rat M3 receptor, the subtype that contracts the bladder; the pocket is nearly identical in the human receptor.

**Target in 3D:** Muscarinic M3 receptor of the bladder detrusor. PDB structure 4DAJ (RCSB PDB, public domain). [View the structure at RCSB PDB](https://www.rcsb.org/structure/4DAJ) · Drag to rotate · pinch to zoom

## Mechanism of action

Oxybutynin blocks the muscarinic action of acetylcholine on bladder smooth muscle and also has a direct antispasmodic effect on it. Fewer uninhibited detrusor contractions mean less urgency, frequency and leakage. It does not block skeletal neuromuscular junctions or autonomic ganglia. A metabolite, desethyloxybutynin, is also active.

- Blocks muscarinic receptors of the detrusor
- Also relaxes bladder smooth muscle directly
- Uninhibited contractions decrease
- Urgency, frequency and leakage ease

## Pharmacokinetics

**Absorption**
Absorbed rapidly by mouth, but bioavailability is only about 6% because of first-pass metabolism; skin patch and gel forms avoid much of it

**Metabolism**
By CYP3A4 in the gut wall and liver, to the active desethyloxybutynin

**Half-life**
About 2 to 3 hours (immediate-release), longer in frail older adults

## Indications

- Bladder instability in uninhibited or reflex neurogenic bladder (urgency, frequency, urge incontinence), including children from age five [Neurogenic bladder →](https://durgical.com/en/conditions/neurogenic-bladder/)
- Overactive bladder [Overactive bladder and urge incontinence →](https://durgical.com/en/conditions/overactive-bladder-and-urge-incontinence/)

## Adverse effects

### Common

- Dry mouth, very common
- Constipation
- Blurred vision
- Drowsiness and dizziness
- Less sweating

### Serious (rare, important)

- Confusion, agitation and hallucinations, mainly in older adults
- Angioedema of face, tongue or larynx, sometimes after the first dose
- Heat stroke from reduced sweating
- Urinary retention

## Contraindications

- Urinary retention
- Gastric retention and other severe slowing of gut movement
- Uncontrolled narrow-angle glaucoma
- Hypersensitivity to oxybutynin

## Key interactions

**Strong CYP3A4 inhibitors (ketoconazole, clarithromycin, ritonavir, grapefruit juice)**
Higher oxybutynin levels; ketoconazole raised them about three to four times

**Other anticholinergic drugs**
More dry mouth, constipation and drowsiness

**Cholinesterase inhibitors for dementia (donepezil, rivastigmine)**
Opposite actions; each weakens the other

## What is monitored

- Confusion or memory change, especially in the first months
- Post-void residual volume if retention is suspected
- Bowel habit

## Administration and safety

- Tablets by mouth; extended-release forms are swallowed whole
- A lower starting dose is used in frail older adults, in whom the half-life is longer

## Nursing care

- Teach sips of water or sugar-free gum for dry mouth
- Encourage fibre and fluids for constipation
- Warn about heat and exercise in hot weather
- Ask families to report new confusion in older adults

## Pregnancy and breastfeeding

Safety in pregnancy is not established; it is given only when the benefit outweighs the risk.

## Memory aid

OXYbutynin = «OX-dry»: dries the mouth like an ox's hide; skin forms are kinder.

## Test yourself

Think of the answer, then tap the question to see it.

## Why is oral oxybutynin's bioavailability low?

Extensive first-pass metabolism by CYP3A4 in the gut wall and liver.

## Which patient group is most at risk of confusion with oxybutynin?

Older adults, especially those with cognitive impairment.

## What is the most common side effect of oxybutynin?

Dry mouth.

[Add to my cards (3)](https://durgical.app/estudiar/?add=/en/pharmacology/oxybutynin/)

## Related drugs

- [Tolterodine](https://durgical.com/en/pharmacology/tolterodine/)
- [Solifenacin](https://durgical.com/en/pharmacology/solifenacin/)
- [Mirabegron](https://durgical.com/en/pharmacology/mirabegron/)

## Related conditions

- [Neurogenic bladder](https://durgical.com/en/conditions/neurogenic-bladder/)
- [Overactive bladder and urge incontinence](https://durgical.com/en/conditions/overactive-bladder-and-urge-incontinence/)

[← Back to the class: Overactive bladder agents](https://durgical.com/en/pharmacology/classes/overactive-bladder-agents/)

Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.

Sources: [DailyMed - OXYBUTYNIN CHLORIDE tablet](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=9578b6b8-5b9d-4263-9142-39b2c7216b85) (DailyMed (U.S. National Library of Medicine), 2026); [Oxybutynin: MedlinePlus Drug Information](https://medlineplus.gov/druginfo/meds/a682141.html) (MedlinePlus (U.S. National Library of Medicine), 2026); Goodman & Gilman's The Pharmacological Basis of Therapeutics, 14th ed., ch. 11 (McGraw Hill, 2023); [ATCDDD - ATC/DDD Index](https://atcddd.fhi.no/atc_ddd_index/?code=G04BD04) (WHO Collaborating Centre for Drug Statistics Methodology, 2026).

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Representative model, for educational purposes only.

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Source: https://durgical.com/en/pharmacology/oxybutynin/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/pharmacology/oxybutynin/