Oxybutynin Chemical structure
Mode of action and pharmacology
Oxybutynin is an antimuscarinic, antispasmodic medicine that is used to relieve urinary symptoms caused by an overactive bladder. An over active bladder is caused by involuntary contractions of the detrusor muscle surrounding the bladder causing it to empty unnecessarily. The detrusor muscle helps control normal working functions by relaxing and contracting as the bladder fills and empties. Symptoms include increased frequency and urgency to urinate, incontinence and bedwetting. (2)
Oxybutynin relieves symptoms by means of relaxing the smooth muscles within the bladder and stopping sudden muscle contractions. Oxybutynin also enables a larger volume of urine …show more content…
First-passage effect is high with less than 10% of the administered dose reaching circulation unchanged. Oxybutynin is widely distributed in body tissues following complete absorption. (5) “The volume of distribution was estimated to be 193 l after intravenous administration of 5 mg oxybutynin hydrochloride.” (5)
Oxybutynin is metabolized primarily by the cytochrome P450 enzyme systems found in the liver and small intestines through oxidation, reduction and hydrolysis. CYP3A4 converts Oxybutynin to its active metabolite, N-desethyloxybutynin. (9) Oxybutynin is extensively metabolized by the liver, with less than 0.1% of the administered dose excreted unchanged in the urine. Also, less than 0.1% of the administered dose is excreted as the metabolite. Half-life for immediate release Oxybutynin is 2-3 hours (7) however this will increase in elderly patients.
Oxybutynin comes in several forms to suit an individual’s needs and tolerance (immediate release tablet, modified release tablet, patches and oral liquid). (4) Patients should be counselled on cautions, side effects and how to take the dose in the form it is in. Doses, counselling and side effects vary depending upon which form of drug delivery is being
Mode of action and pharmacology
Oxybutynin is an antimuscarinic, antispasmodic medicine that is used to relieve urinary symptoms caused by an overactive bladder. An over active bladder is caused by involuntary contractions of the detrusor muscle surrounding the bladder causing it to empty unnecessarily. The detrusor muscle helps control normal working functions by relaxing and contracting as the bladder fills and empties. Symptoms include increased frequency and urgency to urinate, incontinence and bedwetting. (2)
Oxybutynin relieves symptoms by means of relaxing the smooth muscles within the bladder and stopping sudden muscle contractions. Oxybutynin also enables a larger volume of urine …show more content…
First-passage effect is high with less than 10% of the administered dose reaching circulation unchanged. Oxybutynin is widely distributed in body tissues following complete absorption. (5) “The volume of distribution was estimated to be 193 l after intravenous administration of 5 mg oxybutynin hydrochloride.” (5)
Oxybutynin is metabolized primarily by the cytochrome P450 enzyme systems found in the liver and small intestines through oxidation, reduction and hydrolysis. CYP3A4 converts Oxybutynin to its active metabolite, N-desethyloxybutynin. (9) Oxybutynin is extensively metabolized by the liver, with less than 0.1% of the administered dose excreted unchanged in the urine. Also, less than 0.1% of the administered dose is excreted as the metabolite. Half-life for immediate release Oxybutynin is 2-3 hours (7) however this will increase in elderly patients.
Oxybutynin comes in several forms to suit an individual’s needs and tolerance (immediate release tablet, modified release tablet, patches and oral liquid). (4) Patients should be counselled on cautions, side effects and how to take the dose in the form it is in. Doses, counselling and side effects vary depending upon which form of drug delivery is being