Oxybutynin
Mechanism :
Oxybutynin chloride exerts a direct antispasmodic effect on smooth muscle and inhibits the muscarinic action of acetylcholine on smooth muscle.
Indication :
- Urinary urgency, frequency
- Urinary incontinence
- Nocturnal enuresis
- Neurogenic bladder instability/detrusor overactivity
Contraindications :
Contraindicated in patients with urinary retention, gastric retention, or uncontrolled narrow-angle glaucoma and in patients who are at risk for these conditions, in patients who have demonstrated hypersensitivity to the drug substance or other components of the product.
Dosing :
Oral:
>5 years:
0.2 mg/kg PO in 2-3 divided doses. Max: 15 mg/day.
Transdermal patch:
It is available as 3.9 mg patch. Can use in children >4 years for overactive bladder as 1 patch twice a week.
Adverse Effect :
Dry mouth, constipation, somnolence, nausea, blurred vision, pauses, abdominal discomfort, facial flushing, headache, dizziness, diarrhea.
Interaction :
Anticholinergic Drugs: The concomitant use of oxybutynin with other anticholinergic drugs or with other agents which produce dry mouth, constipation, somnolence (drowsiness), and/or other anticholinergic-like effects may increase the frequency and/or severity of such effects.
Renal Dose :
Dose in Renal Impairment GFR (mL/min)
| 20-50 | Dose as in normal renal function |
| 10-20 | Dose as in normal renal function |
| <10 | Dose as in normal renal function |
Dose in Patients undergoing Renal Replacement Therapies
| CAPD | Dialysed. Dose as in normal renal function |
| HD | Dialysed. Dose as in normal renal function |
| HDF/High flux | Dialysed. Dose as in normal renal function |
| CAV/VVHD | Dialysed. Dose as in normal renal function |
Hepatic Dose :
Usage with caution is recommended, dose may need to be reduced, however guidelines do not specify dose, as it has not been studied. Dose should not exceed 5 mg/dose and daily 20mg. Extended release preparations should be avoided.