Oxybutynin HCl is a medication used to treat symptoms of overactive bladder such as urinary frequency, urgency, and incontinence. It works by relaxing the muscles in the bladder to decrease the frequency and urgency of urination. It is available in various forms, including tablets, extended-release tablets, syrup, and transdermal patches. It is usually taken orally, with or without food, as directed by a healthcare provider. Some common side effects of oxybutynin HCl include dry mouth, constipation, blurred vision, dizziness, and drowsiness.