OTC Oxytrol now available in retail pharmacies

In January 2013 the Food and Drug Administration approved a change in status for Oxytrol from prescription to over-the-counter (OTC) under the product name Oxytrol for Women. Recently, Oxytrol for Women has become available for purchase in retail pharmacies. The active ingredient in these patches is oxybutynin, delivered at a dose of 3.9 mg per day. The approved indication for the OTC use of this patch is for the treatment of overactive bladder in women 18 years of age or older.

Overactive bladder can be defined as urinary urgency with or without urge incontinence, usually accompanied by frequency and nocturia, in the absence of a urinary tract infection or other obvious pathology. It is estimated that overactive bladder affects approximately 16% of men and women over the age of 40. There are multiple causes or contributing factors to overactive bladder, some of which include infection, estrogen deficiency, neurologic conditions like stroke or multiple sclerosis, diabetes, heart failure, dietary factors such as excess caffeine, and adverse effects of medication.

Efficacy

The impact of Oxytrol 3.9 mg/day on patient outcomes has been evaluated in randomized controlled trials in patients with overactive bladder and urge incontinence or mixed incontinence.

The first trial enrolled patients with at least 10 episodes of urge or primarily urge incontinence episodes daily. Participants were primarily white females with a mean age of 61.4 years. Patients applied either one patch twice weekly to deliver 3.9 mg of oxybutynin daily or placebo patches. The change in incontinent episodes from baseline to 12 weeks was significantly greater in the oxybutynin group compared to placebo (-19 vs. -14.5, P=0.0165). There was also a significant decrease in average daily urinary frequency in the oxybutynin group compared to placebo (-2.3±2.5 vs. -1.7±3.0, P=0.0457), while the average volume of voided urine increased significantly in treated patients. It is important to note, though, that patients in the trial were instructed to follow nonpharmacologic interventions, including timed urination, pelvic floor exercises, and fluid management.

The second trial evaluated a similar population of predominately white females in their early 60s having four or more urge or primarily urge incontinent episodes in a three-day period. This trial asked patients to maintain usual fluid intake and participation in any nonpharmacologic interventions already underway for overactive bladder control. The change from baseline to week 12 in median number of daily incontinent episodes was significantly greater in the oxybutynin group compared to placebo (-3 vs. -2, P=0.0137).⁶ In this trial, tolterodine LA 4 mg daily was also used as a comparator and similar results were observed compared to placebo. No significant difference was found in a comparison of oxybutynin to tolteridone LA. Both treatments decreased daily urinary frequency vs. placebo.

Safety

The use of Oxytrol, an antimuscarinic agent, is associated with several adverse effects; however, fewer adverse effects are associated with longer-acting preparations such as the patch than with short-acting products. The most common adverse reaction to the transdermal patch is pruritus, which was reported in up to 16.8% of patients in the placebo controlled trial above, compared to 6% in placebo patients. Additional common side effects in the trial of oxybutynin compared to placebo include dry mouth (9.6% vs. 8.3%), dizziness (4.0% vs. 3.8%) and dysuria (2.4% vs. 0%). In the trial comparing the oxybutynin patch to tolteridone LA, more adverse events occurred in the tolteridone group (29 versus 23); incidents of common side effects of dry mouth and constipation were comparable.  

The OTC labeling specifically recommends that patients with the following characteristics refrain from OTC use of Oxytrol for Women: presence of pain or burning upon urination, blood in the urine, unexplained lower back or side pain, cloudy or foul-smelling urine, diagnosis of urinary or gastric retention, glaucoma, or hypersensitity to oxybutynin. Individuals who should not use this product include those under the age of 18; patients in which the only accidental urine loss experienced is upon sneezing, laughing, or coughing; and men.

Dosing

The dose for Oxytrol for Women is one patch worn for four consecutive days, after which the patch should be removed and a new patch applied. The patch should be applied to a clean, dry, smooth area of the skin located on the abdomen, buttocks, or hips. Patients should refrain from placing the patch on oily, irritated, or damaged skin, or skin to which oil, lotion, or powder has been applied. The patch should be worn under clothes and not exposed to sunlight or cut into smaller pieces. With each new application, patients should rotate the spot where the patch is applied. If the patch falls off and the patient cannot stick it back in place, a new patch should be applied to a new location. 

Diana M. Sobieraj is assistant professor of Pharmacy Practice, University of Connecticut School of Pharmacy, Storrs, Conn.